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   23733篇
  免费   406篇
  国内免费   15篇
管理学   3175篇
民族学   170篇
人才学   1篇
人口学   3508篇
丛书文集   147篇
理论方法论   1731篇
综合类   971篇
社会学   11474篇
统计学   2977篇
  2023年   72篇
  2021年   107篇
  2020年   213篇
  2019年   260篇
  2018年   1952篇
  2017年   2096篇
  2016年   1366篇
  2015年   300篇
  2014年   355篇
  2013年   2141篇
  2012年   804篇
  2011年   1593篇
  2010年   1412篇
  2009年   1104篇
  2008年   1220篇
  2007年   1408篇
  2006年   427篇
  2005年   589篇
  2004年   549篇
  2003年   486篇
  2002年   371篇
  2001年   358篇
  2000年   302篇
  1999年   290篇
  1998年   208篇
  1997年   174篇
  1996年   191篇
  1995年   177篇
  1994年   167篇
  1993年   174篇
  1992年   196篇
  1991年   203篇
  1990年   188篇
  1989年   163篇
  1988年   184篇
  1987年   196篇
  1986年   150篇
  1985年   164篇
  1984年   180篇
  1983年   157篇
  1982年   160篇
  1981年   128篇
  1980年   116篇
  1979年   127篇
  1978年   101篇
  1977年   82篇
  1976年   100篇
  1975年   115篇
  1974年   88篇
  1972年   64篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
991.
Previous studies have found that educational differences in mortality are weaker among the elderly. In this study I examine whether either cohort or period effects may have influenced the interpretation of age effects. Six 10-year birth cohorts are followed over 30 years through decennial censuses. Differential survival is inferred from changes in the relative proportions of a cohort in each education category as the cohort ages. In cross-section, younger persons generally show stronger education effects on survival, although this pattern is clearer for women than for men. There is evidence of period effects. Within cohorts, relative survival tends to increase with age.  相似文献   
992.
993.
User information satisfaction (UIS) is important because of its potential effects on MIS department goals, quality of user work life, and extent of voluntary usage of systems. Reliable measurement of UIS is important for providing evaluative information for both researchers and practitioners. This study used 92 managers and executives as subjects to compare the test/retest reliability of a widely used, 13-scale UIS instrument together with four summary questions under experimental and control conditions. The summary questions behaved more reliably than the detailed questions for all groups, perhaps because of problems with scale units and origins and with item heterogeneity. This suggests that researchers need more reliable measures of UIS and that practitioners need to exercise caution when collecting and interpreting UIS scores.  相似文献   
994.
Two heuristics based on branch and bound (B&B) are developed to solve closed-loop material requirements planning (MRP) lot-sizing problems that have general product structures and variable costs. A “look ahead method'’(LAM) heuristic allows for variable production/purchasing costs and uses a single-level B&B procedure to rapidly improve lower bound values; thus, LAM efficiently uses computer-storage capacity and allows solution of larger problems. The “total average modification'’(TAM) heuristic uses B&B, applied level by level, and modified setup and carrying costs to solve the variable production/purchasing costs MRP lot-sizing problem. LAM and TAM are tested on problems and compared to heuristics in the literature. TAM may be used to solve large MRP lot-sizing problems encountered in practice.  相似文献   
995.
Abstract Recent initiatives from state and federal government agencies have helped foster the formation of community‐based watershed organizations. Although there is a great deal of enthusiasm about the potential of these organizations to enhance water quality, relatively little attention has been paid to the impacts these organizations may have on the well‐being of rural communities more generally. Assessments of effectiveness have typically focused on specific activities and accomplishments, rather than a broader range of community‐based effects. In short, we ask whether community‐based environmental management improves community as well as environment. Our research utilized a mixed‐methods design, including a statewide mail survey of all Pennsylvania watershed organizations, followed by in‐depth interviews with 28 rural watershed organizations. This sequential approach progressively explored in more detail definitions of effectiveness, including the building of rural capacity. We find watershed organizations are potentially effective mechanisms for building local leadership, enhancing the skills of rural residents, and making valuable connections with other communities, facing similar water‐resource and rural‐development issues. However, the range of issues with which local watershed organizations engage and the methods they currently utilize may eventually limit their usefulness.  相似文献   
996.
Abstract This research examines differences between those Mexican migrants choosing metropolitan destinations and those choosing destinations outside metropolitan areas of the United States. Using general estimating equations, the study presents data indicating that since the 1960s migrants choosing rural destinations are less fluent in English, slightly older, much less educated, far more likely to be unskilled, more likely to be married, and more likely to be undocumented. The picture is more complex when consideration is restricted to those migrants arriving in rural areas since the passage of the North American Free Trade Agreement. These migrants are far more likely to be single, have more education but have less English fluency, have less work experience, and have less family experience with migration to the United States. They are more likely to come from small towns and rural areas of Mexico.  相似文献   
997.
This paper explores roles that children play in ethnographic research. Based on the limited literature on children in the field, and drawing on examples from ethnographies across disciplines, I identify four roles for children: 1) as “wedges,” or as instrumentally important in helping adult ethnographers gain access in various ways; 2) as collaborators; 3) as objects of study; and 4) as subjects of study. I also discuss the ways in which these roles illuminate key methodological issues in ethnography, like reflexivity, ethics, and agency. The paper synthesizes and integrates previously disconnected research on the presence of children in the field with ethnographies in which children and childhood are the topics of research. I draw on my own fieldwork experiences for further illustration.
Hilary LeveyEmail:

Hilary Levey   is a PhD candidate in sociology at Princeton University. Her research interests include childhood, culture, gender, and qualitative methods, and her dissertation is an ethnography of competitive children’s activities, with a focus on elementary school-age children’s participation in chess, dance, and soccer. She has previously studied child beauty pageants and Kumon Math and Reading Centers.  相似文献   
998.
This paper studies a class of social welfare relations (SWRs) on the set of infinite utility streams. In particular, we examine the SWRs satisfying -Anonymity, an impartiality axiom stronger than Finite Anonymity, as well as Strong Pareto and a certain equity axiom. First, we characterize the extension of the generalized Lorenz SWR by combining -Anonymity with Strong Pareto and Pigou–Dalton Equity. Second, we replace Pigou–Dalton Equity with Hammond Equity for characterizing the extended leximin SWR. Third, we give an alternative characterization of the extended utilitarian SWR by substituting Incremental Equity for Pigou–Dalton Equity.  相似文献   
999.
We consider the fraction of pairs of m distinct alternatives on which a social welfare function f may be nondictatorially independent and Pareto when the domain of f satisfies the free k-tuple property. When k = 4 we improve the existing upper bound to . When there are at least 26 alternatives and we obtain an original upper bound, . To obtain these results we define and analyze the graph formed from the nondictatorial independent and Pareto pairs and combine the results of this analysis with known results from extremal graph theory. The authors extend special thanks to the two reviewers and the editor for their comments.  相似文献   
1000.
We study necessary and sufficient conditions for a multi-valued solution S to be rationalized in the following sense: there exists a complete asymmetric relation T (a tournament) such that, for each feasible (finite) set, the solution set of S coincides with the minimal covering set of T restricted to that feasible set. Our characterization result relies only on properties relating S across feasible choice sets.  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