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   9353篇
  免费   179篇
  国内免费   1篇
管理学   1241篇
民族学   54篇
人才学   1篇
人口学   921篇
丛书文集   46篇
理论方法论   854篇
现状及发展   1篇
综合类   104篇
社会学   4664篇
统计学   1647篇
  2023年   59篇
  2021年   62篇
  2020年   144篇
  2019年   199篇
  2018年   238篇
  2017年   326篇
  2016年   251篇
  2015年   189篇
  2014年   219篇
  2013年   1683篇
  2012年   305篇
  2011年   295篇
  2010年   194篇
  2009年   189篇
  2008年   225篇
  2007年   193篇
  2006年   223篇
  2005年   194篇
  2004年   185篇
  2003年   170篇
  2002年   199篇
  2001年   204篇
  2000年   201篇
  1999年   198篇
  1998年   158篇
  1997年   146篇
  1996年   147篇
  1995年   134篇
  1994年   127篇
  1993年   122篇
  1992年   130篇
  1991年   150篇
  1990年   145篇
  1989年   159篇
  1988年   96篇
  1987年   124篇
  1986年   101篇
  1985年   132篇
  1984年   108篇
  1983年   117篇
  1982年   94篇
  1981年   96篇
  1980年   89篇
  1979年   92篇
  1978年   93篇
  1977年   66篇
  1976年   77篇
  1975年   70篇
  1974年   63篇
  1973年   50篇
排序方式: 共有9533条查询结果,搜索用时 4 毫秒
1.
2.
3.
4.
Service-learning programs are not free from challenges brought about by lack of financial support, lack of widespread commitment from professors, community agencies, and recipients of service, and lack of knowledge and insight in students directly involved in such programs. While service-learning initiatives and programs serve positive functions for organizations and individuals, rhetorical accolades for service learning can distort or omit the realities of program implementation and sustained delivery. This paper specifically explores the following challenges connected to service-learning programs: (1) pedagogical difficulties; (2) student limitations; (3) time constraints; and (4) community cooperation.  相似文献   
5.
6.
Spatial variation in soil inorganic nitrogen across an arid urban ecosystem   总被引:4,自引:1,他引:3  
We explored variations in inorganic soil nitrogen (N) concentrations across metropolitan Phoenix, Arizona, and the surrounding desert using a probability-based synoptic survey. Data were examined using spatial statistics on the entire region, as well as for the desert and urban sites separately. Concentrations of both NO3-N and NH4-N were markedly higher and more heterogeneous amongst urban compared to desert soils. Regional variation in soil NO3-N concentration was best explained by latitude, land use history, population density, along with percent cover of impervious surfaces and lawn, whereas soil NH4-N concentrations were related to only latitude and population density. Within the urban area, patterns in both soil NO3-N and NH4-N were best predicted by elevation, population density and type of irrigation in the surrounding neighborhood. Spatial autocorrelation of soil NO3-N concentrations explained 49% of variation among desert sites but was absent between urban sites. We suggest that inorganic soil N concentrations are controlled by a number of ‘local’ or ‘neighborhood’ human-related drivers in the city, rather than factors related to an urban-rural gradient.  相似文献   
7.
8.
The Coase theorem maintains that where free-market precepts exist, the allocation of property rights does not impact the distribution of resources. An application to Major League Baseball suggests that institutions such as free agency and the reverse-order amateur draft would not impact player distributions and therefore would not impact competitive balance. The present study finds that the distribution of wins is generally consistent with the precepts of the Coase theorem and therefore suggests a course for those who wish to alter the level of competitive balance: Major League Baseball should increase its focus on expanding the size of its labor pool. (JEL O15 , L83 , C22 )  相似文献   
9.
UNDERSTANDING THE DECISION TO PARTICIPATE IN A SURVEY   总被引:18,自引:1,他引:17  
The lack of full participation in sample surveys threatens theinferential value of the survey method. We review a set of conceptualdevelopments and experimental findings that appear to be informativeabout causes of survey participation; offer an integration ofthat work with findings from the more traditional statisticaland survey methodological literature on nonresponse; and, giventhe theoretical structure, deduce potentially promising pathsof research toward the understanding of survey participation.  相似文献   
10.
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