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   8203篇
  免费   207篇
  国内免费   2篇
管理学   1247篇
民族学   31篇
人口学   724篇
丛书文集   26篇
理论方法论   746篇
综合类   94篇
社会学   4225篇
统计学   1319篇
  2020年   106篇
  2019年   134篇
  2018年   167篇
  2017年   195篇
  2016年   180篇
  2015年   132篇
  2014年   175篇
  2013年   1382篇
  2012年   215篇
  2011年   222篇
  2010年   172篇
  2009年   159篇
  2008年   201篇
  2007年   202篇
  2006年   213篇
  2005年   198篇
  2004年   165篇
  2003年   136篇
  2002年   159篇
  2001年   161篇
  2000年   181篇
  1999年   148篇
  1998年   141篇
  1997年   123篇
  1996年   128篇
  1995年   132篇
  1994年   140篇
  1993年   130篇
  1992年   141篇
  1991年   156篇
  1990年   173篇
  1989年   143篇
  1988年   157篇
  1987年   137篇
  1986年   133篇
  1985年   133篇
  1984年   145篇
  1983年   132篇
  1982年   97篇
  1981年   80篇
  1980年   87篇
  1979年   114篇
  1978年   89篇
  1977年   70篇
  1976年   82篇
  1975年   52篇
  1974年   75篇
  1973年   52篇
  1971年   43篇
  1970年   44篇
排序方式: 共有8412条查询结果,搜索用时 15 毫秒
61.
Summary. We propose a simple estimation procedure for a proportional hazards frailty regression model for clustered survival data in which the dependence is generated by a positive stable distribution. Inferences for the frailty parameter can be obtained by using output from Cox regression analyses. The computational burden is substantially less than that of the other approaches to estimation. The large sample behaviour of the estimator is studied and simulations show that the approximations are appropriate for use with realistic sample sizes. The methods are motivated by studies of familial associations in the natural history of diseases. Their practical utility is illustrated with sib pair data from Beaver Dam, Wisconsin.  相似文献   
62.
63.
There are many models that require the estimation of a set of ordered parameters. For example, multivariate analysis of variance often is formulated as testing for the equality of the parameters versus an ordered alternative. This problem, referred to as isotonic inference, constrained inference, or isotonic regression, has led to the development of general solutions, not often easy to apply in special models. In this expository paper, we study the special case of a separable convex quadratic programming problem for which the optimality conditions lead to a readily solved linear complementarity problem in the Lagrange multipliers, and subsequently to an equivalent linear programming problem, whose solution can be used to recover the solution of the original isotonic problem. The method can be applied to estimating ordered correlations, ordered binomial probabilities, ordered Poisson parameters, ordered exponential scale parameters, or ordered risk differences.  相似文献   
64.
Asthma patients' health status may be especially sensitive to some types of air pollution, but the evidence on this is mixed. We explore the effects of ground-level ozone on asthma patient's activities, breaking apart the usual aggregated category of leisure into indoor and outdoor activities, and differentiating those by whether the activities were active or inactive. Applying the semiparametric censored estimation method we demonstrate that even though the period over which activities were observed was relatively low in ozone levels, there is a significant impact of ozone on a few activities. The (non-ozone) economic and demographic variables in the model play significant roles in explaining the allocation of time among seven activities, suggesting the suitability of the approach for other household decision-making contexts.  相似文献   
65.
A survey of the extant literature addressing the factors that drive African American municipal employment offers two broad types of explanations: (1) Black political power and (2) institutional. A comparative assessment of the performance of each of these explanations fills a gap in the literature by illuminating the differences of these distinct perspectives when it comes to employment of Blacks in the public sector. Focusing on six Florida cities from 1960 to 2000, this study tests the predictive power of each of these explanations comparatively for four city departments. The findings indicate that the Black political power explanation performs better than the institutional explanation as a predictor of Black employment.  相似文献   
66.
The risky business of insurance pricing   总被引:1,自引:1,他引:0  
The factors influencing insurance pricing decisions are assessed using the ISO product liability ratemaking files for 1980–1984. The mean loss level has a strong positive effect on manual rates and premium rates/exposure. Evidence on a variety of ambiguity measures is more mixed. As a broad generalization, risk ambiguity lowers manual rates, which may reflect exclusion of large loss outliers as being unrepresentative. Risk ambiguity tends to have a positive effect on actual pricing decisions for particular policies, especially bodily injury lines and the interactive risk-ambiguity model.  相似文献   
67.
Squared residual autocorrelations have been found useful in detecting departures from linearity in time series models. This is especially the case with data exhibiting heterogeneity in variances. A rank test is proposed which is much more robust than its parametric counterpart.  相似文献   
68.
This study examines the relationships among personal coping resources, social support, external coping resources, job stressors and job strains in a sample of 110 American Telephone and Telegraph employees undergoing a major organizational restructuring. The study expanded on a model suggested by Ashford (1988) by defining another category of coping resources that employees may draw upon to deal with the stressors and strains which occur during major organizational changes. External coping resources were defined as those which provided employees with a sense of 'vicarious control' in stressful situations. Results indicated that personal coping resources, social support and external coping resources had a direct effect upon job stressor and strain levels. No 'buffering' effect of these coplng resources was found. Hierarchical regression analyses indicated that external coping resources added to the prediction of job stressors and strains even when pertonal coping resources and social support were entered first into the prediction questions.  相似文献   
69.
The author reports on a study of the liquid nitrogen treatment of warts at the Rutgers University Student Health Center. He demonstrates that liquid nitrogen therapy is a safe, effective treatment method, appropriate for use by nurses and other primary providers in a college health setting.  相似文献   
70.
Unions,PAC contributions,and the NAFTA vote   总被引:1,自引:0,他引:1  
Political action committees (PACs), especially those controlled by organized labor and business, have been shown to affect Congressional voting. We explore how PACs influenced the House of Representatives’ vote on the North American Free Trade Agreement (NAFTA). The NAFTA vote is analyzed because organized labor strongly opposed the treaty while business generally supported it and because of the straight-forward voting generated by its fast-track status. Probit analysis of a unique, unpublished data set containing information about PAC and non-PAC contributions to the 1992 House election campaigns demonstrates that Representatives who depended largely on labor PACs tended to oppose NAFTA, while Representatives who derived a large proportion of their campaign contributions from business PACs tended to favor its passage.  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