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   1804篇
  免费   49篇
  国内免费   7篇
管理学   124篇
民族学   2篇
人口学   34篇
丛书文集   14篇
理论方法论   22篇
综合类   333篇
社会学   40篇
统计学   1291篇
  2024年   1篇
  2023年   7篇
  2022年   9篇
  2021年   11篇
  2020年   29篇
  2019年   48篇
  2018年   58篇
  2017年   93篇
  2016年   53篇
  2015年   58篇
  2014年   75篇
  2013年   552篇
  2012年   159篇
  2011年   49篇
  2010年   62篇
  2009年   48篇
  2008年   69篇
  2007年   58篇
  2006年   50篇
  2005年   52篇
  2004年   27篇
  2003年   33篇
  2002年   32篇
  2001年   28篇
  2000年   28篇
  1999年   26篇
  1998年   19篇
  1997年   19篇
  1996年   15篇
  1995年   9篇
  1994年   5篇
  1993年   6篇
  1992年   10篇
  1991年   5篇
  1990年   9篇
  1989年   6篇
  1988年   9篇
  1987年   3篇
  1986年   5篇
  1985年   4篇
  1984年   3篇
  1983年   6篇
  1981年   3篇
  1980年   2篇
  1979年   3篇
  1978年   1篇
  1977年   3篇
排序方式: 共有1860条查询结果,搜索用时 31 毫秒
1.
It is uncertain whether Latin America and Caribbean (LAC) countries are approaching a single mortality regime. Over the last three decades, LAC has experienced major public health interventions and the highest number of homicides in the world. However, these interventions and homicide rates are not evenly shared across countries. This study documents trends in life expectancy and lifespan variability for 20 LAC countries, 2000–14. By extending a previous method, we decompose differences in lifespan variability between LAC and a developed world benchmark into cause-specific effects. For both sexes, dispersion of amenable diseases through the age span makes the largest contribution to the gap between LAC and the benchmark. Additionally, for males, the concentration of homicides, accidents, and suicides in mid-life further impedes mortality convergence. Great disparity exists in the region: while some countries are rapidly approaching the developed regime, others remain far behind and suffer a clear disadvantage in population health.  相似文献   
2.
For the unbalanced one-way random effects model with heterogeneous error variances, we propose the non-informative priors for the between-group variance and develop the first- and second-order matching priors. It turns out that the second-order matching priors do not exist and the reference prior and Jeffreys prior do not satisfy a first-order matching criterion. We also show that the first-order matching prior meets the frequentist target coverage probabilities much better than the Jeffreys prior and reference prior through simulation study, and the Bayesian credible intervals based on the matching prior and reference prior give shorter intervals than the existing confidence intervals by examples.  相似文献   
3.
In this paper, the quantile-based flattened logistic distribution has been studied. Some classical and quantile-based properties of the distribution have been obtained. Closed form expressions of L-moments, L-moment ratios and expectation of order statistics of the distribution have been obtained. A quantile-based analysis concerning the method of matching L-moments estimation is employed to estimate the parameters of the proposed model. We further derive the asymptotic variance–covariance matrix of the matching L-Moments estimators of the proposed model. Finally, we apply the proposed model to simulated as well as two real life datasets and compare the fit with the logistic distribution.  相似文献   
4.
Book Reviews     
Books reviewed:
M Hollander and D Wolfe, Nonparametric Statistical Methods
T Leonard and J.S.J Hsu, Bayesian Methods  相似文献   
5.
着重论述了新形势下高校思想教育工作者应该关注的两个重要方面。其一为加强学习提高自身素质 ,适应时代要求 ,其二为在具体学生工作中应当把握的几个重要方面 ,包括工作思路、道德教育、价值取向 ,以及实践教育、心理素质教育、创新教育等。学习与育人 ,构成了思想工作者提高工作成效的两个基本方面  相似文献   
6.
数字水印技术是在数字作品中嵌入不明显的记号。该文分析了印刷品制作中包含数模-模数转换过程的特性,与数字水印技术相结合,将纯数字域的防伪手段应用到模拟领域中的印刷品上。将印刷品扫描打印过程作为失真信道进行建模分析,并在算法中加入预失真;比较了数字水印各算法,结合印刷品的特性采用并改进特征值分解的方法,嵌入和检测有意义水印,通过该水印对二次扫描打印印刷品脆弱不可检测,来达到防伪的要求。该算法相对于空域算法和其他变换域算法有复杂度低、检测准确度高的优势。  相似文献   
7.
高速SDRAM控制器设计的FPGA实现   总被引:1,自引:0,他引:1  
同步动态存储器(SDRAM)控制器通常用有限状态机实现,对于一般的设计方法,由于状态数量多,状态转换通常伴随大的组合逻辑而影响运行速度,因此,SDRAM控制器的速度限制了SDRAM存储器的访问速度。该文从结构优化入手来优化方法,利用状态机分解的思想将大型SDRAM控制状态机用若干小的子状态机实现,达到简化逻辑的目的,不仅提高了速度还节省了资源,对该类大型SDRAM控制器的实现有一定参考意义。  相似文献   
8.
MODEL-ASSISTED HIGHER-ORDER CALIBRATION OF ESTIMATORS OF VARIANCE   总被引:1,自引:0,他引:1  
In survey sampling, interest often centres on inference for the population total using information about an auxiliary variable. The variance of the estimator used plays a key role in such inference. This study develops a new set of higher‐order constraints for the calibration of estimators of variance for various estimators of the population total. The proposed strategy requires an appropriate model for describing the relationship between the response and auxiliary variable, and the variance of the auxiliary variable. It is therefore referred to as a model‐assisted approach. Several new estimators of variance, including the higher‐order calibration estimators of the variance of the ratio and regression estimators suggested by Singh, Horn & Yu and Sitter & Wu are special cases of the proposed technique. The paper presents and discusses the results of an empirical study to compare the performance of the proposed estimators and existing counterparts.  相似文献   
9.
在我国由计划经济向市场经济的体制转轨过程中,货币政策和财政政策已成为我国宏观经济调节的主要手段,在我国的经济发展中发挥了重要作用。但货币政策和财政政策是各自独立的政策体系,由于作用的方式和条件有较大区别,其效果也有较大不同,文章试图应用脉冲响应函数和方差分解方法,对改革开放以来我国货币政策和财政政策的效果进行实证比较研究,并得出有关结论,为我国的宏观调控政策提供理论分析和实证检验的依据。  相似文献   
10.
Not having a variance estimator is a seriously weak point of a sampling design from a practical perspective. This paper provides unbiased variance estimators for several sampling designs based on inverse sampling, both with and without an adaptive component. It proposes a new design, which is called the general inverse sampling design, that avoids sampling an infeasibly large number of units. The paper provide estimators for this design as well as its adaptive modification. A simple artificial example is used to demonstrate the computations. The adaptive and non‐adaptive designs are compared using simulations based on real data sets. The results indicate that, for appropriate populations, the adaptive version can have a substantial variance reduction compared with the non‐adaptive version. Also, adaptive general inverse sampling with a limitation on the initial sample size has a greater variance reduction than without the limitation.  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