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   91435篇
  免费   2954篇
  国内免费   3篇
管理学   12485篇
民族学   553篇
人才学   26篇
人口学   7085篇
丛书文集   536篇
教育普及   2篇
理论方法论   9519篇
综合类   2129篇
社会学   43182篇
统计学   18875篇
  2023年   515篇
  2021年   577篇
  2020年   1522篇
  2019年   2247篇
  2018年   2093篇
  2017年   3170篇
  2016年   2393篇
  2015年   2071篇
  2014年   2647篇
  2013年   18976篇
  2012年   2390篇
  2011年   2179篇
  2010年   1975篇
  2009年   2202篇
  2008年   2070篇
  2007年   1899篇
  2006年   2083篇
  2005年   2338篇
  2004年   2229篇
  2003年   1900篇
  2002年   2021篇
  2001年   2042篇
  2000年   1818篇
  1999年   1725篇
  1998年   1510篇
  1997年   1361篇
  1996年   1332篇
  1995年   1345篇
  1994年   1319篇
  1993年   1298篇
  1992年   1302篇
  1991年   1242篇
  1990年   1215篇
  1989年   1064篇
  1988年   1144篇
  1987年   1014篇
  1986年   915篇
  1985年   1069篇
  1984年   1167篇
  1983年   1043篇
  1982年   962篇
  1981年   872篇
  1980年   823篇
  1979年   896篇
  1978年   798篇
  1977年   711篇
  1976年   663篇
  1975年   641篇
  1974年   531篇
  1973年   460篇
排序方式: 共有10000条查询结果,搜索用时 875 毫秒
801.
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   
802.
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   
803.
804.
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   
805.
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   
806.
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   
807.
808.
The weaknesses of established model selection procedures based on hypothesis testing and similar criteria are discussed and an alternative based on synthetic (composite) estimation is proposed. It is developed for the problem of prediction in ordinary regression and its properties are explored by simulations for the simple regression. Extensions to a general setting are described and an example with multiple regression is analysed. Arguments are presented against using a selected model for any inferences.  相似文献   
809.
Public and private funding sources often require nonprofit organizations to provide evidence of partnership with a governmental entity before financing a project. However, the circumstances under which working partnerships between the nonprofit and public sectors are forged and sustained have not been fully studied. This article presents the findings of a case study of land trusts and local governments and identifies conditions that foster successful collaboration. Social factors such as experience on the part of key personnel in working with the opposite entity and genuine affection for each other are more important than economic benefits. This suggests that a nonprofit agency interested in creating a viable partnership to improve a project should give careful consideration to assigning staff.  相似文献   
810.
The Access/Impact Problem and the Green and Gold Roads to Open Access   总被引:3,自引:0,他引:3  
The research access/impact problem arises because journal articles are not accessible to all of their would-be users; hence, they are losing potential research impact. The solution is to make all articles Open Access (OA; i.e., accessible online, free for all). OA articles have significantly higher citation impact than non-OA articles. There are two roads to OA: the “golden” road (publish your article in an OA journal) and the “green” road (publish your article in a non-OA journal but also self-archive it in an OA archive). Only 5% of journals are gold, but over 90% are already green (i.e., they have given their authors the green light to self-archive); yet only about 10–20% of articles have been self-archived. To reach 100% OA, self-archiving needs to be mandated by researchers' employers and funders, as the United Kingdom and the United States have recently recommended, and universities need to implement that mandate.  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