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   533篇
  免费   28篇
  国内免费   8篇
管理学   35篇
民族学   2篇
人口学   4篇
丛书文集   33篇
理论方法论   84篇
综合类   277篇
社会学   15篇
统计学   119篇
  2023年   7篇
  2021年   5篇
  2020年   12篇
  2019年   15篇
  2018年   15篇
  2017年   26篇
  2016年   12篇
  2015年   25篇
  2014年   27篇
  2013年   51篇
  2012年   32篇
  2011年   38篇
  2010年   30篇
  2009年   32篇
  2008年   27篇
  2007年   33篇
  2006年   26篇
  2005年   23篇
  2004年   30篇
  2003年   13篇
  2002年   19篇
  2001年   15篇
  2000年   16篇
  1999年   7篇
  1998年   3篇
  1997年   3篇
  1996年   5篇
  1995年   4篇
  1993年   2篇
  1992年   3篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1985年   1篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1977年   3篇
  1975年   1篇
排序方式: 共有569条查询结果,搜索用时 15 毫秒
11.
The sampling designs dependent on sample moments of auxiliary variables are well known. Lahiri (Bull Int Stat Inst 33:133–140, 1951) considered a sampling design proportionate to a sample mean of an auxiliary variable. Sing and Srivastava (Biometrika 67(1):205–209, 1980) proposed the sampling design proportionate to a sample variance while Wywiał (J Indian Stat Assoc 37:73–87, 1999) a sampling design proportionate to a sample generalized variance of auxiliary variables. Some other sampling designs dependent on moments of an auxiliary variable were considered e.g. in Wywiał (Some contributions to multivariate methods in, survey sampling. Katowice University of Economics, Katowice, 2003a); Stat Transit 4(5):779–798, 2000) where accuracy of some sampling strategies were compared, too.These sampling designs cannot be useful in the case when there are some censored observations of the auxiliary variable. Moreover, they can be much too sensitive to outliers observations. In these cases the sampling design proportionate to the order statistic of an auxiliary variable can be more useful. That is why such an unequal probability sampling design is proposed here. Its particular cases as well as its conditional version are considered, too. The sampling scheme implementing this sampling design is proposed. The inclusion probabilities of the first and second orders were evaluated. The well known Horvitz–Thompson estimator is taken into account. A ratio estimator dependent on an order statistic is constructed. It is similar to the well known ratio estimator based on the population and sample means. Moreover, it is an unbiased estimator of the population mean when the sample is drawn according to the proposed sampling design dependent on the appropriate order statistic.  相似文献   
12.
PKI是基于公钥加密体制的提供公钥加密和数字签名服务的系统或平台,主要由认证中心(CA)、数字证书库、密钥备份及恢复系统、证书撤销处理系统和应用程序接口(API)组成。其中CA是PKI的核心环节,具有证书发放、更新、撤销和验证等功能。PKI技术已在很多领域得到了广泛的应用。  相似文献   
13.
本文给出了在有错检验情况下标准型抽样方案的设计方法,讨论了误检概率p,p′对抽样方案的影响,并给出抽样方案的实际应用。  相似文献   
14.
In late 2009 China launched an innovative, voluntary programme that by 2011 had extended pension coverage to 326.4 million people in the rural sector, including contributors and beneficiaries. It requires one contribution per year and provides a flat‐rate benefit and a contributions‐related benefit through a contributory individual account, with a government guarantee that the benefit will continue for life. The programme encourages participation of persons who do not pay income taxes, and thus have no tax incentive to participate, by providing substantial government subsidies. As a further incentive, old‐age benefits are provided to older parents when all their adult children participate in the contributory programme.  相似文献   
15.
In this paper, a competing risks model is considered under adaptive type-I progressive hybrid censoring scheme (AT-I PHCS). The lifetimes of the latent failure times have Weibull distributions with the same shape parameter. We investigate the maximum likelihood estimation of the parameters. Bayes estimates of the parameters are obtained based on squared error and LINEX loss functions under the assumption of independent gamma priors. We propose to apply Markov Chain Monte Carlo (MCMC) techniques to carry out a Bayesian estimation procedure and in turn calculate the credible intervals. To evaluate the performance of the estimators, a simulation study is carried out.  相似文献   
16.
钢板桩围堰合理的内支撑施工方案对施工安全、工期长短、成本大小均有一定的影响。以阜阳至六安铁路颍河特大桥深水基础超长钢板桩围堰施工实践为例,通过建立钢板桩、内支撑和土层相互作用的三维整体有限元模型,根据封底混凝土施工时机的不同,选择4种施工方案,对超长钢板桩围堰内支撑施工方案进行了探讨。结果表明:封底混凝土施工越早,对围堰结构的整体安全越有利;实际采用的施工方案要根据桥址处工程地质条件,结合实际工程情况,经方案比选和分析论证以后确定。  相似文献   
17.
Chile modernized its social model in two stages characterized by different strategies: developmentalism (1924–73) and the Washington Consensus (1973–2008). In the first stage, the State pursued both social policies of universal coverage and land reform, while also building up the country's economic and institutional infrastructure. After the 1973 military coup, some public services were dismantled and privatized, and the labour movement was suppressed. Since the end of the dictatorship in 1990, resistance to state regulation and an anti‐labour bias have persisted, albeit to a diminishing degree due to advances in democratization and, latterly, the current world economic crisis.  相似文献   
18.
Abstract

The present article deals with the study of association among the elements of a Sudoku square. In this direction, we have defined an association scheme and constructed incomplete Sudoku square designs which are capable of studying four explanatory variables and also happen to be the designs for two-way elimination of heterogeneity. Some series of Partially Balanced Incomplete Block (PBIB) designs have also been obtained.  相似文献   
19.
“新闻事件策划”这个命题自上世纪九十年代中期被提出以后,长期受到广泛争议和关注。在笔者的研究中,以一系列新闻事件策划的理论和实践研究成果为评判标准,主要关注成都市历时打造一年的文化名片“金沙”,以及作为媒体聚焦点的《金沙》音乐剧。在分析“金沙”成功的造势背后,揭示这条“金光闪闪”的文化产业链运作的新思路。  相似文献   
20.
进退格是晚唐郑谷等人为近体诗制定的一种用韵格式。其用韵规则是选择不可通押的邻韵部的字押韵。不能将“东”“冬”、“寒”“删”等视作相通的韵部。正因为用相邻而不相通的韵部的字押韵,才构成了杂体律诗中的进退格。进退格不能用于绝句。该格的产生有先期基础。李贺是最早的作者。  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