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   89280篇
  免费   2933篇
  国内免费   5篇
管理学   12304篇
民族学   544篇
人才学   26篇
人口学   6822篇
丛书文集   534篇
理论方法论   9342篇
综合类   2192篇
社会学   41734篇
统计学   18720篇
  2023年   502篇
  2021年   571篇
  2020年   1504篇
  2019年   2205篇
  2018年   2052篇
  2017年   3115篇
  2016年   2372篇
  2015年   2035篇
  2014年   2617篇
  2013年   18800篇
  2012年   2328篇
  2011年   2138篇
  2010年   1962篇
  2009年   2184篇
  2008年   2010篇
  2007年   1842篇
  2006年   2082篇
  2005年   2272篇
  2004年   2141篇
  2003年   1864篇
  2002年   1971篇
  2001年   1966篇
  2000年   1746篇
  1999年   1653篇
  1998年   1486篇
  1997年   1323篇
  1996年   1305篇
  1995年   1314篇
  1994年   1281篇
  1993年   1272篇
  1992年   1251篇
  1991年   1184篇
  1990年   1160篇
  1989年   1005篇
  1988年   1109篇
  1987年   977篇
  1986年   863篇
  1985年   1046篇
  1984年   1105篇
  1983年   995篇
  1982年   922篇
  1981年   837篇
  1980年   799篇
  1979年   862篇
  1978年   760篇
  1977年   685篇
  1976年   647篇
  1975年   627篇
  1974年   510篇
  1973年   436篇
排序方式: 共有10000条查询结果,搜索用时 828 毫秒
301.
UNDERSTANDING THE DECISION TO PARTICIPATE IN A SURVEY   总被引:18,自引:1,他引:17  
The lack of full participation in sample surveys threatens theinferential value of the survey method. We review a set of conceptualdevelopments and experimental findings that appear to be informativeabout causes of survey participation; offer an integration ofthat work with findings from the more traditional statisticaland survey methodological literature on nonresponse; and, giventhe theoretical structure, deduce potentially promising pathsof research toward the understanding of survey participation.  相似文献   
302.
In our zeal to deal with alcohol and drug abuse, we may have a distorted picture of what the majority of college students actually think about alcohol and drug use. Students in this study done at a public university located in the Deep South report being generally intolerant of substance abuse.  相似文献   
303.
304.
305.
The study reported describes Efe (pygmy) forager one-, two-, and three-year-olds' involvement with males. The Efe of northeastern Zaïre were chosen because their social organization allows us to examine hypotheses based on studies in Western, technologically complex societies about the distinctive role fathers play in the lives of their young children. Behavioral observations of Efe children's day-to-day activities with fathers, men and boys were recorded using a focal subject sampling technique (Altmann, 1974). Two behavioral measures were created to capture the extent to which males were involved with children: Social engagement describes males' involvement with children and social attention describes eavesdropping by children on males' everyday activities. Eight one-year-olds, 7 two-year-olds and 8 three-year-olds were each observed for six, one-hour observation sessions that were distributed evenly over the daylight hours. Data were analyzed using the traditional measure of involvement (e.g., adult males) and using a newly developed measure of the involvement of the average individual (e.g., average adult mate). Comparisons at each of the ages showed that fathers were consistently like other men in the extent to which children participated in social activities with them and watched their activities. Only fathers' level of social engagement declined significantly as children grew older. Boys' role relative to other males became increasingly distinctive as children aged. The findings suggest that Efe fathers may not be unique in the same sense assumed by Western study ideals, and raise questions about the special status given to fathers in Western theory and data. The patterning of mate involvement with children is discussed in terms of Efe community life, and in terms of Efe children's developing understanding of their relationship with fathers and other males.  相似文献   
306.
307.
This paper discusses some uses in econometrics of empirical process theory for dependent rendom variables. Examples considered include non-standard parametric hypotheses tests and semiparametric estimation. The application of bracketing functional limit results is discussed in some detail  相似文献   
308.
I test the hypothesis that the growth of autonomy was the factor responsible for the decline of marital fertility in eight Eastern European countries. By growth of autonomy I mean increased control over one's political, personal, religious, economic and reproductive life. This increased control was manifested in revolutions, democratic political reforms, nationalist movements and declining marital fertility. The political reforms were the result of the growth of autonomy but they also accelerated the dissemination of these new ideas among the populace contributing to further growth of autonomy. My hypothesis is generally supported by the historical data.  相似文献   
309.
Ohne Zusammenfassung German translations by Monika Lütke-Daldrup.  相似文献   
310.
Summary Meta-analyses of sets of clinical trials often combine risk differences from several 2×2 tables according to a random-effects model. The DerSimonian-Laird random-effects procedure, widely used for estimating the populaton mean risk difference, weights the risk difference from each primary study inversely proportional to an estimate of its variance (the sum of the between-study variance and the conditional within-study variance). Because those weights are not independent of the risk differences, however, the procedure sometimes exhibits bias and unnatural behavior. The present paper proposes a modified weighting scheme that uses the unconditional within-study variance to avoid this source of bias. The modified procedure has variance closer to that available from weighting by ideal weights when such weights are known. We studied the modified procedure in extensive simulation experiments using situations whose parameters resemble those of actual studies in medical research. For comparison we also included two unbiased procedures, the unweighted mean and a sample-size-weighted mean; their relative variability depends on the extent of heterogeneity among the primary studies. An example illustrates the application of the procedures to actual data and the differences among the results. This research was supported by Grant HS 05936 from the Agency for Health Care Policy and Research to Harvard University.  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