期刊文献+
共找到4,037篇文章
< 1 2 202 >
每页显示 20 50 100
青少年抑郁情绪的发展轨迹:界定亚群组及其影响因素 被引量:53
1
作者 侯金芹 陈祉妍 《心理学报》 CSSCI CSCD 北大核心 2016年第8期957-968,共12页
本研究意在分性别考察中国青少年抑郁情绪的发展轨迹及其影响因素。785名男生和859名女生参加了3轮追踪研究, 初始测量阶段的年龄跨度为10~16岁, 平均年龄分别为12.99 ± 1.84和12.96 ± 1.87岁。采用流调中心抑郁量表(CES-D... 本研究意在分性别考察中国青少年抑郁情绪的发展轨迹及其影响因素。785名男生和859名女生参加了3轮追踪研究, 初始测量阶段的年龄跨度为10~16岁, 平均年龄分别为12.99 ± 1.84和12.96 ± 1.87岁。采用流调中心抑郁量表(CES-D)简版测量青少年的抑郁情绪。模型拟合的结果显示男女生的抑郁情绪在10~19岁时段皆呈线性增长趋势, 其中男生分为两个亚群组, 人际关系解释了部分变异; 女生分为4个亚群组, 学业压力和人际关系均解释了部分变异。 展开更多
关键词 抑郁情绪 发展轨迹 性别差异 亚群组 风险因素
下载PDF
多样化团队中的断裂带:形成、演化和效应研究 被引量:26
2
作者 王端旭 薛会娟 《浙江大学学报(人文社会科学版)》 CSSCI 北大核心 2009年第5期122-128,共7页
团队断裂带是由成员多样化特征的组合而引发的群体分化,这一概念为深入理解多样化的效应提供了新的视角。团队断裂带形成的理论依据是社会分类理论及同性相吸范式。在团队的发展过程中,断裂带的特征类型和强度均会发生动态变化。相应地... 团队断裂带是由成员多样化特征的组合而引发的群体分化,这一概念为深入理解多样化的效应提供了新的视角。团队断裂带形成的理论依据是社会分类理论及同性相吸范式。在团队的发展过程中,断裂带的特征类型和强度均会发生动态变化。相应地,断裂带的效应也会有所不同。团队断裂带是把"双刃剑",它通过影响团队凝聚力、团队沟通和团队冲突对团队效能发挥作用,并且其效应的强弱受任务互依性、团队的知识管理系统和外部领导者的管理等情境因素的调节。针对断裂带的复杂效应,团队管理者应采取多种措施为断裂带架桥,以尽可能协调子群之间的关系,趋利避害。 展开更多
关键词 团队多样化 团队断裂带 子群 效应
下载PDF
4次对称群S_4的子群个数及其证明 被引量:17
3
作者 孙自行 崔方达 《阜阳师范学院学报(自然科学版)》 2005年第4期13-16,28,共5页
使用Lagrange定理及n次对称群的基本概念证明了4次对称群存在且只存在30个子群,并给出了每个子 群.其中,除去两个平凡的子群,另有9个2阶循环群;4个3阶循环群;3个4阶循环群;4个Klein4元群;4个S3(在 同构意义之下);3个8阶子群以及1个12... 使用Lagrange定理及n次对称群的基本概念证明了4次对称群存在且只存在30个子群,并给出了每个子 群.其中,除去两个平凡的子群,另有9个2阶循环群;4个3阶循环群;3个4阶循环群;4个Klein4元群;4个S3(在 同构意义之下);3个8阶子群以及1个12阶子群. 展开更多
关键词 4次对称群 子群 LAGRANGE定理 群的阶 元索的阶 循环置换
下载PDF
消化性溃疡诊治中的几个问题 被引量:16
4
作者 杨健 陈高红 王汉斌 《国际内科学杂志》 CAS 2009年第8期441-444,共4页
消化性溃疡是一种常见病、多发病。目前绝大多数可以内科治愈,但在消化性溃疡的发病机制、分型及抗复发等方面还存在一些问题。本文介绍消化性溃疡的诊治进展。
关键词 溃疡/消化性 发病机制 幽门螺杆菌 诊治 分型
下载PDF
功能性消化不良不同亚型临床特征研究 被引量:16
5
作者 古巧燕 张军 冯义朝 《胃肠病学和肝病学杂志》 CAS 2015年第3期330-332,共3页
目的探讨功能性消化不良不同亚型患者精神心理因素、睡眠质量、生活质量方面的差异性。方法功能性消化不良患者120例,分为上腹痛综合征(epigastric pain syndrome,EPS)、餐后不适综合征(postprandial distress syndrome,PDS)和重叠型三... 目的探讨功能性消化不良不同亚型患者精神心理因素、睡眠质量、生活质量方面的差异性。方法功能性消化不良患者120例,分为上腹痛综合征(epigastric pain syndrome,EPS)、餐后不适综合征(postprandial distress syndrome,PDS)和重叠型三组,均进行Zung氏焦虑自评量表、Zung氏抑郁自评量表、SF-36生活质量调查量表和匹茨堡睡眠质量指数量表评定。结果 (1)三组间在焦虑患病率、抑郁患病率、睡眠障碍患病率上比较差异均有统计学意义(P<0.05);(2)三组患者在生理功能、情感职能、活力、精神健康、社会功能、躯体疼痛、总体健康方面比较差异有统计学意义(P<0.05),其中重叠型组评分最高;在生理职能方面三组之间差异无统计学意义(P>0.05)。结论功能性消化不良不同亚型患者焦虑、抑郁患病率,睡眠障碍率不同,生活质量有一定差异,针对功能性消化不良不同亚型患者的临床特征,有助于制定有效的治疗方案,对于提高功能性消化不良患者的生活质量有重要意义。 展开更多
关键词 功能性消化不良 亚型 特征
下载PDF
On solubility and supersolubility of some classes of finite groups 被引量:10
6
作者 SHUM Kar Ping SKIBA Alexander N. 《Science China Mathematics》 SCIE 2009年第2期272-286,共15页
AbstractLet G be a finite group and H a subgroup of G. Then H is said to be S-permutable in G if HP = PH for all Sylow subgroups P of G. Let H sG be the subgroup of H generated by all those subgroups of H which are S-... AbstractLet G be a finite group and H a subgroup of G. Then H is said to be S-permutable in G if HP = PH for all Sylow subgroups P of G. Let H sG be the subgroup of H generated by all those subgroups of H which are S-permutable in G. Then we say that H is S-embedded in G if G has a normal subgroup T and an S-permutable subgroup C such that T ∩ H ? H sG and HT = C.Our main result is the followingTheorem AA group G is supersoluble if and only if for every non-cyclic Sylow subgroup P of the generalized Fitting subgroup F*(G) of G, at least one of the following holds: Every maximal subgroup of P is S-embedded in G.Every cyclic subgroup H of P with prime order or order 4 (if P is a non-abelian 2-group and H ? Z ∞ (G)) is S-embedded in G. 展开更多
关键词 S-permutable subgroups S-embedded subgroups saturated formations generalized Fitting subgroups supersoluble groups 20D10 20D20 20D25
原文传递
Finite groups with systems of Σ-embedded subgroups 被引量:14
7
作者 GUO WenBin SKIBA Alexander N 《Science China Mathematics》 SCIE 2011年第9期1909-1926,共18页
In recent years,a series of papers about cover-avoiding property of subgroups appeared and all the studies were connected with chief factors of a finite group.However,about the cover-avoiding property of subgroups for... In recent years,a series of papers about cover-avoiding property of subgroups appeared and all the studies were connected with chief factors of a finite group.However,about the cover-avoiding property of subgroups for non-chief factor,there is no study up to now.The purpose of this paper is to build the theory.Let A be a subgroup of a finite group G and Σ:G0≤G1≤…≤Gn some subgroup series of G.Suppose that for each pair(K,H) such that K is a maximal subgroup of H and G i 1 K < H G i for some i,either A ∩ H = A ∩ K or AH = AK.Then we say that A is Σ-embedded in G.In this paper,we study the finite groups with given systems of Σ-embedded subgroups.The basic properties of Σ-embedded subgroups are established and some new characterizations of some classes of finite groups are given and some known results are generalized. 展开更多
关键词 finite group ∑-embedded subgroups ∑p-embedded subgroup soluble group supersoluble group p-nilpotent group saturated formation
原文传递
人群的自然和社会属性分类下PM_(2.5)对心血管疾病的影响 被引量:14
8
作者 龚天宜 孙兆彬 +1 位作者 张小玲 王式功 《中国环境科学》 EI CAS CSCD 北大核心 2019年第3期1289-1298,共10页
为了研究人群在自然属性和社会属性分类下的效应修饰作用,利用2005~2011年北京市大气PM_(2.5)日均浓度、气象要素及循环系统疾病每日死亡人数数据,根据不同年龄、性别及学历将人群分组,采用时间序列的半参数广义相加模型(GAM),定量评... 为了研究人群在自然属性和社会属性分类下的效应修饰作用,利用2005~2011年北京市大气PM_(2.5)日均浓度、气象要素及循环系统疾病每日死亡人数数据,根据不同年龄、性别及学历将人群分组,采用时间序列的半参数广义相加模型(GAM),定量评价大气PM_(2.5)对居民循环系统疾病死亡人数的影响.单污染物模型和多污染物模型结果表明,PM_(2.5)为影响循环系统疾病每日死亡人数的主要大气污染物.北京市空气中PM_(2.5)的浓度每增加10μg/m^3,循环系统疾病总死亡人数增加0.50%(95%CI:0.36,0.63).不同人群的易感程度不同,各人群死亡人数的增加范围为0.23~0.71%,女性、60~74岁人群、文盲人群的健康风险相对较高.在文盲人群中,老年(60+)女性占比为66.2%,为了分离社会属性人群分类中可能存在的自然属性因素干扰,本文去除其中老年、女性这两个混杂因素的影响,文盲人群健康风险仍然大于较高学历的人群.年龄和性别因素叠加在学历因素上,可能加大低学历人群的健康风险,对于这部分叠加了自然因素和社会因素双重敏感性的人群应给与重点关注. 展开更多
关键词 不同人群 细颗粒物 心血管疾病 时间序列 效应修饰作用
下载PDF
多样化团队群体断裂带研究综述 被引量:14
9
作者 范合君 杜博 《经济管理》 CSSCI 北大核心 2015年第7期182-190,共9页
群体断裂带是基于多样化团队中组织成员的若干特征而形成的,将团队划分为若干相对同质子群的潜在分割线。它不同于传统异质性研究中同一时间关注成员单一特征,而是同一时间考察多样化团队成员的多个特征及其动态聚合,进而演变为"... 群体断裂带是基于多样化团队中组织成员的若干特征而形成的,将团队划分为若干相对同质子群的潜在分割线。它不同于传统异质性研究中同一时间关注成员单一特征,而是同一时间考察多样化团队成员的多个特征及其动态聚合,进而演变为"群体断裂带",为组织多样化及其行为研究提供了一个全新的视角。因此,这一概念的提出,立刻激发了学界的研究热情。通过多样化团队中群体断裂带的现实表现,聚焦于断裂带理论的内涵、测度以及作用机理,梳理已有研究,为将行为研究引入到公司治理的研究核心提供理论借鉴。 展开更多
关键词 多样化团队 异质性 群体断裂带
原文传递
与正规性相关的各种子群之间的关系 被引量:5
10
作者 张勤海 王丽芳 《数学研究》 CSCD 2003年第4期412-417,共6页
本文讨论了正规子群,拟正规子群,s-拟正规子群,半正规子群, c-正规子群,次正规子群,共轭置换子群,半置换子群。s-半置换子群这九种子群之间的关系.
关键词 子群 子群之间的关系
下载PDF
Storage and Spatial Variation of Phosphorus in Paddy Soils of China 被引量:12
11
作者 LIN Jin-Shi SHI Xue-Zheng +4 位作者 LU Xi-Xi YU Dong-Sheng WANG Hong-Jie ZHAO Yong-Cun SUN Wei-Xia 《Pedosphere》 SCIE CAS CSCD 2009年第6期790-798,共9页
Due to the growing concern about the agricultural phosphorus (P) losses pollution, an in-depth understanding of P in paddy soils of China would be helpful in providing a national perspective of the environmental impac... Due to the growing concern about the agricultural phosphorus (P) losses pollution, an in-depth understanding of P in paddy soils of China would be helpful in providing a national perspective of the environmental impact of P cycling and fertility on China's farms. In this study, we evaluated the P storage and the P density of paddy soils in China, characterized the spatial variations of P among the subgroups of paddy soils and soil regions in China, and evaluated the P data using GIS-based analysis, which included a newly compiled 1:1 000 000 digital soil map of China, and using 1 490 soil profiles. The available and total P densities of paddy soils were 6.7 and 698.5 g m -3 , respectively. Overall in China, the total P storage within 1 m of paddy soils was estimated to be 330.2 Tg. The P density of paddy soils varied substantially with subgroups due to the different soil water regimes such as groundwater table and soil drainage. The P availability in paddy soils, especially in surface layer, was higher in high temperature and precipitation areas. Further research is needed to examine more anthropogenic impact factors, such as increasing use of chemical fertilizer. 展开更多
关键词 paddy soil database paddy soil subgroups phosphorus density phosphorus pool
下载PDF
Molecular Detection of FGFR2 Rearrangements in Resected Intrahepatic Cholangiocarcinomas:FISH Could Be An Ideal Method in Patients with Histological Small Duct Subtype 被引量:6
12
作者 Yining Zou Kun Zhu +6 位作者 Yanrui Pang Jing Han Xin Zhang Zhengzeng Jiang Yufeng Huang Wenyi Gu Yuan Ji 《Journal of Clinical and Translational Hepatology》 SCIE 2023年第6期1355-1367,共13页
Background and Aims:Intrahepatic cholangiocarcinoma(ICC)is a subtype of primary liver cancer for which effective therapeutic agents are lacking.Fibroblast growth factor receptor 2(FGFR2)has become a promising therapeu... Background and Aims:Intrahepatic cholangiocarcinoma(ICC)is a subtype of primary liver cancer for which effective therapeutic agents are lacking.Fibroblast growth factor receptor 2(FGFR2)has become a promising therapeutic target in ICC;however,its incidence and optimum testing method have not been fully assessed.This study investigated the rearrangement of FGFR2 in intrahepatic cholangiocarcinoma using multiple molecular detection methods.Methods:The samples and clinical data of 167 patients who underwent surgical resection of intrahepatic cholangiocarcinoma in Zhongshan hospital,Fudan university were collected.The presence of FGFR2 gene rearrangement was confirmed using fluorescence in situ hybridization(FISH)and targeted next-generation sequencing(NGS).FGFR2 protein expression was determined using immunohistochemistry(IHC).The concordance between the methods was statistically compared.PD-L1 expression was also assessed in this cohort.The clinicopathological characteristics and genomic profile related to FGFR2 rearrangements were also analyzed to assist candidatescreening for targeted therapies.Results:FGFR2 rearrangement was detected in 21 of the 167 ICC cases(12.5%)using FISH.NGS analysis revealed that FGFR2 rearrangement was present in 16 of the 20 FISH-positive cases,which was consistent with the FISH results(kappa value=0.696,p<0.01).IHC showed that 80 of the 167 cases(48%)were positive for FGFR2 expression,which was discordant with both FISH and NGS results.By comparison,FGFR2-positivity tended to correlate with unique clinicopathological subgroups,featuring early clinical stage,histologically small duct subtype,and reduced mucus production(P<0.05),with improved overall survival(p<0.05).FGFR2-positivity was not associated with PD-L1 expression in ICCs.In genome research,we identified eight partner genes fused with FGFR2,among which FGFR2-BICC1 was the most common fusion type.BAP1,CDKN2A,and CDKN2B were the most common concomitant genetic alterations of FGFR2,whereas KRAS and IDH1 mutations were mutually exc 展开更多
关键词 Intrahepatic cholangiocarcinoma Fibroblast growth factor receptor 2(FGFR2) Fluorescence in situ hybridization(FISH) Clinicopathological subgroups Prognosis
原文传递
X-s-Permutable Subgroups 被引量:5
13
作者 SHI Lei GUO Wen Bin YI Xiao Lan 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2008年第2期257-265,共9页
Let X be a nonempty subset of a group G. A subgroup H of G is said to be X-spermutable in G if, for every Sylow subgroup T of G, there exists an element x E X such that HT^x= T^xH. In this paper, we obtain some result... Let X be a nonempty subset of a group G. A subgroup H of G is said to be X-spermutable in G if, for every Sylow subgroup T of G, there exists an element x E X such that HT^x= T^xH. In this paper, we obtain some results about the X-s-permutable subgroups and use them to determine the structure of some finite groups. 展开更多
关键词 finite groups formations X-s-permutable subgroups Sylow subgroups maximalsubgroups
下载PDF
New characterizations of finite supersoluble groups 被引量:7
14
作者 Alexander N SKIBA 《Science China Mathematics》 SCIE 2008年第5期827-841,共15页
Let A be a subgroup of a group G and X a nonempty subset of G. A is called an X-semipermutable subgroup of G if A has a supplement T in G such that for every subgroup T 1 of T there exists an element x ∈ X such that ... Let A be a subgroup of a group G and X a nonempty subset of G. A is called an X-semipermutable subgroup of G if A has a supplement T in G such that for every subgroup T 1 of T there exists an element x ∈ X such that AT 1 x = T 1 x A. On the basis of this concept we obtain some new characterizations of finite supersoluble groups. 展开更多
关键词 finite groups SUPPLEMENT 2-maximal subgroups X-semipermutable supersoluble groups 20D10
原文传递
Finite p-Groups Whose Abelian Subgroups Have a Trivial Intersection 被引量:4
15
作者 Shi Rong LI Xiu Yun GUO 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2007年第4期731-734,共4页
A subgroup H of a finite group G is called a TI-subgroup if H ∩ H^x = 1 or H for all x ∈ G. In this paper, a complete classification for finite p-groups, in which all abelian subgroups are TI-subgroups, is given.
关键词 P-GROUPS Abelian subgroups TI-subgroups
原文传递
中国水稻条纹病毒两个亚种群代表性分离物全基因组核苷酸序列分析 被引量:5
16
作者 魏太云 林含新 +2 位作者 吴祖建 林奇英 谢联辉 《中国农业科学》 CAS CSCD 北大核心 2004年第6期846-850,共5页
首次测定了中国水稻条纹病毒(RSV)常年流行区云南楚雄 (CX)分离物及病害暴发区江苏洪泽 (HZ)分离物全基因组核苷酸序列,其中CX 分离物全长为17 093 nts,HZ分离物全长为 17 150 nts。与已报道的日本T分离物全长序列(17 145 nts)相比... 首次测定了中国水稻条纹病毒(RSV)常年流行区云南楚雄 (CX)分离物及病害暴发区江苏洪泽 (HZ)分离物全基因组核苷酸序列,其中CX 分离物全长为17 093 nts,HZ分离物全长为 17 150 nts。与已报道的日本T分离物全长序列(17 145 nts)相比较,CX分离物变异较大。3个分离物基因组结构组成一致,5′端和3′末端非编码区最为保守;7个编码区保守性次之;变异主要发生在IR上。同源性分析表明,HZ分离物与日本T分离物的亲缘关系较中国2个分离物间的亲缘关系更为接近,这表明HZ和CX分离物基本上能够代表病毒自然种群中存在的2个差异较为明显的亚种群。 展开更多
关键词 中国 水稻条纹病毒 亚种群 基因组 序列分析 条纹叶枯病
下载PDF
Finite p-Groups in Which the Number of Subgroups of Possible Order Is Less Than or Equal to p^3 被引量:8
17
作者 Haipeng QU Ying SUN Qinhai ZHANG 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2010年第4期497-506,共10页
In this paper, groups of order p^n in which the number of subgroups of possible order is less than or equal to p3 ale classified. It turns out that if p 〉 2, n≥ 5, then the classification of groups of order p^n in w... In this paper, groups of order p^n in which the number of subgroups of possible order is less than or equal to p3 ale classified. It turns out that if p 〉 2, n≥ 5, then the classification of groups of order p^n in which the number of subgroups of possible order is less than or equal to p3 and the classification of groups of order p^n with a cyclic subgroup of index p2 are the same. 展开更多
关键词 Inner abelian p-groups Metacyclic p-groups Groups of order p^n with a cyclic subgroup of index p^2 The number of subgroups
原文传递
Immunomodulatory effects of Caulerpa racemosa var peltata polysaccharide and its selenizing product on T lymphocytes and NK cells in mice 被引量:6
18
作者 SHEN WeiZai WANG Hui +1 位作者 GUO GuoQing TUO JingJing 《Science China(Life Sciences)》 SCIE CAS 2008年第9期795-801,共7页
A polysaccharide, CrvpPS, was isolated from Caulerpa racemosa var peltata. It was reacted with nano-selenium in distilled water containing ascorbic acid (Vit C) to form a stable CrvpPS-nano-Se complex. The immunomodul... A polysaccharide, CrvpPS, was isolated from Caulerpa racemosa var peltata. It was reacted with nano-selenium in distilled water containing ascorbic acid (Vit C) to form a stable CrvpPS-nano-Se complex. The immunomodulatory effects of CrvpPS and CrvpPS-nano-Se on T lymphocytes subgroups and NK cells in mice were investigated. After intragastric administration for 10 days separately, both CrvpPS and CrvpPS-nano-Se showed significant stimulatory functions to thymus gland of mice. Moreover, the CrvpPS-nano-Se induced the percentage of CD3+, CD3+CD4+, NK cells and the CD4+/CD8+ value to increase significantly (P<0.05) when analyzed by flow cytometry, which is better than the CrvpPS, sucrose-nano-Se, and even the positive drug levamisole. 展开更多
关键词 Caulerpa racemosa var peltata polysaccharides(CrvpPS) nano-Se T lymphocyte subgroups natural killer cells IMMUNOMODULATION flow cytometric analysis
原文传递
The influence of s-conditionally permutable subgroups on finite groups 被引量:5
19
作者 LI BaoJun ZHANG ZhiRang 《Science China Mathematics》 SCIE 2009年第2期301-310,共10页
A subgroup H of a group G is called s-conditionally permutable in G if for every Sylow subgroup T of G there exists an element x ∈ G such that HTx = TxH. Using the concept of s-conditionally permutable subgroups, som... A subgroup H of a group G is called s-conditionally permutable in G if for every Sylow subgroup T of G there exists an element x ∈ G such that HTx = TxH. Using the concept of s-conditionally permutable subgroups, some new characterizations of finite groups are obtained and several interesting results are generalized. 展开更多
关键词 s-conditionally permutable subgroups supersoluble groups finite groups saturated formations 20D10
原文传递
ON F-z-SUPPLEMENTED SUBGROUPS OF FINITE GROUPS 被引量:5
20
作者 郭文彬 唐娜 李保军 《Acta Mathematica Scientia》 SCIE CSCD 2011年第1期22-28,共7页
A subgroup H of a group G is called F-z-supplemented in G if there exists a subgroup K of G, such that G = HK and H∩K≤ Z∞F(G), where Z∞F(G) is the F-hypercenter of G. We obtain some results about the F-z-suppl... A subgroup H of a group G is called F-z-supplemented in G if there exists a subgroup K of G, such that G = HK and H∩K≤ Z∞F(G), where Z∞F(G) is the F-hypercenter of G. We obtain some results about the F-z-supplemented subgroups and use them to determine the structure of some groups. 展开更多
关键词 Finite groups local formations F-z-supplemented subgroups supersoluble groups p-nilpotent groups
下载PDF
上一页 1 2 202 下一页 到第
使用帮助 返回顶部