期刊文献+
共找到62,477篇文章
< 1 2 250 >
每页显示 20 50 100
阶级分层:对当代中国社会分层的另一种解读——基于学理层面思考的中国阶级分层 被引量:34
1
作者 仇立平 《上海大学学报(社会科学版)》 CSSCI 北大核心 2007年第2期58-64,共7页
卡尔.马克思的社会阶级理论仍然适合分析当代中国的社会分层。按照马克斯.韦伯的关于阶级和阶层是一个历史过程的观点,中国开始出现阶级现象;并尝试运用稀缺性生产要素占有关系解读当下的中国阶级状况及其相互关系;认为阶级分化或冲突... 卡尔.马克思的社会阶级理论仍然适合分析当代中国的社会分层。按照马克斯.韦伯的关于阶级和阶层是一个历史过程的观点,中国开始出现阶级现象;并尝试运用稀缺性生产要素占有关系解读当下的中国阶级状况及其相互关系;认为阶级分化或冲突并不必然会导致阶级对抗,阶级合作是现代社会的一个理性选择。 展开更多
关键词 社会分层 阶层 阶级 稀缺性生产要素
下载PDF
Moran sets and Moran classes 被引量:21
2
作者 WEN ZhiyingDepartment of Mathematics, Tsinghua University, Beijing 100084, China 《Chinese Science Bulletin》 SCIE EI CAS 2001年第22期1849-1856,共8页
The purpose of this survey is to present Moran sets and Moran classes which generalize the classical self-similar sets from the following points: (i) The placements of the basic sets at each step of the constructions ... The purpose of this survey is to present Moran sets and Moran classes which generalize the classical self-similar sets from the following points: (i) The placements of the basic sets at each step of the constructions can be arbitrary; (ii) the contraction ratios may be different at each step; and (iii) the lower limit of the contraction ratios permits zero. In this discussion we will present geometrical properties and results of dimensions of these sets and classes, and discuss conformal Moran sets and random Moran sets as well. 展开更多
关键词 MORAN SET MORAN classes dimension.
原文传递
基于GIS的华北-辽南土地潜力区土地适宜性评价 被引量:18
3
作者 侯西勇 岳燕珍 +1 位作者 于贵瑞 何洪林 《资源科学》 CSSCI CSCD 北大核心 2007年第4期201-207,共7页
以华北-辽南土地潜力区为案例区,研究了GIS技术支持下基于多要素空间数据进行土地适宜性评价的方法与技术,评价对象包括土地限制因子、土地限制型、土地质量等和土地适宜类。根据研究区的自然地理和土地资源系统特征,选取气候、地形、... 以华北-辽南土地潜力区为案例区,研究了GIS技术支持下基于多要素空间数据进行土地适宜性评价的方法与技术,评价对象包括土地限制因子、土地限制型、土地质量等和土地适宜类。根据研究区的自然地理和土地资源系统特征,选取气候、地形、灌排水、土壤和植被等五大类10个指标为评价因子;应用基于栅格数据模型的空间分析技术在1km2尺度建立评价因子基础数据库,并将评价原则用地图代数语言加以表达,形成了“要素数据”、“原则标准”与“分析技术”相结合的、逐级递进的评价技术流程。案例区实证研究表明:评价方法与技术切实可行,高质量的基础数据、合理的评价方法和有效的分析技术共同保证了评价过程的准确与高效;案例区的土地限制因子以土壤质地、水文与排水条件、坡度和灌溉条件为主,而土地适宜类则以宜农类、宜林牧类和宜农林牧类为主。 展开更多
关键词 适宜性 限制因子 限制型 质量等 适宜类 华北-辽南土地潜力区
下载PDF
ON CHROMATIC POLYNOMIALS OF TWO CLASSES OF GRAPHS 被引量:19
4
作者 刘儒英 《Chinese Science Bulletin》 SCIE EI CAS 1987年第16期1147-1148,共2页
Up to the present, there are few classes of graphs of which chromatic polynomials can be computed with formulas. For most graphs, computing their chromatic
关键词 CHROMATIC classes SPANNING FORMULAS COMPLEMENT LETTER 二土 刃刀 石飞 length
原文传递
浅谈和谐班级的构建 被引量:12
5
作者 赵文秀 张丽娟 《昆明大学学报》 2007年第2期110-112,116,共4页
和谐的校园由和谐的班集体构成,和谐的班集体靠学校教师来构建,因此构建和谐班级是班主任义不容辞的责任。班主任应从建立和谐师生关系、生生关系和学习环境等方面去构建和谐班级。
关键词 构建 和谐 班级
下载PDF
智慧体育环境下高校体育课内外一体化教学模式优化研究 被引量:6
6
作者 徐芳 《吉林农业科技学院学报》 2023年第6期74-76,109,共4页
依托智慧体育平台支撑,通过资源共享,信息交互构建智慧学习型教学生态系统,有助于体育课堂与课外体育的精准对接互动和协同管理。运用文献资料法、逻辑分析法,针对当前高校体育课内、课外教学现状,从教学决策数据化、教学手段智慧化、... 依托智慧体育平台支撑,通过资源共享,信息交互构建智慧学习型教学生态系统,有助于体育课堂与课外体育的精准对接互动和协同管理。运用文献资料法、逻辑分析法,针对当前高校体育课内、课外教学现状,从教学决策数据化、教学手段智慧化、资源推送智能化、运动场地智能化、测试工作高效化、实时监测安全化入手,提出了构建高校体育课内外一体化教学模式的优化路径,以期助力立德树人育人目标的顺利实现。 展开更多
关键词 智慧体育 高校体育 课内外 一体化 教学模式
下载PDF
Heterotic Classes and Utilization Patterns in Chinese Foxtail Millet [<i>Setaria italica</i>(L.) P. Beauv] 被引量:7
7
作者 Zhengli Liu Guihua Bai +3 位作者 Dadong Zhang Chengsong Zhu Xiaoli Ren Suying Li 《Agricultural Sciences》 2014年第14期1392-1406,共15页
Utilization of heterosis to develop hybrid cultivars can significantly increase yield of most crops including foxtail millet. However, previous foxtail millet hybrid cultivars have been largely developed from crosses ... Utilization of heterosis to develop hybrid cultivars can significantly increase yield of most crops including foxtail millet. However, previous foxtail millet hybrid cultivars have been largely developed from crosses between sterile lines and conventional varieties or between sterile lines and varieties that are geographically distent from the sterile lines. The research on classification of heterotic classes and determinetaion of heterotic patterns has not been reported, which results in uncertainty in selection of parents for crosses and delays progress in utilization of high yielding hybrids in large-scale commercial production. In this study, a core collection of 128 accessions from China was grouped into six classes using combined analyses of population structure, pedigree, and clustering. The classification was conducted based mainly on molecular clustering of genotypic data, also considered the population structure and mathematical clustering using phenotypic data, and was finally validated through pedigree analysis. According to the transgressive and superstandard heterosis for grain yield, plant height, panicle length, panicle diameter, single panicle weight, grain weight per panicle, and 1000-grain weight collected from an incomplete-diallel-cross experiment, we identified six superior heterosis patterns (C2/C1, C2/C4, C2/C5, C2/C6, C1/C5 and C4/C5) and four inferior heterosis patterns (C1/C3, C1/C4, C1/C6 and C4/C6), and explored their potential applications in millet hybrid breeding. This study laid a foundation for effective use of foxtail millet heterosis in improving millet hybrid yield. 展开更多
关键词 Foxtail MILLET Heterotic classes Heterotic Pattern Molecular Clustering POPULATION Structure
下载PDF
Impact of Non-Compliance of Exposure Classes in Reinforced Concrete Structures
8
作者 Serigne Touba Thiam Mouhamed Lamine Chérif Aidara Alinté Diatta 《Open Journal of Civil Engineering》 CAS 2023年第1期25-34,共10页
From the National Agency for the Organization and Construction of Infrastructures (ANOCI) program to the Emerging Senegal Plan (PSE), construction in Senegal has improved considerably. However, deficiencies remain in ... From the National Agency for the Organization and Construction of Infrastructures (ANOCI) program to the Emerging Senegal Plan (PSE), construction in Senegal has improved considerably. However, deficiencies remain in the specification of materials used mainly in hydraulic concrete. They are generally related to the specification of aggregates for alkali reactivity and the choice of exposure classes specified in NF EN 206-1. The purpose of this article is to study the incidence of non-compliance with exposure classes in reinforced concrete structures. To carry out this study, surveys were carried out at several sites (districts) in Dakar (Cité Avion, Touba Ouakam, Cité Asecna, Cité Batrain, Cité Comico, Cité Assemblée and Terme Sud) in order to collect information on the formulation and implementation methods used. The comparison of the various readings carried out made it possible to deduce conclusions and to give recommendations when using standard NF EN 206-1. 展开更多
关键词 Common Exposure classes Specific Exposure classes Concrete Alkali-Reaction
下载PDF
基于依赖结构分析的类重要性度量方法 被引量:8
9
作者 周毓明 徐宝文 《东南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2008年第3期380-384,共5页
为支持自动识别系统中重要的类,提出了一种基于软件依赖结构分析的类重要性度量方法.该方法首先用一个图模型表达类之间的3种依赖关系,包括类-类继承依赖、类-属性交互依赖和类-方法交互依赖,然后用PageRank,HITS和Betweenness Central... 为支持自动识别系统中重要的类,提出了一种基于软件依赖结构分析的类重要性度量方法.该方法首先用一个图模型表达类之间的3种依赖关系,包括类-类继承依赖、类-属性交互依赖和类-方法交互依赖,然后用PageRank,HITS和Betweenness Centrality算法通过对依赖关系结构的全局分析来度量类的重要性.该方法仅使用在软件开发的分析和设计阶段可以得到的信息,因而可用来在软件开发的早期识别系统中重要的类.实验结果表明,在识别重要的类时,该方法产生与简单方法不同的结果. 展开更多
关键词 依赖结构 重要性 度量 面向对象
下载PDF
氮肥种类对蔬菜产量和品质影响的研究 被引量:3
10
作者 李天贵 周兆德 黄启为 《湖南农学院学报》 CSCD 1991年第1期17-22,共6页
尿素、碳铵和氯铵对蔬菜产量和品质的影响的田间试验结果表明,大白菜在等氮量情况下,对尿素,碳铵和氯铵的肥效无显著差异,盆栽试验结果也表明,尿素与碳铵肥效相当,唯氯铵肥效因蔬菜种类而异,氯铵有明显降低蔬菜硝酸盐含量的效果,氯铵与... 尿素、碳铵和氯铵对蔬菜产量和品质的影响的田间试验结果表明,大白菜在等氮量情况下,对尿素,碳铵和氯铵的肥效无显著差异,盆栽试验结果也表明,尿素与碳铵肥效相当,唯氯铵肥效因蔬菜种类而异,氯铵有明显降低蔬菜硝酸盐含量的效果,氯铵与尿素相比,约降低硝酸盐50%,在中等氮素水平下,尿素、碳铵和氯铵处理,蔬菜硝酸盐平均含量分别为659,633和440 ppm,除氯铵处理在允许范围内外,尿素和碳铵处理均超过标准。 展开更多
关键词 绿叶蔬菜 氮肥 施肥 产量 硝酸盐
全文增补中
当学生不再自觉——关于课堂手机集中管理的教育案例分析 被引量:8
11
作者 英起志 《科教文汇》 2013年第36期171-171,173,共2页
课堂手机管理是学校教育和学生管理的一个难点问题,为了保证课堂纪律和效果,每个学校都有各自的手机管理规定,内容不尽相同,成效也各不相同。本文以手机集中管理下的职业学院课堂为背景,对一起成功的教育案例进行了分析,总结了教师在管... 课堂手机管理是学校教育和学生管理的一个难点问题,为了保证课堂纪律和效果,每个学校都有各自的手机管理规定,内容不尽相同,成效也各不相同。本文以手机集中管理下的职业学院课堂为背景,对一起成功的教育案例进行了分析,总结了教师在管理中应当发挥的作用以及教育学生的正确方式方法。 展开更多
关键词 学生 手机 管理 课堂 习惯养成
下载PDF
智能社会的体制诉求和人的本质的新进化 被引量:8
12
作者 邬焜 冯洁 +1 位作者 袁燕 马红燕 《自然辩证法研究》 CSSCI 北大核心 2019年第1期123-128,共6页
随着社会发展的智能化程度的提高,人类的必要劳动时间将会大幅度缩短,由此导致的失业大军的快速增长将会是社会进步的集中体现。智能化社会的发展将会导致新的阶层分化。新的阶层分化必将会带来新的社会问题和全新社会协调体制的诉求。... 随着社会发展的智能化程度的提高,人类的必要劳动时间将会大幅度缩短,由此导致的失业大军的快速增长将会是社会进步的集中体现。智能化社会的发展将会导致新的阶层分化。新的阶层分化必将会带来新的社会问题和全新社会协调体制的诉求。适合于未来智能化社会的全新社会体制一定是社会财富高度共享的社会。随着人类社会发展的智能化程度的不断提高,人也在不断改变、创造着自身的本质,也不断地从对某种单一性旧的本质的束缚中得到解放,使自身本质的更为丰富、多样的方面创生出来并得以展现。 展开更多
关键词 智能化 失业 阶层 社会体制 人的本质
原文传递
IFC implementation in lifecycle costing 被引量:7
13
作者 Charlie Fu Ghassan Aouad +2 位作者 Amanda Marshall Ponting Angela Lee Song Wu 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2004年第4期437-441,共5页
Life Cycle Costing (LCC) is always a major concern in the Architecture, Engineering and Construction (AEC) industry. This paper presents the implementation of Building Information Modeling (BIM) technology in the deve... Life Cycle Costing (LCC) is always a major concern in the Architecture, Engineering and Construction (AEC) industry. This paper presents the implementation of Building Information Modeling (BIM) technology in the development of a lifecycle cost-estimating tool. The IFC (Industry Foundation Classes) model as an interoperable building information model has been adopted as the central data repository to deliver the integrated information of building designs from CAD design systems into the lifecycle-costing database. In this paper, the conceptions and relevant factors, which could affect the LCC estimation, have been introduced. The problems of current LCC applications have been identified as the lack of LCC data and the complexity of LCC exercises. The software application of IFC models and relevant auxiliary are depicted as a solution of the problem identified. The lifecycle costing tool is a part of the nD Modeling tool and as such is based on its integrated interface prototype toolkit and is able to holistically present an IFC model into a 3D virtual reality view, a tree-view and a list of element properties. The functions and some technical points are also detailed in the paper. Through the research, it demonstrates the potential and possibility of implementing BIM methods and techniques, particularly IFCs to enhance the computer applications in the processes of building construction and facility management. 展开更多
关键词 AEC industry life cycle costing building information modeling industry foundation classes
下载PDF
Classification and Net Primary Productivity of the Southern China's Grasslands Ecosystem Based on Improved Comprehensive and Sequential Classification System(CSCS) Approach 被引量:6
14
作者 SUN Zheng-guo SUN Cheng-ming +2 位作者 ZHOU Wei JU Wei-min LI Jian-long 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2014年第4期893-903,共11页
This research classified vegetation types and evaluated net primary productivity (NPP) of southern China's grasslands based on the improved comprehensive and sequential classification system (CSCS), and proposed ... This research classified vegetation types and evaluated net primary productivity (NPP) of southern China's grasslands based on the improved comprehensive and sequential classification system (CSCS), and proposed 5 thermal grades and 6 humidity grades. Four classes of grasslands vegetation were recognized by improved CSCS, namely, tundra grassland class, typical grassland class, mixed grassland class and alpine grassland class. At the type level, 14 types of vegetations (9 grasslands and 5 forests) were classified. The NPP had a trend to decrease from east to west and south to north, and the annual mean NPP was estimated to be 656.3 g C m-2 yr-1. The NPP value of alpine grassland class was relatively high, generally more than 1200 g C m2 yr-1. The NPP value of mixed grassland class was in a range from 1 000 to 1200 g C m-2 yr-1. Tundra grassland class was located in southeastern Tibet with high elevation, and its NPP value was the lowest (〈600 g C m'2yrl). The typical grassland class distributed in most of the area, and its NPP value was generally from 600 to 1000 g C m-2 yr-1. The total NPP value in the study area was 68.46 Tg C. The NPP value of typical grassland class was the highest (48.44 Tg C), and mixed grassland class was the second (16.54 Tg C), followed by alpine grassland class (3.22 Tg C), with tundra grassland class being the lowest (0.25 Tg C). For all the grasslands types, the total NPP of forest meadow was the highest (34.81 Tg C), followed by sparse forest brush (16.54 Tg C), and montane meadow was the lowest (0.01 Tg C). 展开更多
关键词 improved CSCS hydro-thermal pattern southem China grasslands classes and types net primary productivity (NPP)
下载PDF
新课程标准背景下关于高中语文课堂教学的几点思考 被引量:7
15
作者 乔春颖 《学周刊(中旬)》 2016年第4期193-194,共2页
高中语文新课程标准要求:"按‘知识和能力’‘过程和方法’‘情感态度和价值观’三个维度的目标,全面提高学生的语文素养,同时应根据新时期高中语文教育的任务和学生的需求,努力改革课程的内容、结构和实施机制,充分发挥语文课程... 高中语文新课程标准要求:"按‘知识和能力’‘过程和方法’‘情感态度和价值观’三个维度的目标,全面提高学生的语文素养,同时应根据新时期高中语文教育的任务和学生的需求,努力改革课程的内容、结构和实施机制,充分发挥语文课程的育人功能。"在这一背景下,各地的教学改革可谓各出奇招、异彩纷呈。文章主要探究了提高教学效率的三大方面,以供参考。 展开更多
关键词 高中语文 课堂 教学
下载PDF
明代州县区划及其沿革 被引量:3
16
作者 柏桦 《史学月刊》 CSSCI 北大核心 2003年第1期32-40,共9页
明代州县增设改置的原因主要有三种 :一是有历史的遗留 ,二是有自然地理环境的限制 ,三是有当时政治的制约。自然地理环境固然有其优势 ,但它不能把人完全隔绝 ;历史遗留和当时的政治 ,都是人为的因素。州县的增改、疆域的划分 ,无疑是... 明代州县增设改置的原因主要有三种 :一是有历史的遗留 ,二是有自然地理环境的限制 ,三是有当时政治的制约。自然地理环境固然有其优势 ,但它不能把人完全隔绝 ;历史遗留和当时的政治 ,都是人为的因素。州县的增改、疆域的划分 ,无疑是人的因素起主导作用。分析明代 740多个州县增改的原因 ,不但可以看出统治者为加强自身统治而花费的苦心 ,而且也可以看出州县的政治职能。 展开更多
关键词 州县 疆界 改置 行政区划 等级
下载PDF
Infl uence of altitude and tree class on climate-growth relationships in a larch plantation in subtropical China 被引量:3
17
作者 Chunyan Wu Dongsheng Chen +1 位作者 Xiaomei Sun Shougong Zhang 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第6期1869-1880,共12页
Precise quantifi cation of climate-growth relationships can make a major contribution to scientifi c forest management.However,whether diff erences in the response of growth to climate at diff erent altitudes remains ... Precise quantifi cation of climate-growth relationships can make a major contribution to scientifi c forest management.However,whether diff erences in the response of growth to climate at diff erent altitudes remains unclear.To answer this,264 trees of Larix kaempferi from 88 plots,representing diff erent altitudinal ranges(1000-2100 m)and tree classes were sampled and used to develop tree-ring chronologies.Tree-ring growth(TRG)was either positively(dominant)or negatively(intermediate and suppressed)correlated with climate in diff erent tree classes at diff erent altitudes.TRG was strongly correlated with growing season at low altitudes,but was less sensitive to climate at middle altitudes.It was mainly limited by precipitation and was highly sensitive to climate at low altitudes.Climate-growth relationships at high altitudes were opposite compared to those at low altitudes.TRG of dominant trees was more sensitive to climate change compared to intermediate and suppressed trees.Climate factors(annual temperatures;moisture,the number of frost-free days)had diff erent eff ects on tree-ring growth of diff erent tree classes along altitudinal gradients.It was concluded that the increase in summer temperatures decreased water availability,resulting in a signifi cant decline in growth rates after 2005 at lower altitudes.L.kaempferi is suitable for planting in middle altitudes and dominant trees were the best sampling choice for accurately assessing climate-growth relationships. 展开更多
关键词 Tree-ring width index CHRONOLOGY Correlation coeffi cient Additive mixed models Tree classes
下载PDF
昆虫气味结合蛋白研究进展 被引量:7
18
作者 缪森 张龙 王丽红 《云南大学学报(自然科学版)》 CAS CSCD 2003年第S1期161-165,169,共6页
随着昆虫触觉气味结合蛋白的发现,目前,昆虫气味结合蛋白研究已进入细胞分子水平,昆虫学研究者希望从生化及分子水平弄清昆虫气味结合蛋白的生理功能,揭示昆虫气味结合蛋白与昆虫行为的关系.本文就昆虫气味结合蛋白的研究种类、生化特... 随着昆虫触觉气味结合蛋白的发现,目前,昆虫气味结合蛋白研究已进入细胞分子水平,昆虫学研究者希望从生化及分子水平弄清昆虫气味结合蛋白的生理功能,揭示昆虫气味结合蛋白与昆虫行为的关系.本文就昆虫气味结合蛋白的研究种类、生化特性、生理功能、目前存在关于昆虫气味结合蛋白如何执行其功能的假说等进行综述. 展开更多
关键词 气味结合蛋白 种类 生化特性 功能 假说
原文传递
高校班级量化管理探索与实践 被引量:7
19
作者 覃吉春 王静萍 《中国地质教育》 2008年第2期112-114,共3页
班级作为高校学生的基本组织单位,各种教学及管理工作都是通过班级来实现的,加强高校班级管理是顺利完成各种教育教学的重要保障。因此,高校都很重视班级管理工作,并摸索出很多行之有效的管理办法。本文就班级管理的概念、意义、途径等... 班级作为高校学生的基本组织单位,各种教学及管理工作都是通过班级来实现的,加强高校班级管理是顺利完成各种教育教学的重要保障。因此,高校都很重视班级管理工作,并摸索出很多行之有效的管理办法。本文就班级管理的概念、意义、途径等问题进行了探索和实践。 展开更多
关键词 高校 班级 量化管理
下载PDF
Isomorphism classes of hyperelliptic curves of genus 2 over finite fields with characteristic 2 被引量:5
20
作者 DENG Yingpu LIU Mulan 《Science China Mathematics》 SCIE 2006年第2期173-184,共12页
In this paper we study the computation of the number of isomorphism classes of hyperelliptic curves of genus 2 over finite fields Fq with q even. We show the formula of the number of isomorphism classes, that is, for ... In this paper we study the computation of the number of isomorphism classes of hyperelliptic curves of genus 2 over finite fields Fq with q even. We show the formula of the number of isomorphism classes, that is, for q = 2m, if 4 (|) m, then the formula is 2q3 + q2 - q;if 4 | m, then the formula is 2q3 + q2 - q + 8. These results can be used in the classification problems and the hyperelliptic curve cryptosystems. 展开更多
关键词 hyperelliptic CURVES hyperelliptic curve CRYPTOSYSTEMS JACOBIAN GROUPS ISOMORPHISM classes.
原文传递
上一页 1 2 250 下一页 到第
使用帮助 返回顶部