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   1963篇
  免费   66篇
  国内免费   36篇
管理学   308篇
民族学   42篇
人口学   40篇
丛书文集   122篇
理论方法论   135篇
综合类   869篇
社会学   172篇
统计学   377篇
  2024年   3篇
  2023年   18篇
  2022年   20篇
  2021年   25篇
  2020年   50篇
  2019年   46篇
  2018年   54篇
  2017年   68篇
  2016年   61篇
  2015年   65篇
  2014年   89篇
  2013年   246篇
  2012年   127篇
  2011年   93篇
  2010年   97篇
  2009年   98篇
  2008年   104篇
  2007年   110篇
  2006年   91篇
  2005年   104篇
  2004年   104篇
  2003年   92篇
  2002年   58篇
  2001年   57篇
  2000年   41篇
  1999年   25篇
  1998年   20篇
  1997年   23篇
  1996年   9篇
  1995年   11篇
  1994年   7篇
  1993年   10篇
  1992年   9篇
  1991年   6篇
  1990年   6篇
  1989年   3篇
  1988年   1篇
  1987年   2篇
  1985年   2篇
  1984年   4篇
  1983年   2篇
  1982年   1篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
排序方式: 共有2065条查询结果,搜索用时 15 毫秒
31.
分析了股权众筹融资方和投资方的最优策略.依据股权众筹的流程,构建了股权众筹过程中投融资方利益博弈的3阶段模型,并在同时满足融资方与投资方预期收益最大化的条件下,求解了相应的最优化问题并给出了投融资方最优策略的解析式.研究结果表明,在参数满足一定条件时,股权众筹投融资方均存在最优策略,且最优策略受边际收益、项目成功概率、预期回报率等因素的影响.  相似文献   
32.
We provide an exact myopic analysis for an N‐stage serial inventory system with batch ordering, linear ordering costs, and nonstationary demands under a finite planning horizon. We characterize the optimality conditions of the myopic nested batching newsvendor (NBN) policy and the myopic independent batching newsvendor (IBN) policy, which is a single‐stage approximation. We show that echelon reorder levels under the NBN policy are upper bounds of the counterparts under both the optimal policy and the IBN policy. In particular, we find that the IBN policy has bounded deviations from the optimal policy. We further extend our results to systems with martingale model of forecast evolution (MMFE) and advance demand information. Moreover, we provide a recursive computing procedure and optimality conditions for both heuristics which dramatically reduces computational complexity. We also find that the NBN problem under the MMFE faced by one stage has one more dimension for the forecast demand than the one faced by its downstream stage and that the NBN policy is optimal for systems with advance demand information and stationary problem data. Numerical studies demonstrate that the IBN policy outperforms on average the NBN policy over all tested instances when their optimality conditions are violated.  相似文献   
33.
对上市公司的盈余管理进行对比分析,结果表明现行会计准则为上市公司的盈余管理行为提供了一些机会.因此,需要制定会计准则概念框架,完善会计准则制定程序及准则体系,非经常性损益应在利润表中单独披露,会计准则应规范会计选择变更的披露.  相似文献   
34.
35.
ABSTRACT

Malaysia is one of the multi-ethnic, multi-cultural and multi-religious countries in Southeast Asia. Due to the pluralistic nature of Malaysia, it has a political structure based on ethnic politics. The ethnic preferential policies affected most domains of this country. The objective of this article is to examine the origin and background of ethnic politics in Malaysia. Findings of this study indicate that, ethnic politics originated during the British colonial period, it became a tool used by the Barisan Nasional for the legitimacy of regime. Moreover, ethnic politics in Malaysia today is intertwined with religion. Besides, there is the dilemma of the choice between the interest of certain ethnic group and national interests. However, with the opposition coalition Pakatan Harapan won the election in 9th May, UMNO-led BN lost power and interrupted its 61 years control, which leaves us an interesting topic to think about the future of Malaysian ethnic politics.  相似文献   
36.
The smoothness of Tukey depth contours is a regularity condition often encountered in asymptotic theory, among others. This condition ensures that the Tukey depth fully characterizes the underlying multivariate probability distribution. In this paper we demonstrate that this regularity condition is rarely satisfied. It is shown that even well-behaved probability distributions with symmetrical, smooth and (strictly) quasi-concave densities may have non-smooth Tukey depth contours, and that the smoothness behaviour of depth contours is fairly unpredictable.  相似文献   
37.
Remote sensing of the earth with satellites yields datasets that can be massive in size, nonstationary in space, and non‐Gaussian in distribution. To overcome computational challenges, we use the reduced‐rank spatial random effects (SRE) model in a statistical analysis of cloud‐mask data from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on board NASA's Terra satellite. Parameterisations of cloud processes are the biggest source of uncertainty and sensitivity in different climate models’ future projections of Earth's climate. An accurate quantification of the spatial distribution of clouds, as well as a rigorously estimated pixel‐scale clear‐sky‐probability process, is needed to establish reliable estimates of cloud‐distributional changes and trends caused by climate change. Here we give a hierarchical spatial‐statistical modelling approach for a very large spatial dataset of 2.75 million pixels, corresponding to a granule of MODIS cloud‐mask data, and we use spatial change‐of‐Support relationships to estimate cloud fraction at coarser resolutions. Our model is non‐Gaussian; it postulates a hidden process for the clear‐sky probability that makes use of the SRE model, EM‐estimation, and optimal (empirical Bayes) spatial prediction of the clear‐sky‐probability process. Measures of prediction uncertainty are also given.  相似文献   
38.
In this paper, we consider the problem of making statistical inference for a truncated normal distribution under progressive type I interval censoring. We obtain maximum likelihood estimators of unknown parameters using the expectation-maximization algorithm and in sequel, we also compute corresponding midpoint estimates of parameters. Estimation based on the probability plot method is also considered. Asymptotic confidence intervals of unknown parameters are constructed based on the observed Fisher information matrix. We obtain Bayes estimators of parameters with respect to informative and non-informative prior distributions under squared error and linex loss functions. We compute these estimates using the importance sampling procedure. The highest posterior density intervals of unknown parameters are constructed as well. We present a Monte Carlo simulation study to compare the performance of proposed point and interval estimators. Analysis of a real data set is also performed for illustration purposes. Finally, inspection times and optimal censoring plans based on the expected Fisher information matrix are discussed.  相似文献   
39.
市场经济条件下的民族政策问题   总被引:2,自引:0,他引:2  
本文介绍了民族政策的运行环境,着重阐述了市场经济对民族政策的影响及市场经济条件下民族政策的继承与创新。  相似文献   
40.
Sen Gupta (1988) considered a locally most powerful (LMP) test for testing nonzero values of the equicorrelation coefficient of a standard symmetric multivariate normal distribution. This paper constructs analogous tests for the symmetric multivariate normal distribution. It shows that the new test is uniformly most powerful invariant even in the presence of a nuisance parameter, σ2. Further applications of LMP invariant tests to several equicorrelated populations have been considered and an extension to panel data modeling has been suggested.  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