全文获取类型
收费全文 | 23022篇 |
免费 | 306篇 |
国内免费 | 1篇 |
专业分类
管理学 | 3095篇 |
民族学 | 150篇 |
人才学 | 3篇 |
人口学 | 3483篇 |
丛书文集 | 62篇 |
理论方法论 | 1638篇 |
综合类 | 401篇 |
社会学 | 10429篇 |
统计学 | 4068篇 |
出版年
2023年 | 60篇 |
2022年 | 68篇 |
2021年 | 69篇 |
2020年 | 189篇 |
2019年 | 249篇 |
2018年 | 1966篇 |
2017年 | 2083篇 |
2016年 | 1367篇 |
2015年 | 289篇 |
2014年 | 350篇 |
2013年 | 2392篇 |
2012年 | 764篇 |
2011年 | 1473篇 |
2010年 | 1332篇 |
2009年 | 1011篇 |
2008年 | 1074篇 |
2007年 | 1269篇 |
2006年 | 299篇 |
2005年 | 491篇 |
2004年 | 464篇 |
2003年 | 441篇 |
2002年 | 336篇 |
2001年 | 342篇 |
2000年 | 313篇 |
1999年 | 294篇 |
1998年 | 217篇 |
1997年 | 177篇 |
1996年 | 260篇 |
1995年 | 203篇 |
1994年 | 203篇 |
1993年 | 178篇 |
1992年 | 213篇 |
1991年 | 225篇 |
1990年 | 212篇 |
1989年 | 177篇 |
1988年 | 217篇 |
1987年 | 187篇 |
1986年 | 144篇 |
1985年 | 186篇 |
1984年 | 187篇 |
1983年 | 161篇 |
1982年 | 130篇 |
1981年 | 100篇 |
1980年 | 102篇 |
1979年 | 127篇 |
1978年 | 96篇 |
1977年 | 84篇 |
1975年 | 74篇 |
1974年 | 71篇 |
1973年 | 61篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Michael S. Rendall Ryan Admiraal Alessandra DeRose Paola DiGiulio Mark S. Handcock Filomena Racioppi 《Statistical Methods and Applications》2008,17(4):519-539
In non-experimental research, data on the same population process may be collected simultaneously by more than one instrument.
For example, in the present application, two sample surveys and a population birth registration system all collect observations
on first births by age and year, while the two surveys additionally collect information on women’s education. To make maximum
use of the three data sources, the survey data are pooled and the population data introduced as constraints in a logistic
regression equation. Reductions in standard errors about the age and birth-cohort parameters of the regression equation in
the order of three-quarters are obtained by introducing the population data as constraints. A halving of the standard errors
about the education parameters is achieved by pooling observations from the larger survey dataset with those from the smaller
survey. The percentage reduction in the standard errors through imposing population constraints is independent of the total
survey sample size. 相似文献
72.
73.
74.
Banks winners in tournaments are difficult to recognize 总被引:1,自引:0,他引:1
Gerhard J. Woeginger 《Social Choice and Welfare》2003,20(3):523-528
Given a tournament T, a Banks winner of T is the top vertex of any maximal (with respect to inclusion) transitive subtournament of T. In this technical note, we show that the problem of deciding whether some fixed vertex v is a Banks winner for T is NP-complete.
Received: 22 February 2002/Accepted: 20 June 2002
Supported by the START program Y43-MAT of the Austrian Ministry of Science.
I would like to thank two thank the referees for a careful reading of the paper, for helpful remarks, and for many suggestions
how to improve the presentation. 相似文献
75.
S. Vansteelandt E. Goetghebeur 《Journal of the Royal Statistical Society. Series B, Statistical methodology》2003,65(4):817-835
Summary. We estimate cause–effect relationships in empirical research where exposures are not completely controlled, as in observational studies or with patient non-compliance and self-selected treatment switches in randomized clinical trials. Additive and multiplicative structural mean models have proved useful for this but suffer from the classical limitations of linear and log-linear models when accommodating binary data. We propose the generalized structural mean model to overcome these limitations. This is a semiparametric two-stage model which extends the structural mean model to handle non-linear average exposure effects. The first-stage structural model describes the causal effect of received exposure by contrasting the means of observed and potential exposure-free outcomes in exposed subsets of the population. For identification of the structural parameters, a second stage 'nuisance' model is introduced. This takes the form of a classical association model for expected outcomes given observed exposure. Under the model, we derive estimating equations which yield consistent, asymptotically normal and efficient estimators of the structural effects. We examine their robustness to model misspecification and construct robust estimators in the absence of any exposure effect. The double-logistic structural mean model is developed in more detail to estimate the effect of observed exposure on the success of treatment in a randomized controlled blood pressure reduction trial with self-selected non-compliance. 相似文献
76.
Lisa A. Gennetian Greg Duncan Virginia Knox Wanda Vargas Elizabeth Clark‐Kauffman Andrew S. London 《Journal of research on adolescence》2004,14(4):399-423
Using data from 8 random assignment studies and employing meta‐analytic techniques, this article provides systematic evidence that welfare and work policies targeted at low‐income parents have small adverse effects on some school outcomes among adolescents ages 12 to 18 years at follow‐up. These adverse effects were observed mostly for school performance outcomes and occurred in programs that required mothers to work or participate in employment‐related activities and those that encouraged mothers to work voluntarily. The most pronounced negative effects on school outcomes occurred for the group of adolescents who had a younger sibling, possibly because of the increased home and sibling care responsibilities they assumed as their mothers increased their employment. 相似文献
77.
Gayane Novikova 《Transition Studies Review》2004,11(3):213-223
The collapse of the USSR was accompanied by transformation of the South Caucasian latent ethnopolitical conflicts into local wars. Today the situation in the area of the conflicts is “neither war, nor peace”. Three unresolved conflicts of the South Caucasus can be considered as one of the most serious obstacles for establishing a regional security system.The article gives the general characteristics of these conflicts, the trends of their development, taking into account the time factor, and analyzes the behavioral models of the main players – de jure recognized and unrecognized de facto states of the South Caucasus. The basic objective of the main players should be to keep the situation on a level preventing the resumption of the armed conflicts. The attempts of forced resolution of the conflicts are fraught with destabilization of the situation not only in the area of any of these conflicts but in the whole region. 相似文献
78.
Lu Lin 《Statistical Papers》2004,45(4):529-544
The quasi-score function, as defined by Wedderburn (1974) and McCullagh (1983) and so on, is a linear function of observations.
The generalized quasi-score function introduced in this paper is a linear function of some unbiased basis functions, where
the unbiased basis functions may be some linear functions of the observations or not, and can be easily constructed by the
meaning of the parameters such as mean and median and so on. The generalized quasi-likelihood estimate obtained by such a
generalized quasi-score function is consistent and has an asymptotically normal distribution. As a result, the optimum generalized
quasi-score is obtained and a method to construct the optimum unbiased basis function is introduced. In order to construct
the potential function, a conservative generalized estimating function is defined. By conservative, a potential function for
the projected score has many properties of a log-likelihood function. Finally, some examples are given to illustrate the theoretical
results.
This paper is supported by NNSF project (10371059) of China and Youth Teacher Foundation of Nankai University. 相似文献
79.
Starting with its early twentieth century origins, the development of Labor Economics is traced to the present. We describe
an intellectual revolution in which an earlier tra-dition that focused primarily on the institution of the labor union has
been replaced by a perspective that emphasizes the various roles played by labor markets in an eco-nomic system. That earlier
tradition contained very significant ideological elements, whereas its successor deals much more with the world of ideas.
In the course of the debate, which still continues, ideas triumphed over ideology and created modern Labor Economics. 相似文献
80.
Mr. Patrick J. Morrissette M.S.ED. 《Child and Adolescent Social Work Journal》1994,11(3):235-246
This paper proposes a developmental framework for foster parents and outlines four distinct growth stages. Such a framework can be of value to program administrators who are required to assess foster parent development during the crucial matching process. To draw a distinction between each developmental stage, specific instrumental tasks and indicators are outlined. 相似文献