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   92904篇
  免费   2980篇
  国内免费   3篇
管理学   12716篇
民族学   572篇
人才学   26篇
人口学   7311篇
丛书文集   528篇
教育普及   1篇
理论方法论   9592篇
综合类   2152篇
社会学   43969篇
统计学   19020篇
  2023年   517篇
  2021年   583篇
  2020年   1543篇
  2019年   2252篇
  2018年   2167篇
  2017年   3257篇
  2016年   2478篇
  2015年   2086篇
  2014年   2673篇
  2013年   19008篇
  2012年   2557篇
  2011年   2384篇
  2010年   2071篇
  2009年   2232篇
  2008年   2171篇
  2007年   1981篇
  2006年   2179篇
  2005年   2345篇
  2004年   2225篇
  2003年   1956篇
  2002年   2056篇
  2001年   2087篇
  2000年   1853篇
  1999年   1748篇
  1998年   1542篇
  1997年   1388篇
  1996年   1355篇
  1995年   1379篇
  1994年   1315篇
  1993年   1311篇
  1992年   1327篇
  1991年   1263篇
  1990年   1235篇
  1989年   1068篇
  1988年   1154篇
  1987年   1017篇
  1986年   920篇
  1985年   1105篇
  1984年   1165篇
  1983年   1038篇
  1982年   948篇
  1981年   869篇
  1980年   816篇
  1979年   893篇
  1978年   796篇
  1977年   720篇
  1976年   662篇
  1975年   637篇
  1974年   527篇
  1973年   448篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
971.
972.
The mean density of bacteria in a water body is commonly monitored using quantal assay. This paper describes the use of local scoring in estimating the spatial distribution of mean density from quantal assay results at a set of point locations. An application to estimating the mean density of fecal conform bacteria in a coastal pond is presented. Model diagnostics based on a parametric bootstrap are also presented.  相似文献   
973.
The possibility that carbon dioxide emissions from fossil fuel use might lead to global warming has become a leading environmental concern. Many scientific and environmental organizations have called for immediate action to limit carbon dioxide production. For the most part, however, public debate has focused on a single policy instrument: a carbon tax applied to fossil fuels in proportion to their carbon content. We present a detailed model of the U.S. economy and use it to compare carbon taxes with two other instruments that could achieve the same reduction in carbon dioxide emissions: a tax on the energy content of fossil fuels (a BTU tax) and an ad valorem tax on fuel use. We find that carbon taxes can achieve a given reduction with the least overall effect on the economy, but with a large effect on coal mining. Energy taxes are fairly similar to carbon taxes but have slightly less impact on coal mining and slightly greater overall cost. In contrast, ad valorem taxes fall much more lightly on coal mining but have a much greater effect on the economy as a whole.  相似文献   
974.
975.
A training project in a northern Canadian community providedan opportunity to examine participatory planning approachesand the meaning of work in First Nations communities. Focusgroups conducted three years after the unsuccessful interventionof a community economic development (CED) project suggest thatcomplex factors such as lack of support from community leadersand rate of pay for workers determine whether CED is alwaysappropriate in northern, First Nations contexts.  相似文献   
976.
Given the fragmented structure of child‐care assistance in the United States, it has been difficult to obtain accurate estimates of which families are assisted, through which mechanisms, and at what level. Making use of survey data from New York City, we analyze the distribution of several forms of public child‐care assistance. Results suggest that about 40% of all families with young children receive some form of child‐care assistance. Considering all forms of assistance, the distribution of child‐care help is targeted in both expected and some unexpected ways. Implications of these results are discussed in the context of U.S. child‐care policies governing access and benefit levels.  相似文献   
977.
The authors consider the issue of map positional error, or the difference between location as represented in a spatial database (i.e., a map) and the corresponding unobservable true location. They propose a fully model‐based approach that incorporates aspects of the map registration process commonly performed by users of geographic informations systems, including rubber‐sheeting. They explain how estimates of positional error can be obtained, hence estimates of true location. They show that with multiple maps of varying accuracy along with ground truthing data, suitable model averaging offers a strategy for using all of the maps to learn about true location.  相似文献   
978.
The 1995 wave of the Add Health study is used to investigate the relative influence of parent gender and residence on patterns of parental involvement with adolescents. Adolescent reports (N =17,330) of shared activities, shared communication, and relationship quality with both biological parents are utilized. A multidimensional scaling analysis reveals that parent gender explains most of the variance in parent‐adolescent involvement, with residential status playing a secondary yet a fundamental role in accounting for these patterns. Resident mothers who do not live with adolescents’ biological fathers engage in the broadest range of activities with their children. Unpartnered resident fathers display patterns of parenting that are as similar to mothers as they are to other fathers.  相似文献   
979.
Ohne Zusammenfassung Rede zum 100. Geburtstag auf einer Veranstaltung der Stadt K?ln, der René-K?nig-Gesellschaft und des Westdeutschen Rundfunks K?ln am 11. Mai 2006 in K?ln  相似文献   
980.
The article tests the thesis that globalization increases the earnings inequality of households. It extends the time series data set of Alderson and Nielsen (2002) who supported the globalization thesis. Alternative models provide no evidence that foreign trade, foreign investment, and migration increase inequality. The article gives reasons for these results and shows that OECD countries pass through an endogenous sectoral and demographic crisis in the transition to post-industrial service societies. Therefore, the paper adapts Kuznets’ theorem of sector dualism to the subsectors of the service economy. The polarization of value addition within the service sector appears as the crucial determinant of increased earnings inequality of households.  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