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   5091篇
  免费   157篇
管理学   680篇
民族学   24篇
人口学   524篇
丛书文集   20篇
教育普及   1篇
理论方法论   488篇
综合类   59篇
社会学   2389篇
统计学   1063篇
  2023年   32篇
  2021年   50篇
  2020年   89篇
  2019年   117篇
  2018年   128篇
  2017年   194篇
  2016年   140篇
  2015年   82篇
  2014年   133篇
  2013年   783篇
  2012年   161篇
  2011年   145篇
  2010年   124篇
  2009年   110篇
  2008年   137篇
  2007年   127篇
  2006年   148篇
  2005年   112篇
  2004年   112篇
  2003年   76篇
  2002年   98篇
  2001年   131篇
  2000年   122篇
  1999年   132篇
  1998年   101篇
  1997年   86篇
  1996年   93篇
  1995年   68篇
  1994年   61篇
  1993年   87篇
  1992年   89篇
  1991年   97篇
  1990年   78篇
  1989年   78篇
  1988年   61篇
  1987年   68篇
  1986年   62篇
  1985年   75篇
  1984年   66篇
  1983年   69篇
  1982年   44篇
  1981年   40篇
  1980年   37篇
  1979年   47篇
  1978年   38篇
  1977年   33篇
  1976年   34篇
  1975年   32篇
  1974年   40篇
  1973年   29篇
排序方式: 共有5248条查询结果,搜索用时 718 毫秒
481.
482.
483.
近来关于闭环供应链网络的文献中提出了两个重要问题:(1)如何制定平衡环境和经济效益的优化方案;(2)如何深刻理解二者间的效益背反关系。本文认为,针对环境和经济闭的效益边界及其背反关系进行全面探索,可以有效解决环境保护和经济发展中的效益平衡问题。为了解决求解效益边界的多变量问题,本文设计了一个针对目标函数中的数值进行指数计算的生态效益算法,并在德国电子电气设备闭环供应链设计中进行了实证研究。  相似文献   
484.
The Zero Inflated Power Series Distribution (ZIPSD) contains two parameters. The first parameter indicates inflation of zero and the other parameter is that of the Power Series distribution. We provide three asymptotic tests for testing the parameter of Power Series distribution, using an unconditional (standard) likelihood approach, a conditional likelihood approach and a test based on sample mean, respectively. The performance of these three tests has been studied for Zero Inflated Poisson Distribution (ZIPD). Asymptotic Confidence Intervals for the parameter are also provided.  相似文献   
485.
We establish weak and strong posterior consistency of Gaussian process priors studied by Lenk [1988. The logistic normal distribution for Bayesian, nonparametric, predictive densities. J. Amer. Statist. Assoc. 83 (402), 509–516] for density estimation. Weak consistency is related to the support of a Gaussian process in the sup-norm topology which is explicitly identified for many covariance kernels. In fact we show that this support is the space of all continuous functions when the usual covariance kernels are chosen and an appropriate prior is used on the smoothing parameters of the covariance kernel. We then show that a large class of Gaussian process priors achieve weak as well as strong posterior consistency (under some regularity conditions) at true densities that are either continuous or piecewise continuous.  相似文献   
486.
487.
Summary.  We propose a mixture of binomial and beta–binomial distributions for estimating the size of closed populations. The new mixture model is applied to several real capture–recapture data sets and is shown to provide a convenient, objective framework for model selection. The new model is compared with three alternative models in a simulation study, and the results shed light on the general performance of models in this area. The new model provides a robust flexible analysis, which automatically deals with small capture probabilities.  相似文献   
488.
Given observations on an m × n lattice, approximate maximum likelihood estimates are derived for a family of models including direct covariance, spatial moving average, conditional autoregressive and simultaneous autoregressive models. The approach involves expressing the (approximate) covariance matrix of the observed variables in terms of a linear combination of neighbour relationship matrices, raised to a power. The structure is such that the eigenvectors of the covariance matrix are independent of the parameters of interest. This result leads to a simple Fisher scoring type algorithm for estimating the parameters. The ideas are illustrated by fitting models to some remotely sensed data.  相似文献   
489.
A common problem in sociology, psychology, biology, geography, and management science is the comparison of dyadic relational structures (i.e., graphs). Where these structures are formed on a common set of elements, a natural question that arises is whether there is a tendency for elements that are strongly connected in one set of structures to be more—or less—strongly connected within another set. We may ask, for instance, whether there is a correspondence between golf games and business deals, trade and warfare, or spatial proximity and genetic similarity. In each case, the data for such comparisons may be continuous or discrete, and multiple relations may be involved simultaneously (e.g., when comparing multiple measures of international trade volume with multiple types of political interactions). We propose here an exponential family of permutation models that is suitable for inferring the direction and strength of association among dyadic relational structures. A linear-time algorithm is shown for MCMC simulation of model draws, as is the use of simulated draws for maximum likelihood estimation (MCMC-MLE) and/or estimation of Monte Carlo standard errors. We also provide an easily performed maximum pseudo-likelihood estimation procedure for the permutation model family, which provides a reasonable means of generating seed models for the MCMC-MLE procedure. Use of the modeling framework is demonstrated via an application involving relationships among managers in a high-tech firm.  相似文献   
490.
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