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   4349篇
  免费   89篇
  国内免费   17篇
管理学   224篇
劳动科学   1篇
民族学   7篇
人口学   40篇
丛书文集   131篇
理论方法论   32篇
综合类   1295篇
社会学   49篇
统计学   2676篇
  2024年   1篇
  2023年   16篇
  2022年   19篇
  2021年   29篇
  2020年   60篇
  2019年   106篇
  2018年   131篇
  2017年   222篇
  2016年   84篇
  2015年   95篇
  2014年   156篇
  2013年   1108篇
  2012年   317篇
  2011年   143篇
  2010年   154篇
  2009年   124篇
  2008年   156篇
  2007年   155篇
  2006年   147篇
  2005年   139篇
  2004年   124篇
  2003年   100篇
  2002年   81篇
  2001年   97篇
  2000年   100篇
  1999年   81篇
  1998年   64篇
  1997年   59篇
  1996年   72篇
  1995年   59篇
  1994年   40篇
  1993年   31篇
  1992年   38篇
  1991年   12篇
  1990年   29篇
  1989年   17篇
  1988年   21篇
  1987年   3篇
  1986年   4篇
  1985年   11篇
  1984年   9篇
  1983年   9篇
  1982年   7篇
  1981年   3篇
  1980年   6篇
  1979年   6篇
  1978年   5篇
  1977年   1篇
  1976年   1篇
  1975年   3篇
排序方式: 共有4455条查询结果,搜索用时 15 毫秒
31.
构建了血管的三维重建模型 ,并给出了模型的算法及其求解结果 .  相似文献   
32.
组合预测误差信息矩阵研究   总被引:11,自引:0,他引:11  
研究组合预测误差信息矩阵的结构与组合预测方法性质之间的联系,首次提出冗余信息概念,对最优组合预测方法的组合结构进行了研究。  相似文献   
33.
We present an explicit characterization of the joint dependency structure of an n×p matrix normal random matrix such that the p-dimensional sample mean vector is independent of all translation invariant statistics.  相似文献   
34.
Annual concentrations of toxic air contaminants are of primary concern from the perspective of chronic human exposure assessment and risk analysis. Despite recent advances in air quality monitoring technology, resource and technical constraints often impose limitations on the availability of a sufficient number of ambient concentration measurements for performing environmental risk analysis. Therefore, sample size limitations, representativeness of data, and uncertainties in the estimated annual mean concentration must be examined before performing quantitative risk analysis. In this paper, we discuss several factors that need to be considered in designing field-sampling programs for toxic air contaminants and in verifying compliance with environmental regulations. Specifically, we examine the behavior of SO2, TSP, and CO data as surrogates for toxic air contaminants and as examples of point source, area source, and line source-dominated pollutants, respectively, from the standpoint of sampling design. We demonstrate the use of bootstrap resampling method and normal theory in estimating the annual mean concentration and its 95% confidence bounds from limited sampling data, and illustrate the application of operating characteristic (OC) curves to determine optimum sample size and other sampling strategies. We also outline a statistical procedure, based on a one-sided t-test, that utilizes the sampled concentration data for evaluating whether a sampling site is compliance with relevant ambient guideline concentrations for toxic air contaminants.  相似文献   
35.
本文从高等数学对初等数学的渗透,高观点下的初等数学,高等数学对初等数学的直接指导作用三个方面阐述了初等数学与高等数学的融合。  相似文献   
36.
Gini’s nuclear family   总被引:1,自引:0,他引:1  
The purpose of this paper is to justify the use of the Gini coefficient and two close relatives for summarizing the basic information of inequality in distributions of income. To this end we employ a specific transformation of the Lorenz curve, the scaled conditional mean curve, rather than the Lorenz curve as the basic formal representation of inequality in distributions of income. The scaled conditional mean curve is shown to possess several attractive properties as an alternative interpretation of the information content of the Lorenz curve and furthermore proves to yield essential information on polarization in the population. The paper also provides asymptotic distribution results for the empirical scaled conditional mean curve and the related family of empirical measures of inequality.   相似文献   
37.
本文利用矩阵块对角占优的性质,给出矩阵非奇异的一个判定条件  相似文献   
38.
The authors consider Bayesian analysis for continuous‐time Markov chain models based on a conditional reference prior. For such models, inference of the elapsed time between chain observations depends heavily on the rate of decay of the prior as the elapsed time increases. Moreover, improper priors on the elapsed time may lead to improper posterior distributions. In addition, an infinitesimal rate matrix also characterizes this class of models. Experts often have good prior knowledge about the parameters of this matrix. The authors show that the use of a proper prior for the rate matrix parameters together with the conditional reference prior for the elapsed time yields a proper posterior distribution. The authors also demonstrate that, when compared to analyses based on priors previously proposed in the literature, a Bayesian analysis on the elapsed time based on the conditional reference prior possesses better frequentist properties. The type of prior thus represents a better default prior choice for estimation software.  相似文献   
39.
随着科学技术的发展 ,研究和探讨科技翻译的著作不断问世 ,但是目前有些论述科技英汉、汉英翻译的书籍在使用汉语语法术语方面不够正确。该文从词、句子成分和句的角度分析了汉语语法术语误用的情况。  相似文献   
40.
Finding optimal, or at least good, maintenance and repair policies is crucial in reliability engineering. Likewise, describing life phases of human mortality is important when determining social policy or insurance premiums. In these tasks, one searches for distributions to fit data and then makes inferences about the population(s). In the present paper, we focus on bathtub‐type distributions and provide a view of certain problems, methods and solutions, and a few challenges, that can be encountered in reliability engineering, survival analysis, demography and actuarial science.  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