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   19816篇
  免费   363篇
  国内免费   1篇
管理学   2834篇
民族学   75篇
人才学   2篇
人口学   1911篇
丛书文集   78篇
教育普及   2篇
理论方法论   1789篇
现状及发展   1篇
综合类   262篇
社会学   9615篇
统计学   3611篇
  2021年   120篇
  2020年   291篇
  2019年   394篇
  2018年   464篇
  2017年   623篇
  2016年   496篇
  2015年   375篇
  2014年   484篇
  2013年   3092篇
  2012年   658篇
  2011年   642篇
  2010年   460篇
  2009年   395篇
  2008年   463篇
  2007年   475篇
  2006年   472篇
  2005年   451篇
  2004年   415篇
  2003年   386篇
  2002年   428篇
  2001年   529篇
  2000年   541篇
  1999年   463篇
  1998年   341篇
  1997年   312篇
  1996年   324篇
  1995年   303篇
  1994年   288篇
  1993年   292篇
  1992年   348篇
  1991年   322篇
  1990年   287篇
  1989年   293篇
  1988年   293篇
  1987年   253篇
  1986年   244篇
  1985年   279篇
  1984年   271篇
  1983年   255篇
  1982年   216篇
  1981年   182篇
  1980年   166篇
  1979年   194篇
  1978年   177篇
  1977年   161篇
  1976年   134篇
  1975年   158篇
  1974年   119篇
  1973年   117篇
  1972年   94篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
871.
As U.S. manufacturing and production industries have declined, the growth of the care sector has increasingly become an important source of jobs for workers without a college degree. Often requiring some form of postsecondary credentialing, many care occupations can provide better wages, job stability, and possible upward mobility for less educated workers. However, employment patterns in paid care work are both gendered and racialized: women and workers of color are overrepresented in care occupations with fewer entry barriers, benefits, and lower pay. Although these patterns are well documented, the mechanisms producing them are less well understood. Using event history analysis and the National Longitudinal Survey of Youth (NLSY79), this study evaluates the explanatory power of neoclassical economic, status attainment, and social closure theories of occupational segregation for black women’s and men’s greater hazard or “risk” of entering care occupations, relative to white workers. Net of individual and closure mechanisms, significant residual effects suggest labor market discrimination remains a primary explanation for the over-representation of black workers in less credentialed care jobs with fewer benefits.  相似文献   
872.
873.
Parental psychopathology and parenting behavior are known to be related to adolescents depression and anxiety, but unique roles of mothers and fathers are not clear. Our aim was to examine the relation of maternal and paternal psychopathology, emotional support, and respect for autonomy, and their interaction to depression and anxiety symptoms in adolescents. In total, 142 female adolescents participated, together with 138 mothers and 113 fathers. Data were analyzed using latent growth curve modeling. Paternal emotional support was negatively related to adolescent baseline level of depression and anxiety symptoms. Further, we found that there was a positive association between respect for autonomy and depression symptoms in adolescents for higher levels of paternal symptoms of psychological problems.  相似文献   
874.
The private nature of psychosexual functioning leads adolescents and their parents to have different perspectives, which highlights studying parent–child informant discrepancies in this domain. We investigated informant discrepancy in psychosexual functioning, using the self‐report and parent report versions of the Teen Transition Inventory (TTI), of adolescents with autism spectrum disorder (ASD; 136 parent–child dyads) compared to adolescents from the general population (GP; 70 parent–child dyads). Significantly larger informant discrepancies exist in ASD dyads than GP dyads in most domains of psychosexual functioning, except for Body image, Sexual behavior, and Confidence in the future. It is important to use and pay attention to both informants, as discrepancies are relevant for both research and clinical practice regarding psychosexual functioning.  相似文献   
875.
876.
Urban Ecosystems - Urban insect communities are structured by hierarchical filters including regional processes, human facilitation, and species interactions. We sought to inform future urban...  相似文献   
877.
878.
Likelihood-free methods such as approximate Bayesian computation (ABC) have extended the reach of statistical inference to problems with computationally intractable likelihoods. Such approaches perform well for small-to-moderate dimensional problems, but suffer a curse of dimensionality in the number of model parameters. We introduce a likelihood-free approximate Gibbs sampler that naturally circumvents the dimensionality issue by focusing on lower-dimensional conditional distributions. These distributions are estimated by flexible regression models either before the sampler is run, or adaptively during sampler implementation. As a result, and in comparison to Metropolis-Hastings-based approaches, we are able to fit substantially more challenging statistical models than would otherwise be possible. We demonstrate the sampler’s performance via two simulated examples, and a real analysis of Airbnb rental prices using a intractable high-dimensional multivariate nonlinear state-space model with a 36-dimensional latent state observed on 365 time points, which presents a real challenge to standard ABC techniques.  相似文献   
879.

Motivated by a breast cancer research program, this paper is concerned with the joint survivor function of multiple event times when their observations are subject to informative censoring caused by a terminating event. We formulate the correlation of the multiple event times together with the time to the terminating event by an Archimedean copula to account for the informative censoring. Adapting the widely used two-stage procedure under a copula model, we propose an easy-to-implement pseudo-likelihood based procedure for estimating the model parameters. The approach yields a new estimator for the marginal distribution of a single event time with semicompeting-risks data. We conduct both asymptotics and simulation studies to examine the proposed approach in consistency, efficiency, and robustness. Data from the breast cancer program are employed to illustrate this research.

  相似文献   
880.
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