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   2611篇
  免费   74篇
  国内免费   26篇
管理学   303篇
民族学   2篇
人口学   41篇
丛书文集   74篇
理论方法论   131篇
综合类   709篇
社会学   79篇
统计学   1372篇
  2024年   1篇
  2023年   10篇
  2022年   14篇
  2021年   31篇
  2020年   59篇
  2019年   75篇
  2018年   72篇
  2017年   131篇
  2016年   67篇
  2015年   79篇
  2014年   90篇
  2013年   619篇
  2012年   179篇
  2011年   89篇
  2010年   92篇
  2009年   85篇
  2008年   100篇
  2007年   118篇
  2006年   110篇
  2005年   96篇
  2004年   101篇
  2003年   64篇
  2002年   70篇
  2001年   62篇
  2000年   35篇
  1999年   32篇
  1998年   18篇
  1997年   28篇
  1996年   17篇
  1995年   17篇
  1994年   17篇
  1993年   17篇
  1992年   22篇
  1991年   16篇
  1990年   9篇
  1989年   8篇
  1988年   15篇
  1987年   6篇
  1986年   7篇
  1985年   7篇
  1984年   5篇
  1983年   5篇
  1982年   2篇
  1981年   4篇
  1980年   3篇
  1979年   2篇
  1978年   2篇
  1977年   2篇
  1975年   1篇
排序方式: 共有2711条查询结果,搜索用时 171 毫秒
61.
本文概述了当前美国有线电视行业/付费视频行业的局势,以及一些重要问题和面临的挑战,展望了未来的视频市场,概述了一个未来视频/宽带市场的战略愿景,然后回归到政策建议及具体的立法和管制行动。这将帮助我们在最短的、可操作的时间内通向一个开放的、非歧视性的、无处不在的宽带网络。  相似文献   
62.
The literature on sequential estimation problems for negative exponential populations has been reviewed here, We attempt to bring in all the published and unpublished materials known to us in a fairly coherent fashion. Both the concepts and theoretical findings are discussed.  相似文献   
63.
This paper concludes our comprehensive study on point estimation of model parameters of a gamma distribution from a second-order decision theoretic point of view. It should be noted that efficient estimation of gamma model parameters for samples ‘not large’ is a challenging task since the exact sampling distributions of the maximum likelihood estimators and its variants are not known. Estimation of a gamma scale parameter has received less attention from the earlier researchers compared to shape parameter estimation. What we have observed here is that improved estimation of the shape parameter does not necessarily lead to improved scale estimation if a natural moment condition (which is also the maximum likelihood restriction) is satisfied. Therefore, this work deals with the gamma scale parameter estimation as a separate new problem, not as a by-product of the shape parameter estimation, and studies several estimators in terms of second-order risk.  相似文献   
64.
Stein's estimator and some other estimators of the mean of a K-variate normal distribution are known to dominate the maximum likelihood estimator under quadratic loss for K > 3, and are therefore minimax. In this paper it is shown that the minimax property of Stein's rule is preserved with respect to a generalized loss function.  相似文献   
65.
In this paper the generalized compound Rayleigh model, exhibiting flexible hazard rate, is high¬lighted. This makes it attractive for modelling survival times of patients showing characteristics of a random hazard rate. The Bayes estimators are derived for the parameters of this model and some survival time parameters from a right censored sample. This is done with respect to conjugate and discrete priors on the parameters of this model, under the squared error loss function, Varian's asymmetric linear-exponential (linex) loss function and a weighted linex loss function. The future survival time of a patient is estimated under these loss functions. A Monte Carlo simu¬lation procedure is used where closed form expressions of the estimators cannot be obtained. An example illustrates the proposed estimators for this model.  相似文献   
66.
No abstract available for this article.  相似文献   
67.
ABSTRACT

This paper reports a nearly two-year intervention with staff at a major urban pediatric facility. The authors worked as trainers and consultants for two groups–the Emergency Department (ED) and Chronic Care units (CC). Following two days of training about grief and loss, highlighting skill building for work with traumatized and grieving children and parents, the consultants worked to develop teams which could provide a Winnicottian holding environment for staff. The efficacy of this staff training is analyzed and support needs of staff members are identified. Findings include varied willingness to make use of group support. Chronic care participants are more likely to express willingness to engage in on-going support for one another, while ED staff members seem to prefer structured, educational training and episodic support. The holding environment of the processing groups must be adapted to fit the needs of the medical sub-culture.  相似文献   
68.
以往研究认为沉没成本效应的产生与损失厌恶和后悔厌恶相关,但对其相互关系的探讨较少考虑货币性沉没成本和非货币性沉没成本的不同影响.文章选取证券监管者和证券市场投资者作为被试对象,通过有情境因素的调查问卷对损失厌恶、后悔厌恶与沉没成本效应之间的关联性进行验证.实证结果发现,与证券市场投资者相比,证券监管者的损失厌恶倾向要显著更低,而二者的后悔厌恶和沉没成本效应则无显著差异;证券监管者的数据结果表明,后悔厌恶与沉没成本效应之间存在显著的相关性,而损失厌恶与沉没成本效应之间不存在显著的相关性;相比之下,证券市场投资者的数据结果则表明,损失厌恶与沉没成本之间存在显著的相关性,而后悔厌恶与沉没成本之间则不存在显著的相关性.  相似文献   
69.
70.
Oracle Inequalities for Convex Loss Functions with Nonlinear Targets   总被引:1,自引:1,他引:0  
This article considers penalized empirical loss minimization of convex loss functions with unknown target functions. Using the elastic net penalty, of which the Least Absolute Shrinkage and Selection Operator (Lasso) is a special case, we establish a finite sample oracle inequality which bounds the loss of our estimator from above with high probability. If the unknown target is linear, this inequality also provides an upper bound of the estimation error of the estimated parameter vector. Next, we use the non-asymptotic results to show that the excess loss of our estimator is asymptotically of the same order as that of the oracle. If the target is linear, we give sufficient conditions for consistency of the estimated parameter vector. We briefly discuss how a thresholded version of our estimator can be used to perform consistent variable selection. We give two examples of loss functions covered by our framework.  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