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   880篇
  免费   44篇
管理学   148篇
民族学   8篇
人才学   1篇
人口学   65篇
丛书文集   3篇
理论方法论   113篇
综合类   8篇
社会学   520篇
统计学   58篇
  2024年   1篇
  2023年   4篇
  2022年   4篇
  2021年   9篇
  2020年   15篇
  2019年   37篇
  2018年   35篇
  2017年   46篇
  2016年   43篇
  2015年   40篇
  2014年   35篇
  2013年   147篇
  2012年   45篇
  2011年   29篇
  2010年   27篇
  2009年   31篇
  2008年   31篇
  2007年   22篇
  2006年   15篇
  2005年   28篇
  2004年   27篇
  2003年   18篇
  2002年   32篇
  2001年   18篇
  2000年   11篇
  1999年   24篇
  1998年   16篇
  1997年   14篇
  1996年   13篇
  1995年   17篇
  1994年   12篇
  1993年   14篇
  1992年   11篇
  1991年   9篇
  1990年   4篇
  1989年   7篇
  1988年   4篇
  1986年   5篇
  1985年   4篇
  1984年   3篇
  1983年   1篇
  1982年   3篇
  1981年   4篇
  1980年   3篇
  1978年   1篇
  1976年   3篇
  1974年   1篇
  1971年   1篇
排序方式: 共有924条查询结果,搜索用时 17 毫秒
21.
22.
We present APproximated Exhaustive Search (APES), which enables fast and approximated exhaustive variable selection in Generalised Linear Models (GLMs). While exhaustive variable selection remains as the gold standard in many model selection contexts, traditional exhaustive variable selection suffers from computational feasibility issues. More precisely, there is often a high cost associated with computing maximum likelihood estimates (MLE) for all subsets of GLMs. Efficient algorithms for exhaustive searches exist for linear models, most notably the leaps‐and‐bound algorithm and, more recently, the mixed integer optimisation (MIO) algorithm. The APES method learns from observational weights in a generalised linear regression super‐model and reformulates the GLM problem as a linear regression problem. In this way, APES can approximate a true exhaustive search in the original GLM space. Where exhaustive variable selection is not computationally feasible, we propose a best‐subset search, which also closely approximates a true exhaustive search. APES is made available in both as a standalone R package as well as part of the already existing mplot package.  相似文献   
23.
We examine how soda sales changed due to the campaign attention and election outcome of a local excise tax on sugar‐sweetened beverages. Using panel data of beverage sales from university retailers in Berkeley, California, we estimate that soda purchases relative to control beverages significantly dropped immediately after the election, months before the tax was implemented in the city of Berkeley or on campus. Supplemental scanner data from off‐campus retailers reveal this result is not unique to the university setting. Our findings suggest soda tax media coverage and election outcomes can have larger effects on purchasing behavior than the tax itself. (JEL D12, H20, C23, I38, Q18)  相似文献   
24.
In this study, I examine disparities in schooling progress among children born to immigrant and U.S.-born blacks. I find that in one- and two-parent families, children born to black immigrants are less likely to fall behind in school than those born to U.S.-born blacks. In two-parent immigrant families, children born to two immigrant parents have a significant schooling advantage over children born to one immigrant parent. While children born to two immigrant parents in the wealthiest black immigrant families do better in the second generation than in the first, the reverse is observed among children in less wealthy families. These findings contribute in two ways to our understanding of the assimilation processes of children born to black immigrant parents. First, they show that there is a positive association between the number of immigrant parents in a family and children’s schooling performance. Second, they suggest that disparities in the assimilation patterns of the children of black immigrants are a likely product of the interaction between their parental characteristics and the socioeconomic circumstances of their families.  相似文献   
25.
Criminologists have long reported the existence of racial disparity in the criminal justice system, but the important question is why. While some argue that observed differences are a consequence of more criminal behavior among minorities, the weight of the evidence indicates that this is but a partial explanation. In this paper, we study data from a sample of juveniles to examine how racial differences in early police contact, and important social environments—family, school, and neighborhoods—affect later contact and arrests, controlling for self-reported delinquency. We find that early (in middle school) contact with police is an important predictor of later (high school) arrests. Also we found that, in addition to being male and living in a low-income family, children who have parents who have a history of arrest, who have experienced school disciplinary actions, who have delinquent peers, and who are in networks with deviant adults are more likely to have problems with law enforcement. These factors help to explain racial differences in police contacts and arrests.  相似文献   
26.
For nearly four decades, child welfare policy and practice have focused on the achievement of legal permanence for children in foster care. Although federal child welfare policy has resulted in the movement of children from state custody to legally permanent adoptive or guardianship families, little is known about the quality and enduring nature of these placements. A significant challenge of the twenty-first century child welfare system is how to ensure the well-being of children currently living with adoptive parents or guardians. This paper discusses child welfare policy and trends related to post-permanency well-being, including the decrease in Title IV-E foster care caseloads nationwide and the simultaneous increase in Title IV-E adoptive and guardianship caseloads. We highlight the needs of a twenty-first century child welfare system, including increased federal efforts to ensure child permanence and well-being after legal adoption or guardianship has been achieved, as well as more rigorous longitudinal and interdisciplinary research focused on the post-permanency adjustment of children and their families.  相似文献   
27.
Limited empirical study of the career development of Asian Americans in general and Korean Americans in particular has been conducted. The authors present the results of a theory‐based exploration of the career goals of Korean American university students in which ethnic identity, self‐efficacy, outcome expectations, and career interests were used to predict goal intentions for science and nonscience careers. Outcome expectations and career interests predicted a moderate amount of variance in science career goal intentions and a moderate to large amount of variance in nonscience career goal intentions. Korean American students' career goal development seems similar to that of American college students.  相似文献   
28.
29.
The present paper develops and tests two temporal models of the relationships among adolescents' ethnic identity exploration, ethnic identity affirmation and belonging, and attitudes toward their racial/ethnic ingroup and outgroups. Structural equation models for Euro‐Americans, Asian Americans, and Latinos revealed that all hypothesized relationships were positive and significant. The model in which ethnic identity exploration (at Time 1) predicts ethnic identity affirmation and belonging (at Time 2) was superior to the alternative model in which the relationship between them was reversed (i.e., affirmation and belonging at Time 1 predicts exploration at Time 2). Results (1) support the importance of exploration as a basis for establishing a secure attachment to one's ethnic identity, which, in turn, has positive implications for attitudes toward one's own group and other groups and (2) suggest that maintenance of ethnic identity is compatible with positive attitudes toward ethnic outgroups.  相似文献   
30.
Urban biodiversity conservation needs a firm scientific foundation, one that draws upon active and regionally calibrated research programs. Until recently this foundation has not existed. In this paper we examine the way in which the emerging discipline of restoration ecology in an urban context can learn from the experiences of ongoing restoration projects and in turn how novel insights from research of urban soils can help these projects define and reach their goals. Limitations on collaboration between academic researchers and practitioners continues be problematic. We discuss a model whereby this impediment may be removed. A case study of Rhamnus cathartica, an invader of Midwestern woodlands which modifies some important soil ecosystem properties will be used to illustrate the potential for engagement between research and practice.  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