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   94617篇
  免费   2008篇
  国内免费   3篇
管理学   12866篇
民族学   563篇
人才学   26篇
人口学   7302篇
丛书文集   531篇
教育普及   1篇
理论方法论   9755篇
综合类   2178篇
社会学   44204篇
统计学   19202篇
  2023年   522篇
  2021年   583篇
  2020年   1547篇
  2019年   2251篇
  2018年   2181篇
  2017年   3281篇
  2016年   2523篇
  2015年   2107篇
  2014年   2684篇
  2013年   19089篇
  2012年   2599篇
  2011年   2404篇
  2010年   2092篇
  2009年   2263篇
  2008年   2184篇
  2007年   1999篇
  2006年   2209篇
  2005年   2370篇
  2004年   2246篇
  2003年   1980篇
  2002年   2076篇
  2001年   2103篇
  2000年   1870篇
  1999年   1762篇
  1998年   1555篇
  1997年   1413篇
  1996年   1370篇
  1995年   1392篇
  1994年   1327篇
  1993年   1326篇
  1992年   1335篇
  1991年   1265篇
  1990年   1247篇
  1989年   1072篇
  1988年   1158篇
  1987年   1023篇
  1986年   926篇
  1985年   1125篇
  1984年   1171篇
  1983年   1035篇
  1982年   956篇
  1981年   874篇
  1980年   823篇
  1979年   900篇
  1978年   790篇
  1977年   716篇
  1976年   671篇
  1975年   634篇
  1974年   536篇
  1973年   451篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
181.
VII. Conclusion The number of immigrants now coming to the United States is proportionally only a fraction of the number that came in earlier years, and there is nothing in those numbers to suggest a difficult absorption burden. Immigrants, both legal and illegal, more than pay for the services they use with the taxes they pay, leaving a considerable net surplus that benefits American citizens. Immigrants raise productivity and do not cause an observable amount of unemployment of citizens. Admitting far more immigrants into the country than the law now allows would have positive effects on the incomes of citizens, and would enhance the continuing vitality of the United States.  相似文献   
182.
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   
183.
184.
185.
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   
186.
187.
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   
188.
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   
189.
Ohne Zusammenfassung German translations by Monika Lütke-Daldrup.  相似文献   
190.
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