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   92276篇
  免费   2941篇
  国内免费   4篇
管理学   12718篇
民族学   542篇
人才学   25篇
人口学   7289篇
丛书文集   527篇
教育普及   2篇
理论方法论   9492篇
现状及发展   1篇
综合类   2182篇
社会学   43489篇
统计学   18954篇
  2023年   506篇
  2021年   570篇
  2020年   1517篇
  2019年   2211篇
  2018年   2124篇
  2017年   3193篇
  2016年   2412篇
  2015年   2064篇
  2014年   2639篇
  2013年   18872篇
  2012年   2446篇
  2011年   2276篇
  2010年   2006篇
  2009年   2203篇
  2008年   2063篇
  2007年   1890篇
  2006年   2132篇
  2005年   2316篇
  2004年   2185篇
  2003年   1927篇
  2002年   2025篇
  2001年   2104篇
  2000年   1894篇
  1999年   1765篇
  1998年   1532篇
  1997年   1406篇
  1996年   1364篇
  1995年   1373篇
  1994年   1336篇
  1993年   1330篇
  1992年   1340篇
  1991年   1268篇
  1990年   1239篇
  1989年   1093篇
  1988年   1184篇
  1987年   1044篇
  1986年   952篇
  1985年   1116篇
  1984年   1179篇
  1983年   1061篇
  1982年   978篇
  1981年   878篇
  1980年   826篇
  1979年   908篇
  1978年   793篇
  1977年   714篇
  1976年   664篇
  1975年   646篇
  1974年   536篇
  1973年   457篇
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
801.
我国高等教育面临着加入WTO后教育国际化、人才国际化的挑战,同时高等教育还因由计划经济、高校扩招、大学转型及办学模式多样化等方面的影响而导致质量下降,这就不得不使我们对我国高等教育质量的提高问题进行深入思考,并力求找出解决问题的办法。本文从六个方面给出了解决问题的具体措施。  相似文献   
802.
803.
We consider the problem of density estimation when the data is in the form of a continuous stream with no fixed length. In this setting, implementations of the usual methods of density estimation such as kernel density estimation are problematic. We propose a method of density estimation for massive datasets that is based upon taking the derivative of a smooth curve that has been fit through a set of quantile estimates. To achieve this, a low-storage, single-pass, sequential method is proposed for simultaneous estimation of multiple quantiles for massive datasets that form the basis of this method of density estimation. For comparison, we also consider a sequential kernel density estimator. The proposed methods are shown through simulation study to perform well and to have several distinct advantages over existing methods.  相似文献   
804.
In conjunction with TIMET at Waunarlwydd (Swansea, UK) a model has been developed that will optimise the scheduling of various blooms to their eight furnaces so as to minimise the time taken to roll these blooms into the finished mill products. This production scheduling model requires reliable data on times taken for the various furnaces that heat the slabs and blooms to reach the temperatures required for rolling. These times to temperature are stochastic in nature and this paper identifies the distributional form for these times using the generalised F distribution as a modelling framework. The times to temperature were found to be similarly distributed over all furnaces. The identified distributional forms were incorporated into the scheduling model to optimise a particular campaign that was run at TIMET Swansea. Amongst other conclusion it was found that, compared to the actual campaign, the model produced a schedule that reduced the makespan by some 35%.  相似文献   
805.
Recent social changes have made husbands' emotional investments and wives' perceptions of equity in the division of housework crucial for women's marital happiness. But wives are also happiest in their marriages when they share a strong normative commitment to lifelong marriage with their husbands and when their husbands take the lead in breadwinning. Thus our research suggests that elements of the new and the old promote marital happiness among contemporary wives.  相似文献   
806.
807.
Many observers doubt the capacity of digital media to change the political game. The rise of a transnational activism that is aimed beyond states and directly at corporations, trade and development regimes offers a fruitful area for understanding how communication practices can help create a new politics. The Internet is implicated in the new global activism far beyond merely reducing the costs of communication, or transcending the geographical and temporal barriers associated with other communication media. Various uses of the Internet and digital media facilitate the loosely structured networks, the weak identity ties, and the patterns of issue and demonstration organizing that define a new global protest politics. Analysis of various cases shows how digital network configurations can facilitate: permanent campaigns; the growth of broad networks despite relatively weak social identity and ideology ties; transformation of individual member organizations and whole networks; and the capacity to communicate messages from desktops to television screens. The same qualities that make these communication-based politics durable also make them vulnerable to problems of control, decision-making and collective identity.  相似文献   
808.
The evaluation of DNA evidence in pedigrees requiring population inference   总被引:1,自引:0,他引:1  
Summary. The evaluation of nuclear DNA evidence for identification purposes is performed here taking account of the uncertainty about population parameters. Graphical models are used to detail the hypotheses being debated in a trial with the aim of obtaining a directed acyclic graph. Graphs also clarify the set of evidence that contributes to population inferences and they also describe the conditional independence structure of DNA evidence. Numerical illustrations are provided by re-examining three case-studies taken from the literature. Our calculations of the weight of evidence differ from those given by the authors of case-studies in that they reveal more conservative values.  相似文献   
809.
810.
The Personal Responsibility and Work Opportunity Act of 1996 created a paradigm shift in the financing, organization, and delivery of welfare programs in the United States. The act shifted revenue and authority to states, giving them great discretion to determine the specifics of their programs. First‐order devolution, combined with time limits and work requirements, set in motion a chain of events that moved Temporary Assistance to Needy Families (TANF) recipients into the labor force and off state welfare rolls. Second‐order devolution shifted revenue and authority to community‐based organizations (CBOs) to help former recipients remain employed, advance to higher paying jobs, and move their families toward economic self‐sufficiency. Early findings from project innovations in Texas and other states raise doubts about the capacity of these organizations to achieve these goals. State funders will need to provide ongoing technical assistance and support to “scale up” the capacity of CBOs to plan, implement, and manage local innovations in welfare reform.  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