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   19229篇
  免费   344篇
  国内免费   1篇
管理学   2773篇
民族学   69篇
人才学   1篇
人口学   1866篇
丛书文集   76篇
教育普及   2篇
理论方法论   1715篇
现状及发展   1篇
综合类   257篇
社会学   9285篇
统计学   3529篇
  2021年   112篇
  2020年   274篇
  2019年   374篇
  2018年   437篇
  2017年   599篇
  2016年   472篇
  2015年   347篇
  2014年   456篇
  2013年   2983篇
  2012年   630篇
  2011年   608篇
  2010年   443篇
  2009年   369篇
  2008年   441篇
  2007年   458篇
  2006年   452篇
  2005年   438篇
  2004年   401篇
  2003年   375篇
  2002年   417篇
  2001年   519篇
  2000年   529篇
  1999年   461篇
  1998年   339篇
  1997年   310篇
  1996年   321篇
  1995年   302篇
  1994年   283篇
  1993年   288篇
  1992年   342篇
  1991年   316篇
  1990年   286篇
  1989年   290篇
  1988年   288篇
  1987年   250篇
  1986年   243篇
  1985年   277篇
  1984年   266篇
  1983年   250篇
  1982年   215篇
  1981年   180篇
  1980年   164篇
  1979年   194篇
  1978年   176篇
  1977年   159篇
  1976年   134篇
  1975年   157篇
  1974年   118篇
  1973年   115篇
  1972年   93篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
391.
The utility of conventional project management techniques, such as PERT and CPM, is hampered by significant and realistic network attributes and managerial considerations. There are many situations which involve more than one project and numerous resources. Of major concern in such situations is the reduction of the maximum quantity of each required resource. The algorithm presented here is capable of scheduling the individual activities in multiple projects with multiple resources and leveling the overall quantity of each resource which is required. The basis of the algorithm is a sequencing procedure for examining various combinations of activity start times. The measure of effectiveness for each combination is the sum of the squares of the required quantity of each resource in each time period.  相似文献   
392.
本文介绍了蒙古尔部族的组成、形成和发展,并对其族长、土司的特点和承继作了详尽的描述。本文介绍了蒙古尔部族的组成、形成和发展,并对其族长、土司的特点和承继作了详尽的描述。  相似文献   
393.
本文对蒙古尔部族的组成、形成和发展作了介绍,其中对族长、土司的特点和承继作了详尽的描述。  相似文献   
394.
The present empirical study applies the methodology of information theory to the problem of assessing and separating capital market risk, which is separated into its systematic and unsystematic components. Monthly return relatives for all securities traded on the New York Stock Exchange are examined for the period 1926 to 1971, which is segmented into six 7-year subperiods. The securities are combined into portfolios of various sizes and ranked. It is concluded that although both systematic and unsystematic risks have increased over the 45-year interval—particularly between the pre-1940 and post-1940 periods—they have maintained their relative share of the total risk over the same period.  相似文献   
395.
This paper reports the results of three studies conducted to develop, refine, and validate a scale which assessed heterosexual adults' attitudes toward same-sex marriage, the Attitude Toward Same-Sex Marriage Scale (ASSMS). The need for such a scale is evidenced in the increasing importance of same-sex marriage in the political arena of the United States and other nations, as well as the growing body of empirical research examining same-sex marriage and related issues (e.g., Lannutti, 2005; Solomon, Rothblum, & Balsam, 2004). The results demonstrate strong reliability, convergent validity, and predictive validity for the ASSMS and suggest that the ASSMS may be adapted to measure attitudes toward civil unions and other forms of relational recognition for same-sex couples. Gender comparisons using the validated scale showed that in college and non-college samples, women had a significantly more positive attitude toward same-sex marriage than did men.  相似文献   
396.
397.
This paper considers a class of summary measures of the dependence between a pair of failure time variables over a finite follow-up region. The class consists of measures that are weighted averages of local dependence measures, and includes the cross-ratio-measure and finite region version of Kendall's τ; recently proposed by the authors. Two new special cases are identified that can avoid the need to estimate the bivariate survivor function and that admit explicit variance estimators. Nonparametric estimators of such dependence measures are proposed and are shown to be consistent and asymptotically normal with variances that can be consistently estimated. Properties of selected estimators are evaluated in a simulation study, and the method is illustrated through an analysis of Australian Twin Study data.  相似文献   
398.
In sequential studies, formal interim analyses are usually restricted to a consideration of a single null hypothesis concerning a single parameter of interest. Valid frequentist methods of hypothesis testing and of point and interval estimation for the primary parameter have already been devised for use at the end of such a study. However, the completed data set may warrant a more detailed analysis, involving the estimation of parameters corresponding to effects that were not used to determine when to stop, and yet correlated with those that were. This paper describes methods for setting confidence intervals for secondary parameters in a way which provides the correct coverage probability in repeated frequentist realizations of the sequential design used. The method assumes that information accumulates on the primary and secondary parameters at proportional rates. This requirement will be valid in many potential applications, but only in limited situations in survival analysis.  相似文献   
399.
After mindfulness is defined, a brief history of the research on the topic to date is reviewed. This work essentially falls into three categories: health, business, and education. Considerations of mindlessness as a social issue are then addressed. A brief introduction to the articles in this issue follows. These articles speak to mindfulness as it relates to potential solutions to social problems.  相似文献   
400.
We consider some of the ways in which mindfulness theory can provide new solutions to current problems and address potential future problems that may result from changes in demographics and technology. Specific research questions are suggested to see how increasing mindfulness and decreasing mindlessnesscan work to diminish these social problems as they occur specifically in the classroom, the workplace, and the social predicament of getting old. We discuss (a) recasting some of the problems of the elderly into problems of perspective about the elderly, (b) mindful ways of dealing with increased ethnic diversity, (c) differentiating between changing the workplace work and changing the character of the work itself and (d) the advantages and ways of increasingmindfulness in the classroom.  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