首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1083篇
  免费   40篇
  国内免费   11篇
管理学   68篇
民族学   7篇
人口学   16篇
丛书文集   104篇
理论方法论   36篇
综合类   690篇
社会学   27篇
统计学   186篇
  2023年   8篇
  2022年   12篇
  2021年   11篇
  2020年   16篇
  2019年   25篇
  2018年   17篇
  2017年   17篇
  2016年   34篇
  2015年   36篇
  2014年   117篇
  2013年   105篇
  2012年   61篇
  2011年   60篇
  2010年   52篇
  2009年   33篇
  2008年   44篇
  2007年   56篇
  2006年   53篇
  2005年   47篇
  2004年   50篇
  2003年   48篇
  2002年   38篇
  2001年   50篇
  2000年   37篇
  1999年   16篇
  1998年   11篇
  1997年   10篇
  1996年   10篇
  1995年   12篇
  1994年   9篇
  1993年   8篇
  1992年   11篇
  1991年   6篇
  1990年   2篇
  1989年   7篇
  1988年   1篇
  1987年   2篇
  1985年   2篇
排序方式: 共有1134条查询结果,搜索用时 531 毫秒
31.
The likelihood ratio method is used to construct a confidence interval for a population mean when sampling from a population with certain characteristics found in many applications, such as auditing. Specifically, a sample taken from this type of population usually consists of a very large number of zero values, plus a small number of nonzero values that follow some continuous distribution. In this situation, the traditional confidence interval constructed for the population mean is known to be unreliable. This article derives confidence intervals based on the likelihood-ratio-test approach by assuming (1) a normal distribution (normal algorithm) and (2) an exponential distribution (exponential algorithm). Because the error population distribution is usually unknown, it is important to study the robustness of the proposed procedures. We perform an extensive simulation study to compare the percentage of confidence intervals containing the true population mean using the two proposed algorithms with the percentage obtained from the traditional method based on the central limit theorem. It is shown that the normal algorithm is the most robust procedure against many different distributional error assumptions.  相似文献   
32.
2003年、2004年在曲靖市,2006年在昆明市分别发现了侵华日军绘制的云南地形图,这些地图佐证了日本进攻中国的第二条战线战略,即日军1942年5月占领云南滇西地区后,欲趁势扩大战果,谋图继续进攻滇中、滇东北,再从滇东北攻占重庆、成都,从而形成从西南进攻中国的第二条战线。由于日军兵力不足、太平洋战争失利等诸多原因导致其进攻中国的第二条战线战略破产。  相似文献   
33.
Abstract

This article introduces a parametric robust way of comparing two population means and two population variances. With large samples the comparison of two means, under model misspecification, is lesser a problem, for, the validity of inference is protected by the central limit theorem. However, the assumption of normality is generally required, so that the inference for the ratio of two variances can be carried out by the familiar F statistic. A parametric robust approach that is insensitive to the distributional assumption will be proposed here. More specifically, it will be demonstrated that the normal likelihood function can be adjusted for asymptotically valid inferences for all underlying distributions with finite fourth moments. The normal likelihood function, on the other hand, is itself robust for the comparison of two means so that no adjustment is needed.  相似文献   
34.
《鄂豫边区民运工作史》反映出的中国共产党群众路线的组织形式、工作方法、实现路径等,体现了群众路线的具体性,对当今中国特色的社会主义建设事业有着重要的启迪和借鉴作用。  相似文献   
35.
针对运用断裂力学传统方法进行裂纹尖端的弹塑性应力场分析均为小范围塑性区的假定,不能准确反映塑性区应力情况的问题,利用裂纹线场分析方法,对理想弹塑性材料的有限宽平面板在裂纹面受到一对集中剪力作用时裂纹线附近的应力场及弹塑性边界进行了分析。不采用小范围塑性区的假设,直接通过将裂纹线附近弹塑性边界上弹性应力场与塑性应力场的匹配,获得了裂纹线附近弹塑性应力场的解析解以及弹塑性边界上单位法向量的表达式。用裂纹线分析方法可以准确地反映裂纹附近的弹塑性应力分布,该种方法的应用将成为断裂力学的一个重要发展方向,对石油天然气构造应力分析、材料力学分析具有参考价值。  相似文献   
36.
A project is carried out for instructors in the agricultural extension service in Esfahan. Part of the project is study, conducted to inform the process of competency profile development for the instructors. The study, reported in this contribution, focuses on views of experts about competencies needed by the instructors. The survey is based on the methodology for developing models of HRD, in which 257 key experts participated. A mix of methods was used for collecting data. The most important competencies found in this study are subject matter and business understanding, and presentation skill. The most essential outputs are presentation of instructional materials, feedback to learners and equipping learners with new competencies after the course. In this contribution, competencies and outputs are elaborated. Further research is needed regarding performance improvement as a result of the efforts of the instructors, and the views of other stakeholders on the development of the agri-clusters.  相似文献   
37.
We propose a semiparametric approach for the analysis of case–control genome-wide association study. Parametric components are used to model both the conditional distribution of the case status given the covariates and the distribution of genotype counts, whereas the distribution of the covariates are modelled nonparametrically. This yields a direct and joint modelling of the case status, covariates and genotype counts, and gives a better understanding of the disease mechanism and results in more reliable conclusions. Side information, such as the disease prevalence, can be conveniently incorporated into the model by an empirical likelihood approach and leads to more efficient estimates and a powerful test in the detection of disease-associated SNPs. Profiling is used to eliminate a nuisance nonparametric component, and the resulting profile empirical likelihood estimates are shown to be consistent and asymptotically normal. For the hypothesis test on disease association, we apply the approximate Bayes factor (ABF) which is computationally simple and most desirable in genome-wide association studies where hundreds of thousands to a million genetic markers are tested. We treat the approximate Bayes factor as a hybrid Bayes factor which replaces the full data by the maximum likelihood estimates of the parameters of interest in the full model and derive it under a general setting. The deviation from Hardy–Weinberg Equilibrium (HWE) is also taken into account and the ABF for HWE using cases is shown to provide evidence of association between a disease and a genetic marker. Simulation studies and an application are further provided to illustrate the utility of the proposed methodology.  相似文献   
38.
网络应用的普及给现代社会管理提出了新课题,各地网络问政的实践探索正在尝试作出回答。深入剖析在网络传播时代坚持走群众路线的新要求、新内涵,研究网络问政所产生的公共传播效应、舆论压力效应、民智汇集效应和议程推动效应,探求其内在规律及其实践要求,对于创新社会管理、维护和发展群众权益,可以起到积极、有效的促进作用。  相似文献   
39.
利用多道光学分析仪(OSMA)测量HT-6M托卡马克限制器前Hα线形分布,通过高斯拟合由多普勒展宽和多普勒频移分别得出等离子体离子温度和再循环粒子流速。  相似文献   
40.
对我国公安机关的两种行为——行政行为与刑事司法行为进行了分析、比较。公安机关在实践中由于滥用刑事司法权 ,导致刑事司法行为和行政行为难以界定 ,这给人民法院的司法实践带来困难。针对这种状况 ,提出了界定我国公安机关的行政行为与刑事司法行为的标准 ,并对最高人民法院《关于执行〈行政诉讼法〉若干问题的解释》中对这一问题的规定作出评析  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号