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   8982篇
  免费   437篇
  国内免费   141篇
管理学   484篇
劳动科学   2篇
民族学   71篇
人才学   1篇
人口学   131篇
丛书文集   595篇
理论方法论   288篇
综合类   3683篇
社会学   460篇
统计学   3845篇
  2024年   24篇
  2023年   106篇
  2022年   145篇
  2021年   177篇
  2020年   230篇
  2019年   335篇
  2018年   364篇
  2017年   462篇
  2016年   355篇
  2015年   314篇
  2014年   527篇
  2013年   1275篇
  2012年   656篇
  2011年   502篇
  2010年   418篇
  2009年   423篇
  2008年   420篇
  2007年   488篇
  2006年   387篇
  2005年   359篇
  2004年   311篇
  2003年   260篇
  2002年   211篇
  2001年   194篇
  2000年   144篇
  1999年   93篇
  1998年   84篇
  1997年   55篇
  1996年   38篇
  1995年   40篇
  1994年   34篇
  1993年   25篇
  1992年   26篇
  1991年   13篇
  1990年   11篇
  1989年   7篇
  1988年   11篇
  1987年   9篇
  1986年   7篇
  1985年   7篇
  1984年   6篇
  1983年   6篇
  1980年   1篇
排序方式: 共有9560条查询结果,搜索用时 406 毫秒
21.
地方治理意味着地方政府从中央一体化的垂直结构下抽身,确立自身的独立地位与利益;同时,它也表征着民间社会力量的成长并逐步参与地方公共事务,成为地方治理中重要的参与性力量。在此意义上,善治理论提供了具有借鉴意义的理论框架和分析范式。但是,处于转型期的中国社会,在用善治理论观照中国地方治理时,其前提和基础条件的具备与否是受到质疑的,从而,这一分析框架的适用性也是有限的。  相似文献   
22.
Olive Oil Consumption in Greece: A Microeconometric Analysis   总被引:2,自引:1,他引:1  
In this paper, the factors affecting at-home demand for three types of oils and fats in Greece, with emphasis on olive oil, are investigated using the linear approximation of the Almost Ideal Demand System and family budget survey data. To overcome the econometric problem created with the existence of zero expenditure, a generalization of the two-stage Heckman procedure is employed. In order to investigate the role of self-consumption, two different samples were used. The first includes all households; the second excludes those that acquire olive oil only from own production. According to the results, there are important differences in the first stage of the decision process between the two samples. Unlike the first stage, the second stage of the decision process found no important differences between the results for the two samples.  相似文献   
23.
The last observation carried forward (LOCF) approach is commonly utilized to handle missing values in the primary analysis of clinical trials. However, recent evidence suggests that likelihood‐based analyses developed under the missing at random (MAR) framework are sensible alternatives. The objective of this study was to assess the Type I error rates from a likelihood‐based MAR approach – mixed‐model repeated measures (MMRM) – compared with LOCF when estimating treatment contrasts for mean change from baseline to endpoint (Δ). Data emulating neuropsychiatric clinical trials were simulated in a 4 × 4 factorial arrangement of scenarios, using four patterns of mean changes over time and four strategies for deleting data to generate subject dropout via an MAR mechanism. In data with no dropout, estimates of Δ and SEΔ from MMRM and LOCF were identical. In data with dropout, the Type I error rates (averaged across all scenarios) for MMRM and LOCF were 5.49% and 16.76%, respectively. In 11 of the 16 scenarios, the Type I error rate from MMRM was at least 1.00% closer to the expected rate of 5.00% than the corresponding rate from LOCF. In no scenario did LOCF yield a Type I error rate that was at least 1.00% closer to the expected rate than the corresponding rate from MMRM. The average estimate of SEΔ from MMRM was greater in data with dropout than in complete data, whereas the average estimate of SEΔ from LOCF was smaller in data with dropout than in complete data, suggesting that standard errors from MMRM better reflected the uncertainty in the data. The results from this investigation support those from previous studies, which found that MMRM provided reasonable control of Type I error even in the presence of MNAR missingness. No universally best approach to analysis of longitudinal data exists. However, likelihood‐based MAR approaches have been shown to perform well in a variety of situations and are a sensible alternative to the LOCF approach. MNAR methods can be used within a sensitivity analysis framework to test the potential presence and impact of MNAR data, thereby assessing robustness of results from an MAR method. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
24.
A test of congruence among distance matrices is described. It tests the hypothesis that several matrices, containing different types of variables about the same objects, are congruent with one another, so they can be used jointly in statistical analysis. Raw data tables are turned into similarity or distance matrices prior to testing; they can then be compared to data that naturally come in the form of distance matrices. The proposed test can be seen as a generalization of the Mantel test of matrix correspondence to any number of distance matrices. This paper shows that the new test has the correct rate of Type I error and good power. Power increases as the number of objects and the number of congruent data matrices increase; power is higher when the total number of matrices in the study is smaller. To illustrate the method, the proposed test is used to test the hypothesis that matrices representing different types of organoleptic variables (colour, nose, body, palate and finish) in single‐malt Scotch whiskies are congruent.  相似文献   
25.
Maximum likelihood estimation and goodness-of-fit techniques are used within a competing risks framework to obtain maximum likelihood estimates of hazard, density, and survivor functions for randomly right-censored variables. Goodness-of- fit techniques are used to fit distributions to the crude lifetimes, which are used to obtain an estimate of the hazard function, which, in turn, is used to construct the survivor and density functions of the net lifetime of the variable of interest. If only one of the crude lifetimes can be adequately characterized by a parametric model, then semi-parametric estimates may be obtained using a maximum likelihood estimate of one crude lifetime and the empirical distribution function of the other. Simulation studies show that the survivor function estimates from crude lifetimes compare favourably with those given by the product-limit estimator when crude lifetimes are chosen correctly. Other advantages are discussed.  相似文献   
26.
Demonstrated equivalence between a categorical regression model based on case‐control data and an I‐sample semiparametric selection bias model leads to a new goodness‐of‐fit test. The proposed test statistic is an extension of an existing Kolmogorov–Smirnov‐type statistic and is the weighted average of the absolute differences between two estimated distribution functions in each response category. The paper establishes an optimal property for the maximum semiparametric likelihood estimator of the parameters in the I‐sample semiparametric selection bias model. It also presents a bootstrap procedure, some simulation results and an analysis of two real datasets.  相似文献   
27.
统计执法的博弈分析   总被引:1,自引:0,他引:1  
针对目前中国统计数据失真相当严重并引起社会各界普遍关注的现象,运用博弈论作为分析工具,引入重复博弈研究了统计执法中数据报方与查方的利益冲突关系,从统计执法的角度揭示了统计数据失真的主要原因,并提出了相应的五项对策。  相似文献   
28.
Abstract.  We correct two proofs concerning Markov properties for graphs representing marginal independence relations.  相似文献   
29.
基于RSA的电子商务信息加密技术研究   总被引:1,自引:0,他引:1  
21世纪是网络信息时代,电子商务的迅猛发展和普及打破了人们传统的经营和消费理念,网上消费已成为一种新的消费形式,但随之而来的便是电子商务赖以生存和发展的安全问题。文章主要通过对电子商务安全隐患的分析,论证了数据加密技术在电子商务安全中的作用,重点探讨了RSA公钥加密算法,并通过实例对其加密原理、计算复杂性等安全性问题作了详尽的分析和阐述。  相似文献   
30.
《辛丑条约》签订后,清政府开始在政治上进行变革,推行“新政”和预备立宪。在此过程中,自晚清以降出现的中央和地方的矛盾以及固有的满汉矛盾不断加剧甚至激化,在辛亥革命前夕严重动摇了清王朝的统治。  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