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   20461篇
  免费   612篇
  国内免费   1篇
管理学   2855篇
民族学   76篇
人才学   2篇
人口学   2000篇
丛书文集   85篇
教育普及   2篇
理论方法论   1945篇
现状及发展   1篇
综合类   272篇
社会学   10222篇
统计学   3614篇
  2023年   98篇
  2021年   120篇
  2020年   321篇
  2019年   424篇
  2018年   506篇
  2017年   687篇
  2016年   543篇
  2015年   394篇
  2014年   499篇
  2013年   3247篇
  2012年   685篇
  2011年   675篇
  2010年   488篇
  2009年   411篇
  2008年   504篇
  2007年   513篇
  2006年   511篇
  2005年   487篇
  2004年   456篇
  2003年   409篇
  2002年   447篇
  2001年   547篇
  2000年   544篇
  1999年   472篇
  1998年   353篇
  1997年   321篇
  1996年   329篇
  1995年   310篇
  1994年   295篇
  1993年   307篇
  1992年   352篇
  1991年   322篇
  1990年   297篇
  1989年   296篇
  1988年   295篇
  1987年   257篇
  1986年   251篇
  1985年   285篇
  1984年   275篇
  1983年   259篇
  1982年   217篇
  1981年   189篇
  1980年   169篇
  1979年   197篇
  1978年   179篇
  1977年   160篇
  1976年   135篇
  1975年   161篇
  1974年   120篇
  1973年   115篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
MODEL-ASSISTED HIGHER-ORDER CALIBRATION OF ESTIMATORS OF VARIANCE   总被引:1,自引:0,他引:1  
In survey sampling, interest often centres on inference for the population total using information about an auxiliary variable. The variance of the estimator used plays a key role in such inference. This study develops a new set of higher‐order constraints for the calibration of estimators of variance for various estimators of the population total. The proposed strategy requires an appropriate model for describing the relationship between the response and auxiliary variable, and the variance of the auxiliary variable. It is therefore referred to as a model‐assisted approach. Several new estimators of variance, including the higher‐order calibration estimators of the variance of the ratio and regression estimators suggested by Singh, Horn & Yu and Sitter & Wu are special cases of the proposed technique. The paper presents and discusses the results of an empirical study to compare the performance of the proposed estimators and existing counterparts.  相似文献   
82.
83.
84.
85.
86.
Banks winners in tournaments are difficult to recognize   总被引:1,自引:0,他引:1  
Given a tournament T, a Banks winner of T is the top vertex of any maximal (with respect to inclusion) transitive subtournament of T. In this technical note, we show that the problem of deciding whether some fixed vertex v is a Banks winner for T is NP-complete. Received: 22 February 2002/Accepted: 20 June 2002 Supported by the START program Y43-MAT of the Austrian Ministry of Science. I would like to thank two thank the referees for a careful reading of the paper, for helpful remarks, and for many suggestions how to improve the presentation.  相似文献   
87.
Using data from 8 random assignment studies and employing meta‐analytic techniques, this article provides systematic evidence that welfare and work policies targeted at low‐income parents have small adverse effects on some school outcomes among adolescents ages 12 to 18 years at follow‐up. These adverse effects were observed mostly for school performance outcomes and occurred in programs that required mothers to work or participate in employment‐related activities and those that encouraged mothers to work voluntarily. The most pronounced negative effects on school outcomes occurred for the group of adolescents who had a younger sibling, possibly because of the increased home and sibling care responsibilities they assumed as their mothers increased their employment.  相似文献   
88.
Using an experimental design, this research examines the effect of the nation's first family cap on the births, abortions, and contraception use of over 8,000 women receiving public assistance in New Jersey. The family cap denies additional cash benefits to children conceived while the mother is receiving public assistance. Our research shows that a targeted welfare benefit manipulation does influence fertility behavior; however, the effect is conditioned by race. We find that Black women in the experimental group have a 21% lower birth rate and a 32% higher abortion rate than Black women in the control group. We do not find a birth effect for Hispanic or White women. We discuss the policy implications of the effects of a segmented family cap.  相似文献   
89.
This article aims to bring gender into an even tighter transnational migration focus by broadening and deepening our original framework of “gendered geographies of power,” linking it more directly to existing and emerging scholarship. We examine and highlight previously neglected areas such as the role of the state and the social imaginary in gendering transnational processes and experiences. We identify topics that remain under‐appreciated, under‐researched, and/or under‐theorized. Finally, we initiate a discussion of how a gendered analysis of transnational migration can help bridge this particular research to other gendered transnational processes under study that do not privilege migration.  相似文献   
90.
Testing symmetry under a skew Laplace model   总被引:3,自引:0,他引:3  
We develop tests of hypothesis about symmetry based on samples from possibly asymmetric Laplace distributions and present exact and limiting distribution of the test statistics. We postulate that the test statistic derived under the Laplace model is a rational choice as a measure of skewness and can be used in testing symmetry for other, quite general classes of skew distributions. Our results are applied to foreign exchange rates for 15 currencies.  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