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   117875篇
  免费   3152篇
  国内免费   1271篇
管理学   2635篇
劳动科学   26篇
民族学   1786篇
人才学   9篇
人口学   1567篇
丛书文集   15979篇
理论方法论   5108篇
综合类   85965篇
社会学   3634篇
统计学   5589篇
  2024年   200篇
  2023年   585篇
  2022年   888篇
  2021年   976篇
  2020年   1217篇
  2019年   1165篇
  2018年   1187篇
  2017年   1536篇
  2016年   1596篇
  2015年   2189篇
  2014年   5364篇
  2013年   6737篇
  2012年   6812篇
  2011年   8158篇
  2010年   6694篇
  2009年   6885篇
  2008年   7275篇
  2007年   9201篇
  2006年   9333篇
  2005年   8679篇
  2004年   8310篇
  2003年   8007篇
  2002年   6517篇
  2001年   5438篇
  2000年   3230篇
  1999年   968篇
  1998年   487篇
  1997年   396篇
  1996年   344篇
  1995年   289篇
  1994年   223篇
  1993年   181篇
  1992年   169篇
  1991年   130篇
  1990年   87篇
  1989年   71篇
  1988年   82篇
  1987年   31篇
  1986年   36篇
  1985年   106篇
  1984年   110篇
  1983年   84篇
  1982年   71篇
  1981年   63篇
  1980年   58篇
  1979年   52篇
  1978年   46篇
  1977年   16篇
  1976年   11篇
  1975年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
271.
Whereas period life expectancy constitutes an intuitive indicator of the survival conditions prevailing at a particular period, this paper argues that, given the existence of welfare interdependencies, that widespread indicator is nonetheless an incomplete measure of the longevity achievements relevant for human well-being. The central importance of coexistence for human-beings implies that usual life expectancy measures should be complemented by joint life expectancy indicators, which measure the average coexistence time under particular survival conditions. After a study of the theoretical foundations of ‘single’ and ‘joint’ life expectancy indicators, it is shown that joint life expectancy measures tend to enrich significantly the comparison of longevity achievements across countries and periods. Moreover, the introduction of joint life expectancy indicators—as a complement to conventional life expectancy measures—into multi-variable indexes such as the United Nations’ HDI is also shown to affect international rankings of standards of living to a non negligible extent.
Gregory PonthiereEmail:
  相似文献   
272.
对于整个中国社会而言,农民工阶层的上向社会流动是事关城乡协调发展实现共同富裕、优化社会结构、保持社会稳定、扩大内需拉动经济发展等宏观目标得以实现的重要因素之一。因而我国必须尽快解决农民工阶层"凝固化"倾向所带来的社会问题,令广大的农民工上向社会流动为全社会带来更大的价值。  相似文献   
273.
中国高龄老人生活自理能力纵向动态研究   总被引:4,自引:0,他引:4  
利用"中国老年健康长寿跟踪调查"1998年、2000年、2002年的跟踪数据分析中国高龄老人ADL的变动趋势及其影响因素。个体增长模型结果显示,高龄老人ADL状况随年龄增长出现了明显的下降趋势,ADL个体差异十分显著。个体之间的差异解释了ADL总差异的31.13%。经历三次追踪调查的高龄老人ADL均值较高,状况较好,下降速度较慢;基期具有3-4项残障的高龄老人,未来ADL下降最为迅速;基期ADL水平高的高龄老人,ADL下降较慢。从ADL的个体影响因素来看,对于基期ADL水平影响最大的变量是"年龄"、"疾病状况"以及"居住安排"等,而对观测期ADL变动速度影响最大的变量是"年龄"以及"过去是否经常从事体力劳动"等。  相似文献   
274.
The EM algorithm is a popular method for computing maximum likelihood estimates. One of its drawbacks is that it does not produce standard errors as a by-product. We consider obtaining standard errors by numerical differentiation. Two approaches are considered. The first differentiates the Fisher score vector to yield the Hessian of the log-likelihood. The second differentiates the EM operator and uses an identity that relates its derivative to the Hessian of the log-likelihood. The well-known SEM algorithm uses the second approach. We consider three additional algorithms: one that uses the first approach and two that use the second. We evaluate the complexity and precision of these three and the SEM in algorithm seven examples. The first is a single-parameter example used to give insight. The others are three examples in each of two areas of EM application: Poisson mixture models and the estimation of covariance from incomplete data. The examples show that there are algorithms that are much simpler and more accurate than the SEM algorithm. Hopefully their simplicity will increase the availability of standard error estimates in EM applications. It is shown that, as previously conjectured, a symmetry diagnostic can accurately estimate errors arising from numerical differentiation. Some issues related to the speed of the EM algorithm and algorithms that differentiate the EM operator are identified.  相似文献   
275.
In 1960 Levene suggested a potentially robust test of homogeneity of variance based on an ordinary least squares analysis of variance of the absolute values of mean-based residuals. Levene's test has since been shown to have inflated levels of significance when based on the F-distribution, and tests a hypothesis other than homogeneity of variance when treatments are unequally replicated, but the incorrect formulation is now standard output in several statistical packages. This paper develops a weighted least squares analysis of variance of the absolute values of both mean-based and median-based residuals. It shows how to adjust the residuals so that tests using the F -statistic focus on homogeneity of variance for both balanced and unbalanced designs. It shows how to modify the F -statistics currently produced by statistical packages so that the distribution of the resultant test statistic is closer to an F-distribution than is currently the case. The weighted least squares approach also produces component mean squares that are unbiased irrespective of which variable is used in Levene's test. To complete this aspect of the investigation the paper derives exact second-order moments of the component sums of squares used in the calculation of the mean-based test statistic. It shows that, for large samples, both ordinary and weighted least squares test statistics are equivalent; however they are over-dispersed compared to an F variable.  相似文献   
276.
在牧区生产方面 ,大比例尺草地植被分布图是非常重要的基础资料 ,对于划区轮牧、草场轮刈以及草地权属落实等都是最基础的档案 ,然而大比例尺植被图 ( 1:50 0 0 )的测绘却很少有人探讨 ,本文从生产发展需要出发 ,试用测绘学方法白纸测图技术 ,进行 1:50 0 0植物群落分布图的测绘研究 ,此方法可以概括为草群分类、样地选择、界线勾绘、建立控制网、样地扩展、分板实测、联绘成图等步骤  相似文献   
277.
Pope  Robin 《Theory and Decision》2000,49(3):223-234
Expected utility theory does not directly deal with the utility of chance. It has been suggested in the literature (Samuelson, 1952, Markowitz, 1959) that this can be remedied by an approach which explicitly models the emotional consequences which give rise to the utility of chance. We refer to this as the elaborated outcomes approach. It is argued that the elaborated outcomes approach destroys the possibility of deriving a representation theorem based on the usual axioms of expected utility theory. This is shown with the help of an example due to Markowitz. It turns out that the space of conceivable lotteries over elaborated outcomes is too narrow to permit the application of the axioms. Moreover it is shown that a representation theorem does not hold for the example.  相似文献   
278.
Ivanenko  V.I.  Munier  B. 《Theory and Decision》2000,49(2):127-150
It is shown that the uncertainty connected with a `random in a broad sense' (not necessarily stochastic) event always has some `statistical regularity' (SR) in the form of a family of finite-additive probability distributions. The specific principle of guaranteed result in decision making is introduced. It is shown that observing this principle of guaranteed result leads to determine the one optimality criterion corresponding to a decision system with a given `statistical regularity'.  相似文献   
279.
刘丽文 《求是学刊》2000,(5):99-106
本文认为,《左传》“多叙鬼神之事,预言祸福之期”现象的产生不是偶然的,而是尚未脱离神职的史官,或者说与宗教文化有千丝万缕联系的史官文化在探究天(神)人关系时的必然现象。《左传》既大讲鬼神对人的控制,又渲染道德决定人的归宿,本文通过对这一看似矛盾现象的系统分析认为,《左传》通过对鬼神预言结果的道德阐释,以高超的技巧将看似杂乱无章的神秘预言纳入到了一个“天德合一”的模式中,从而建构了一个天命控制人类历史,道德决定人的命运的完整的天命观体系;这种把天命神学纳入历史道德领域的努力,是《左传》作者为解释春秋战国之际的历史变迁而做的理论准备,这种试图以建构体系的方式阐释天人关系、历史规律的尝试也是值得肯定的。  相似文献   
280.
诗学审美意象论   总被引:1,自引:0,他引:1  
文章梳理了意象从卜筮—礼法—哲学—文学领域的历史生成和语义转换 ,界定了审美意象的词义层面 ,辨析了审美意象与物象、表象、形象的区别 ,从表现手法、感觉功能、物质属性三个逻辑起点 ,划分了诗学审美意象的类型  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