期刊文献+
共找到3,080篇文章
< 1 2 154 >
每页显示 20 50 100
提高中国稻田氮肥利用率的研究策略 被引量:1050
1
作者 彭少兵 黄见良 +7 位作者 钟旭华 杨建昌 王光火 邹应斌 张福锁 朱庆森 Roland Buresh christian Witt 《中国农业科学》 CAS CSCD 北大核心 2002年第9期1095-1103,共9页
介绍了中国水稻生产氮肥使用及利用率概况。中国氮肥消费量占世界氮肥总量的 30 %,水稻生产所消耗的氮肥占世界水稻氮肥总消耗量的 37%。与主要产稻国相比 ,中国水稻生产氮肥施用量较高而利用率较低 ;介绍了国际上公认的氮肥利用率的概... 介绍了中国水稻生产氮肥使用及利用率概况。中国氮肥消费量占世界氮肥总量的 30 %,水稻生产所消耗的氮肥占世界水稻氮肥总消耗量的 37%。与主要产稻国相比 ,中国水稻生产氮肥施用量较高而利用率较低 ;介绍了国际上公认的氮肥利用率的概念和相应的定量方法 ;总结了国内外水稻氮肥的施用方法 ,肥料种类 ,计算机推荐施肥以及实时施氮管理模式等对降低氮素损失 ,提高氮肥利用率的研究概况和研究进展 ;从水稻品种耐肥性、土壤供肥能力、施肥技术及水分管理等多方面分析了中国水稻氮肥利用率低的可能原因 ;提出了通过改善水稻品种对氮肥的敏感反应 ,以作物氮素状况为指导适时和适量施用氮肥 ,以及合理调节土壤背景氮来降低氮素损失 ,提高水稻的氮肥利用率的研究策略。 展开更多
关键词 水稻 氮肥 施肥管理 肥料利用率
下载PDF
蔬菜中铅镉铜锌含量的影响因素研究 被引量:96
2
作者 祖艳群 李元 +3 位作者 陈海燕 陈建军 Marianne Guhur christian Schvartz 《农业环境科学学报》 CAS CSCD 北大核心 2003年第3期289-292,共4页
用通过大田调查的方法,研究了影响蔬菜中Pb、Cd、Cu、Zn含量的因素。结果表明:(1)蔬菜对Pb、Cd、Cu、Zn的富集可分为高富集、中富集和低富集,针对不同的土壤污染程度,可以选择不同富集系数的蔬菜种植;(2)提高土壤pH值,有助于降低蔬菜中P... 用通过大田调查的方法,研究了影响蔬菜中Pb、Cd、Cu、Zn含量的因素。结果表明:(1)蔬菜对Pb、Cd、Cu、Zn的富集可分为高富集、中富集和低富集,针对不同的土壤污染程度,可以选择不同富集系数的蔬菜种植;(2)提高土壤pH值,有助于降低蔬菜中Pb、Cd、Cu、Zn的含量;调节土壤阳离子交换量、有机质含量和粘粒含量应注意适度,过高会导致相反的结果;(3)土壤Pb、Cd、Cu、Zn之间的相互关系较为复杂,Cu与Zn之间具有相互的拮抗作用,Cu对Pb的吸收具有促进作用。 展开更多
关键词 蔬菜 含量 影响因素 土壤污染 阳离子 交换量 有机质 粘粒 含量
下载PDF
The WRKY Gene Family in Rice (Oryza sativa) 被引量:107
3
作者 christian A. Ross Yue Liu Qingxi J. Shen 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2007年第6期827-842,共16页
WRKYgenee encode transcription factors that are Involved In the regulation of various biological processes. These zinc-finger proteins, especially those members mediating stress responses, are uniquely expanded In pla... WRKYgenee encode transcription factors that are Involved In the regulation of various biological processes. These zinc-finger proteins, especially those members mediating stress responses, are uniquely expanded In plants. To facilitate the study of the evolutionary history and functions of this eupergene family, we performed an exhaustive search for WRKY genes using HMMER and a Hidden Markov Model that was specifically trained for rice. This work resulted In a comprehensive list of WRKYgene models In Oryza sativa L. eep. indica and L. eep. Japonica. Mapping of these genes to Individual chromosomes facilitated elimination of the redundant, leading to the Identification of 98 WRKYgenee In Japonica and 102 In indica rice. These genes were further categorized according to the number and structure of their zinc-finger domains. Based on a phylogenetlc tree of the conserved WRKY domains and the graphic display of WRKY loci on corresponding indica and Japonica chromosomes, we Identified possible WRKY gene duplications within, and losses between the two closely related rice subspecies. Also reviewed are the roles of WRKY genes In disease resistance and responses to salicylic acid and Jaemonlc acid, seed development and germination mediated by glbberelllns, other developmental processes Including senescence, and responses to ablotlc stresses and abeclelc acid In rice and other plants. The signaling pathways mediating WRKY gene expreeelon are also discussed. 展开更多
关键词 gene family INDICA JAPONICA Oryza sativa RICE WRKY.
原文传递
欧洲新生儿呼吸窘迫综合征防治共识指南:2016版 被引量:97
4
作者 DavidG.Sweet Virgilio Carnielli +9 位作者 Gorm Greisen Mikko Hallman Eren Ozek Richard Plavka Ola Didrik Saugstad Umberto Simeoni christian P. Speer Maximo Vento Gerard H. A. Visser Henry L. Halliday 《中华儿科杂志》 CAS CSCD 北大核心 2017年第3期169-176,共8页
新生儿呼吸窘迫综合征(RDS)是早产儿的重要疾病,尽管治疗手段不断成熟,低龄早产儿存活率逐渐增高,但支气管肺发育不良(BPD)发病率也随之升高,其中部分原因是减少了出生后激素的使用.2006年以来,来自欧洲许多国家的新生儿专家每3年... 新生儿呼吸窘迫综合征(RDS)是早产儿的重要疾病,尽管治疗手段不断成熟,低龄早产儿存活率逐渐增高,但支气管肺发育不良(BPD)发病率也随之升高,其中部分原因是减少了出生后激素的使用.2006年以来,来自欧洲许多国家的新生儿专家每3年一次回顾最新文献,就RDS或有RDS风险早产儿的防治达成共识,立志于改善欧洲新生儿的预后.欧洲RDS防治指南2007年开始发布,2010年和2013年进行了更新,期间获得了欧洲围产医学学会的大力支持.RDS是由于肺表面活性物质(PS)缺乏导致生后早期出现呼吸窘迫,典型临床表现随着防治手段的改进发生了巨大变化. 展开更多
关键词 新生儿呼吸窘迫综合征 防治指南 欧洲 支气管肺发育不良 肺表面活性物质 早产儿 RDS 医学学会
原文传递
Challenge and Opportunity in Improving Fertilizer-nitrogen Use Efficiency of Irrigated Rice in China 被引量:87
5
作者 Roland Buresh christian Witt 《Agricultural Sciences in China》 CAS CSCD 2002年第7期776-785,共10页
Today, about 30% of world nitrogen (N) fertilizer is consumed by China. Rice crops in China consume about 37% of the total N fertilizer used for rice production in the world. Average rate of N application for rice pro... Today, about 30% of world nitrogen (N) fertilizer is consumed by China. Rice crops in China consume about 37% of the total N fertilizer used for rice production in the world. Average rate of N application for rice production in China is high and fertilizer-N use efficiency is low compared with other major rice growing countries. Research progresses have been made internationally and domestically on the application method, fertilizer-N sources, computer-based decision support systems, and real-time N management in order 展开更多
关键词 Fertilizer-nitrogen use efficiency Nitrogen management RICE
下载PDF
云南瑞丽物质滥用调查与社区干预 被引量:80
6
作者 李建华 朱华 +3 位作者 万文鹏 石青 刘德全 Keith Emrich christian J.Kroll 《中国心理卫生杂志》 CSSCI CSCD 北大核心 1993年第6期257-259,共3页
作者在云南瑞丽的四所中学和32个自然村进行了成瘾物质使用情况调查。结果发现,中学生中18.7%吸烟,1.10%的学生平均每天摄入纯酒精75g 以上,0.99%的人曾使用过鸦片,0.94%曾使用过海洛英。村民中吸烟者占43.7%,8.39%的人平均每天摄入纯酒... 作者在云南瑞丽的四所中学和32个自然村进行了成瘾物质使用情况调查。结果发现,中学生中18.7%吸烟,1.10%的学生平均每天摄入纯酒精75g 以上,0.99%的人曾使用过鸦片,0.94%曾使用过海洛英。村民中吸烟者占43.7%,8.39%的人平均每天摄入纯酒精75g 以上,12.3%曾使用过鸦片,7.8%曾使用过海洛英。在调查的基础上,选择4个自然村开始实施为期三年以社区为基础的药物滥用预防干预计划,一年半后中期评估的结果令人鼓舞,药物依赖者中39.4%完全戒除了海洛英。 展开更多
关键词 社区干预 评估 吸毒 药物滥用
下载PDF
比利时马铃薯晚疫病预警系统及其在我国的应用 被引量:77
7
作者 谢开云 车兴壁 +1 位作者 christian Ducatillon Francois Serneels 《中国马铃薯》 2001年第2期67-71,共5页
利用晚疫病预测预报模型可以准确地预报晚疫病发生的时间 ,指导薯农适时适量地用药。比利时利用CARAH模型 15年来取得了很好的效果 ,消除了由晚疫病造成的损失并减少了杀菌剂的施用量。本文详细地介绍了该模型的起因、数据的收集和具体... 利用晚疫病预测预报模型可以准确地预报晚疫病发生的时间 ,指导薯农适时适量地用药。比利时利用CARAH模型 15年来取得了很好的效果 ,消除了由晚疫病造成的损失并减少了杀菌剂的施用量。本文详细地介绍了该模型的起因、数据的收集和具体的运用 ,并根据此模型在中国的初步应用提出了利用该预测预报的建议。 展开更多
关键词 马铃薯 晚疫病 预测预报 预警系统 应用
下载PDF
2008中西方BNP专家共识 被引量:77
8
作者 Alan Maise christian Mueller +7 位作者 W. Frank Peacock Gerasimos Filippatos Hu Dayi 胡大一(主译) 刘梅颜(主译) 吴寸草(翻译) 王博雅(翻译) 黄睿(翻译) 《中国医药导刊》 2009年第10期1628-1637,共10页
1.前言 2008年6月,来自中国、美国、欧洲的急诊科、心血管科、实验室及内科临床专家相聚在中国上海。
关键词 BNP 2008 中西方 专家共识
下载PDF
电力系统主动解列控制方法的研究 被引量:67
9
作者 沈沉 吴佳耘 +3 位作者 乔颖 卢强 刘前进 christian Rehtanz 《中国电机工程学报》 EI CSCD 北大核心 2006年第13期1-6,共6页
解列是电力系统在受到大的干扰,系统完整性无法保持的情况下将系统分解成几个孤岛的控制。以在线计算、全局控制、协调动作为特点的主动解列控制是一个重要的研究方向。文中分析了主动解列控制需要回答的关键问题,介绍了一种以“搜索加... 解列是电力系统在受到大的干扰,系统完整性无法保持的情况下将系统分解成几个孤岛的控制。以在线计算、全局控制、协调动作为特点的主动解列控制是一个重要的研究方向。文中分析了主动解列控制需要回答的关键问题,介绍了一种以“搜索加校验”为基本思路的主动解列策略求解方案,提出了合理解列策略的评价指标,最后指出了在主动解列研究中应当首先开展工作的几个方向。 展开更多
关键词 电力系统安全 解列控制 搜索 校验
下载PDF
昆明市蔬菜及其土壤中铅、镉、铜和锌含量水平及污染评价 被引量:55
10
作者 祖艳群 李元 +3 位作者 陈海燕 陈建军 Marianne Guhur christian Schvartz 《云南环境科学》 2003年第B03期55-57,共3页
对昆明市蔬菜及其土壤中铅、镉、铜和锌含量水平进行了初步的调查并对其土壤污染进行了评价 ,结果表明 :蔬菜土壤重金属Pb、Cd、Cu、Zn均存在一定程度的污染 ,其中Pb、Zn为轻污染 ,Cd、Cu为中污染 ,土壤重金属综合评价为中污染。蔬菜可... 对昆明市蔬菜及其土壤中铅、镉、铜和锌含量水平进行了初步的调查并对其土壤污染进行了评价 ,结果表明 :蔬菜土壤重金属Pb、Cd、Cu、Zn均存在一定程度的污染 ,其中Pb、Zn为轻污染 ,Cd、Cu为中污染 ,土壤重金属综合评价为中污染。蔬菜可食部分Pb、Cd、Zn的含量均超过国家食品卫生标准和绿色蔬菜标准 ,依次为Pb、Cu、Cd、Zn。 展开更多
关键词 蔬菜 土壤 重金属 污染 昆明市 污染评价
下载PDF
Clinical characteristics and outcome of a cohort of 101 patients with hepatocellular carcinoma 被引量:60
11
作者 christian Rabe Tillmann Pilz +4 位作者 Christoph Klostermann Marc Berna Hans H.Schild Tilman Sauerbruch Wolfgang H.Caselmann 《World Journal of Gastroenterology》 SCIE CAS CSCD 2001年第2期208-215,共8页
AIM: To conduct a cohort study of 101 patients with hepatocellular carcinoma (HCC) presenting to a tertiary care medical referral center in Germany between 1997 and 1999. METHODS AND RESULTS: Data were retrospectively... AIM: To conduct a cohort study of 101 patients with hepatocellular carcinoma (HCC) presenting to a tertiary care medical referral center in Germany between 1997 and 1999. METHODS AND RESULTS: Data were retrospectively analyzed by chart review. In 95 cases (72 males and 23 females) sufficient data were available for analysis. Twenty five (29%) of 85 patients were HBsAg or anti HBc positive, 21/85 (25%) were anti HCV positive, and 6/85 (7%) were positive for both HBV and HCV-markers. Age was significantly lower in HBV positive patients than in the other two groups. Thirty one (34%) of 90 patients had histories of alcohol abuse. In 79/94 (84%) patients, cirrhosis was diagnosed. Of these cirrhotic patients, 29/79 (37%) belonged to Child Pugh's group (CHILD) A, 32/79 (40%) to CHILD B, and 18/79 (23%) to CHILD C. AFP was elevated in 61/91 (67%) patients. A single tumor nodule was found in 38/94 (40%), more than one nodule in 31/94 (34%), and 25/94 (26%) had a diffusely infiltrating tumor, i.e. the tumor margins could not be seen on imaging procedures. Portal vein thrombosis was present in 19/94 (20%). Imaging data consistent with lymph node metastases were found in 10/92 (11%), while distant metastases were found in 8/93 (9%). According to Okuda 28/94 (30%) were grouped to stage I, 53/94 (56%) were grouped to stage II, and 13/94 (14%) were grouped to stage II. Survival data were available for 83 patients. The Kaplan-Meier estimate for median survival was 8 4 months. Factors influencing survival were the Okuda score, the presence of portal vein thrombosis, and the presence of ascites. The presence of non complicated liver cirrhosis by itself, distant metastases, or infection with hepatitis viruses did not influence survival. AFP positivity by itself did not influence survival, though patients with an AFP value greater than 100 microg/L did experience shortened survival. Treatment besides tamoxifen or supportive care was associated with prolonged survival. The influence of therapy on survival was most pronounced in Okuda 展开更多
关键词 Adult Aged Aged 80 and over Carcinoma Hepatocellular Cohort Studies Female Germany Hepatitis B Hepatitis C Humans Liver Cirrhosis Alcoholic Liver Neoplasms Male Middle Aged Research Support Non-U.S. Gov't Retrospective Studies Risk Factors Survival Analysis
下载PDF
Regulation of hepatic blood flow:The hepatic arterial buffer response revisited 被引量:58
12
作者 christian Eipel Kerstin Abshagen Brigitte Vollmar 《World Journal of Gastroenterology》 SCIE CAS CSCD 2010年第48期6046-6057,共12页
The interest in the liver dates back to ancient times when it was considered to be the seat of life processes. The liver is indeed essential to life,not only due to its complex functions in biosynthesis,metabolism and... The interest in the liver dates back to ancient times when it was considered to be the seat of life processes. The liver is indeed essential to life,not only due to its complex functions in biosynthesis,metabolism and clearance,but also its dramatic role as the blood volume reservoir. Among parenchymal organs,blood flow to the liver is unique due to the dual supply from the portal vein and the hepatic artery. Knowledge of the mutual communication of both the hepatic artery and the portal vein is essential to understand hepatic physiology and pathophysiology. To distinguish the individual importance of each of these inflows in normal and abnormal states is still a challenging task and the subject of on-going research. A central mechanism that controls and allows constancy of hepatic blood flow is the hepatic arterial buffer response. The current paper reviews the relevance of this intimate hepatic blood flow regulatory system in health and disease. We exclusively focus on the endogenous interrelationship between the hepatic arterial and portal venous inflow circuits in liver resection and transplantation,as well as inflammatory and chronic liver diseases. We do not consider the hepatic microvascular anatomy,as this has been the subject of another recent review. 展开更多
关键词 HEPATIC BLOOD flow HEPATIC ARTERIAL BUFFER response LIVER
下载PDF
基于Peerceptiv互评系统的英语写作同伴反馈效果研究 被引量:53
13
作者 高瑛 张福慧 +1 位作者 张绍杰 christian D.Schunn 《外语电化教学》 CSSCI 北大核心 2018年第2期3-9,67,共8页
同伴互评作为教学手段的应用价值毋庸置疑。但是,同伴互评的效果与作者和评者的二语水平互动密切相关。文章以能力对同伴互评影响理论模型为依据,以基于Peerceptiv同伴互评系统的30篇学术写作文本一、二稿及1927条同伴反馈评语为研究语... 同伴互评作为教学手段的应用价值毋庸置疑。但是,同伴互评的效果与作者和评者的二语水平互动密切相关。文章以能力对同伴互评影响理论模型为依据,以基于Peerceptiv同伴互评系统的30篇学术写作文本一、二稿及1927条同伴反馈评语为研究语料,分析同伴互评的实施效果。结果显示,反馈评语与文本修改提高率总体呈正相关;作者和评者二语水平的非对称组合评语量最大,最有利于文本修改,是提高反馈效果的最佳组合方式。 展开更多
关键词 同伴互评 反馈评语 文本修改 二语水平
原文传递
Endoscopic ultrasound elastography for evaluation of lymph nodes and pancreatic masses:A multicenter study 被引量:48
14
作者 Marc Giovannini Botelberge Thomas +16 位作者 Bories Erwan Pesenti christian Caillol Fabrice Esterni Benjamin Monges Geneviève Arcidiacono Paolo Deprez Pierre Yeung Robert Schimdt Walter Schrader Hanz Szymanski Carl Dietrich Christoph Eisendrath Pierre Van Laethem Jean-Luc Devière Jacques Vilmann Peter Saftoiu Andrian 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第13期1587-1593,共7页
AIM:To evaluate the ability of endoscopic ultrasound(EUS) elastography to distinguish benign from malignant pancreatic masses and lymph nodes.METHODS:A multicenter study was conducted and included 222 patients who und... AIM:To evaluate the ability of endoscopic ultrasound(EUS) elastography to distinguish benign from malignant pancreatic masses and lymph nodes.METHODS:A multicenter study was conducted and included 222 patients who underwent EUS examination with assessment of a pancreatic mass(n=121) or lymph node(n=101).The classification as benign or malignant,based on the real time elastography pattern,was compared with the classif ication based on the B-mode EUS images and with the fi nal diagnosis obtained by EUS-guided fi ne needle aspiration(EUS-FNA) and/or by surgical pathology.An interobserver study was performed.RESULTS:The sensitivity and specificity of EUS elastography to differentiate benign from malignant pancreatic lesions are 92.3% and 80.0%,respectively,compared to 92.3% and 68.9%,respectively,for the conventional B-mode images.The sensitivity and specificity of EUS elastography to differentiate benign from malignant lymph nodes was 91.8% and 82.5%,respectively,compared to 78.6% and 50.0%,respectively,for the B-mode images.The kappa coefficient was 0.785 for the pancreatic masses and 0.657 for the lymph nodes.CONCLUSION:EUS elastography is superior compared to conventional B-mode imaging and appears to be able to distinguish benign from malignant pancreatic masses and lymph nodes with a high sensitivity,specificity and accuracy.It might be reserved as a second line examination to help characterise pancreatic masses after negative EUS-FNA and might increase the yield of EUS-FNA for lymph nodes. 展开更多
关键词 Endoscopic ultrasound Elasticity coefficient ELASTOGRAPHY Pancreatic mass Lymph node
下载PDF
Surgical outcome after docetaxel-based neoadjuvant chemotherapy in locally-advanced gastric cancer 被引量:43
15
作者 Roberto Biffi Nicola Fazio +10 位作者 Fabrizio Luca Antonio Chiappa Bruno Andreoni Maria Giulia Zampino Arnaud Roth Jan christian Schuller Giancarla Fiori Franco Orsi Guido Bonomo Cristiano Crosta Olivier Huber 《World Journal of Gastroenterology》 SCIE CAS CSCD 2010年第7期868-874,共7页
AIM:To investigate feasibility,morbidity and surgical mortality of a docetaxel-based chemotherapy regimen randomly administered before or after gastrectomy in patients suffering from locally-advanced resectable gastri... AIM:To investigate feasibility,morbidity and surgical mortality of a docetaxel-based chemotherapy regimen randomly administered before or after gastrectomy in patients suffering from locally-advanced resectable gastric cancer.METHODS:Patients suffering from locally-advanced(T3-4 any N M0 or any T N1-3 M0)gastric carcinoma,staged with endoscopic ultrasound,bone scan,computed tomography,and laparoscopy,were assigned to receive four 21 d/cycles of TCF(docetaxel 75 mg/m 2 day 1,cisplatin 75 mg/m 2 day 1,and fluorouracil 300 mg/m 2 per day for days 1-14),either before(Arm A)or after(Arm B)gastrectomy.Operative morbidity,overall mortality,and severe adverse events were compared by intention-to-treat analysis.RESULTS:From November 1999 to November 2005,70 patients were treated.After preoperative TCF(Arm A),thirty-two(94%)resections were performed,85% of which were R0.Pathological response was complete in 4 patients(11.7%),and partial in 18(55%).No surgical mortality and 28.5%morbidity rate were observed,similar to those of immediate surgery arm(P= 0.86).Serious chemotherapy adverse events tended to be more frequent in arm B(23%vs 11%,P=0.07),with a single death per arm.CONCLUSION:Surgery following docetaxel-based chemotherapy was safe and with similar morbidity to immediate surgery in patients with locally-advanced resectable gastric carcinoma. 展开更多
关键词 Gastric cancer DOCETAXEL Neoadjuvant chemotherapy LAPAROSCOPY Endoscopic ultrasonography MORBIDITY
下载PDF
Overlap syndromes among autoimmune liver diseases 被引量:42
16
作者 christian Rust Ulrich Beuers 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第21期3368-3373,共6页
The three major immune disorders of the liver are autoimmune hepatitis(AIH),primary biliary cirrhosis(PBC) and primary sclerosing cholangitis(PSC).Variant forms of these diseases are generally called overlap syndromes... The three major immune disorders of the liver are autoimmune hepatitis(AIH),primary biliary cirrhosis(PBC) and primary sclerosing cholangitis(PSC).Variant forms of these diseases are generally called overlap syndromes,although there has been no standardised definition.Patients with overlap syndromes present with both hepatitic and cholestatic serum liver tests and have histological features of AIH and PBC or PSC.The AIH-PBC overlap syndrome is the most common form,affecting almost 10% of adults with AIH or PBC.Single cases of AIH and autoimmune cholangitis(AMA-negative PBC) overlap syndrome have also been reported.The AIH-PSC overlap syndrome is predominantly found in children,adolescents and young adults with AIH or PSC.Interestingly,transitions from one autoimmune to another have also been reported in a minority of patients,especially transitions from PBC to AIH-PBC overlap syndrome.Overlap syndromes show a progressive course towards liver cirrhosis and liver failure without treatment.Therapy for overlap syndromes is empiric,since controlled trials are not available in these rare disorders.Anticholestatic therapy with ursodeoxycholic acid is usually combined with immunosuppressive therapy with corticosteroids and/or azathioprine in both AIH-PBC and AIH-PSC overlap syndromes.In end-stage disease,liver transplantation is the treatment of choice. 展开更多
关键词 Autoimmune hepatitis Immunosuppressive agents Primary biliary cirrhosis Primary sclerosing cholangitis Ursodeoxycholic acid
下载PDF
Assessment of metastatic liver disease in patients with primary extrahepatic tumors by contrast-enhanced sonography versus CT and MRI 被引量:39
17
作者 Christoph F Dietrich Wolfgang Kratzer +10 位作者 Deike Strobel Etienne Danse Robert Fessl Alfred Bunk Udo Vossas Karlheinz Hauenstein Wilhelm Koch Wolfgang Blank Matthijs Oudkerk Dietbert Hahn christian Greis 《World Journal of Gastroenterology》 SCIE CAS CSCD 2006年第11期1699-1705,共7页
AIM: To evaluate contrast-enhanced ultrasonography (CEUS) using SonoVue in the detection of liver metastases in patients with known extrahepatic primary tumors versus the combined gold standard comprising CT, MRI a... AIM: To evaluate contrast-enhanced ultrasonography (CEUS) using SonoVue in the detection of liver metastases in patients with known extrahepatic primary tumors versus the combined gold standard comprising CT, MRI and clinical/histological data. METHODS: It is an international multicenter study, and there were 12 centres and 125 patients (64 males, 61 females, aged 59 ± 11 years) involved, with 102 patients per protocol. Primary tumors were colorectal in 35%, breast in 27%, pancreatic in 17% and others in 21%. CEUS using SonoVue was employed with a Iow-mechanical-index technique and contrast-specific software using Siemens Elegra, Philips HDI 5000 and Acuson Sequoia; continuous scanning for at least five minutes. RESULTS: CEUS with SonoVue increased significantly the number of focal liver lesions detected versus unenhanced sonography. In 31.4% of the patients, more lesions were found after contrast enhancement. The total numbers of lesions detected were comparable with CEUS (55), triple-phase spiral CT (61) and HRI with a liverspecific contrast agent (53). Accuracy of detection of metastatic disease (i.e. at least one metastatic lesion) was significantly higher for CEUS (91.2%) than for unenhanced sonography (81.4%) and was similar to that of triple-phase spiral CT (89.2 %). In 53 patients whose CEUS examination was negative, a follow-up examination 3-6 months later confirmed the absence of metastatic lesions in 50 patients (94.4%). CONCLUSION: CEUS is proved to be reliable in the detection of liver metastases in patients with known extrahepatic primary tumors and suspected liver lesions. 展开更多
关键词 CT MRI METASTASIS Detection SONOVUE
下载PDF
Characterization of focal liver lesions with SonoVue~-enhanced sonography: International multicenter-study in comparison to CT and MRI 被引量:37
18
作者 Hervé Trillaud Jean-Michel Bruel +7 位作者 Pierre-Jean Valette Valérie Vilgrain Gérard Schmutz Raymond Oyen Wieslaw Jakubowski Jan Danes Vlastimil Valek christian Greis 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第30期3748-3756,共9页
AIM: To evaluate in a multicenter study whether the sonographic characterization of focal liver lesions can be improved using SonoVue-enhancement; and to compare this method with computed tomography (CT) and magnet... AIM: To evaluate in a multicenter study whether the sonographic characterization of focal liver lesions can be improved using SonoVue-enhancement; and to compare this method with computed tomography (CT) and magnetic resonance imaging (MRI). METHODS: One hundred and thirty four patients withone focal liver lesion detected in baseline ultrasound (US) were examined with conventional US, contrastenhanced US (n = 134), contrast-enhanced CT (n = 115) and/or dynamic contrast-enhanced MRI (n = 70). The lesions were classified as malignant, benign or indeterminate and the type of lesion was determined. The final diagnosis based on the combined information of all imaging examinations, clinical information and histology (n = 32) was used. Comparisons were made to see whether the addition of contrast-enhanced US led to the improvement of the characterization of doubtful focal liver lesions.RESULTS: In comparison with unenhanced US, SonoVue markedly improves sensitivity and specificity for the characterization (malignant/benign) of focal liver lesions. In comparison with CT and/or dynamic MRI, SonoVue -enhanced sonography applied for characterization of focal liver lesions was 30.2% more sensitive in the recognition of malignancy and 16.1% more specific in the exclusion of malignancy and overall 22.9% more accurate. In the subgroup with confirmative histology available (n = 30), sensitivity was 95.5% (CEUS), 72.2% (CT) and 81.8% (MRI), and specificity was 75.0% (CEUS), 37.5% (CT) and 42.9% (MRI). The sensitivity and specificity of CEUS for the identification of focal nodular hyperplasia (FNH) and hemangiomas was 100% and 87%, resulting in an accuracy of 94.5%.CONCLUSION: SonoVue-enhanced sonography emerges as the most sensitive, ost specific and thus most accurate imaging modality for the characterization of focal liver lesions. 展开更多
关键词 Contrast-enhanced sonography Contrastmedia Dynamic sonography Liver lesion Liverdisease LIVER Oncologic imaging SONOGRAPHY
下载PDF
抗氧化剂一、二级预防随机试验中的死亡率系统回顾及汇总分析 被引量:36
19
作者 Goran Bjelakovic Dimitrinka Nikolova +3 位作者 Lise Lotte Gluud Rose G. Simonetti christian Gluud 顾佳(译) 《美国医学会杂志(中文版)》 2007年第5期278-291,共14页
背景:抗氧化剂正用于多种疾病的预防。 目的:评估补充抗氧化剂对一、二级预防随机临床试验参试者死亡率的影响。数据来源及试验选择:检索2005年10月前的电子数据库以及发表的文献目录。所有于成人中进行的、比较单独或联合使用β胡... 背景:抗氧化剂正用于多种疾病的预防。 目的:评估补充抗氧化剂对一、二级预防随机临床试验参试者死亡率的影响。数据来源及试验选择:检索2005年10月前的电子数据库以及发表的文献目录。所有于成人中进行的、比较单独或联合使用β胡萝卜素、维生素A、维生素C(抗坏血酸)、维生素E及硒剂的安慰剂或空白治疗对照随机试验均纳入分析。使用随机、盲法及随访作为评估入选试验偏倚的指标。采用随机效应分析法分析抗氧化剂对全因死亡率的影响,结果以相对危险度(relative risk,RR)及其95%可信区间(confidence interval,CI)表示。采用汇总回归评估试验协变量的影响。 数据提取:共入选68项随即试验,包括232606例参试者(385篇文章)。 数据整合:将所有低和高偏倚风险抗氧化剂试验汇总后发现,抗氧化剂对死亡率无显著影响(RR,1.02;95%CI,0.98~1.06)。多变量汇总回归分析表明,低偏倚风险试验(RR,1.16;95%CI,1.05~1.29)和硒剂(RR,0.998;95%CI,0.997~0.9995)与死亡率显著相关。在包括180938例参试者在内的47项低偏倚试验中,补充抗氧化剂显著增加死亡率(RR,1.05;95%CI,1.02~1.08)。排除硒剂试验后,在低偏倚风险试验中,β胡萝卜素(RR,1.07;95%CI,1.02~1,11)、维生素A(RR,1.16;95%CI,1.10~1.24)以及维生素E(RR,1.04;95%CI,1.01~1.07)单独或联合使用均显著增加死亡率。维生素C及硒剂对死亡率无显著影响。 结论:β胡萝卜素、维生素A及维生素E治疗可能增加死亡率。维生素C和硒剂对死亡率的影响需要进一步研究。 展开更多
关键词 全因死亡率 随机试验 抗氧化剂 二级预防 汇总分析 系统回顾 Β胡萝卜素 维生素A
下载PDF
矩阵变换器的建模与仿真(英文) 被引量:26
20
作者 刘芙蓉 Klumpner christian Blaabjerg Frede 《中国电机工程学报》 EI CSCD 北大核心 2005年第9期62-67,共6页
该文着重讨论矩阵变换器的建模与仿真。文中给出了矩阵变换器的两种模型:基于间接空间矢量调制法的模型和基于功率守恒方程的模型,详细介绍了这两种模型建立的理论基础和建立过程,并结合这两种模型在研究不同问题时的仿真结果,说明模型... 该文着重讨论矩阵变换器的建模与仿真。文中给出了矩阵变换器的两种模型:基于间接空间矢量调制法的模型和基于功率守恒方程的模型,详细介绍了这两种模型建立的理论基础和建立过程,并结合这两种模型在研究不同问题时的仿真结果,说明模型难有绝对的好坏之分,应针对不同的问题采用不同的模型。文中同时也介绍了矩阵变换器建模中应注意的问题及技巧,为深入进行矩阵变换器的仿真研究提供了参考和借鉴。 展开更多
关键词 矩阵变换器 建模与仿真 守恒方程 空间矢量 理论基础 详细介绍 仿真结果 仿真研究 模型 调制法
下载PDF
上一页 1 2 154 下一页 到第
使用帮助 返回顶部