全文获取类型
收费全文 | 167309篇 |
免费 | 4536篇 |
国内免费 | 1830篇 |
专业分类
管理学 | 4026篇 |
劳动科学 | 31篇 |
民族学 | 2551篇 |
人才学 | 25篇 |
人口学 | 2244篇 |
丛书文集 | 22372篇 |
理论方法论 | 7019篇 |
综合类 | 122403篇 |
社会学 | 6976篇 |
统计学 | 6028篇 |
出版年
2024年 | 296篇 |
2023年 | 886篇 |
2022年 | 1247篇 |
2021年 | 1471篇 |
2020年 | 1893篇 |
2019年 | 1866篇 |
2018年 | 1840篇 |
2017年 | 2270篇 |
2016年 | 2426篇 |
2015年 | 3245篇 |
2014年 | 7971篇 |
2013年 | 9895篇 |
2012年 | 9965篇 |
2011年 | 11817篇 |
2010年 | 9603篇 |
2009年 | 9971篇 |
2008年 | 10384篇 |
2007年 | 12975篇 |
2006年 | 12930篇 |
2005年 | 12070篇 |
2004年 | 11347篇 |
2003年 | 11019篇 |
2002年 | 9011篇 |
2001年 | 7531篇 |
2000年 | 4334篇 |
1999年 | 1291篇 |
1998年 | 668篇 |
1997年 | 529篇 |
1996年 | 455篇 |
1995年 | 377篇 |
1994年 | 293篇 |
1993年 | 254篇 |
1992年 | 217篇 |
1991年 | 189篇 |
1990年 | 108篇 |
1989年 | 130篇 |
1988年 | 78篇 |
1987年 | 47篇 |
1986年 | 47篇 |
1985年 | 109篇 |
1984年 | 147篇 |
1983年 | 98篇 |
1982年 | 96篇 |
1981年 | 65篇 |
1980年 | 62篇 |
1979年 | 60篇 |
1978年 | 51篇 |
1977年 | 18篇 |
1976年 | 12篇 |
1975年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
摘 要:国民收入在部门间的分配流量及其比例,是宏观经济研究的重要内容。研究收入分配问题,不能不考虑部门间在收入分配中的相互关系,但我国目前官方只公布收入与部门交叉数据,还缺乏部门与部门交叉流量数据,且有3年的滞后期。本文采用了一种称为“双矩阵RAS法”的方法,首先利用官方公布的2003年收入与部门交叉数据对2005年收入与部门数据进行了测算,进而用“收入转移法”测算了2005年部门与部门交叉流量数据。分析了1997年至2005年我国部门间收入流量状况,总结出近年来我国部门间收入流量变化的六大特征,并提出了相应的建议。 相似文献
992.
摘 要:理论研究表明许多经济变量呈现出非对称的门限自回归(TAR)或动态门限自回归(M-TAR)数据生成机制,因而非对称单位根检验就成为该领域的主要研究方向之一。本文对非对称单位根检验Enders-Granger方法在GARCH(1,1)-正态误差项下的检验水平与检验势作了系统的仿真研究。研究表明:GARCH(1,1)-正态误差项的TAR或M-TAR模型会对该方法的检验水平和检验势产生重要影响。 相似文献
993.
994.
When we want to compare two designs we usually assume the standard linear model with uncorrelated observations. In this paper we use the comparison method proposed by Ghosh & Shen (2006) to compare three level orthogonal arrays with 18, 27 and 36 runs under a possible presence of correlation in observations. 相似文献
995.
Harriet Namata Ziv Shkedy Christel Faes Marc Aerts Geert Molenberghs Heide Theeten Pierre Van Damme Philippe Beutels 《Journal of applied statistics》2007,34(8):923-939
Based on sero-prevalence data of rubella, mumps in the UK and varicella in Belgium, we show how the force of infection, the age-specific rate at which susceptible individuals contract infection, can be estimated using generalized linear mixed models (McCulloch & Searle, 2001). Modelling the dependency of the force of infection on age by penalized splines, which involve fixed and random effects, allows us to use generalized linear mixed models techniques to estimate both the cumulative probability of being infected before a given age and the force of infection. Moreover, these models permit an automatic selection of the smoothing parameter. The smoothness of the estimated force of infection can be influenced by the number of knots and the degree of the penalized spline used. To determine these, a different number of knots and different degrees are used and the results are compared to establish this sensitivity. Simulations with a different number of knots and polynomial spline bases of different degrees suggest - for estimating the force of infection from serological data - the use of a quadratic penalized spline based on about 10 knots. 相似文献
996.
This paper develops a new characterization of NBUC aging property, and investigates its preservation properties both under
monotonic anti-star-shaped transformations and under the non-homogeneous Poisson shock models. 相似文献
997.
This paper developed an exact method of random permutations when testing both interaction and main effects in the two-way
ANOVA model. The method of this paper can be regarded as a much improved model when compared with those of the previous studies
such as Still and White (1981) and ter Braak (1992). We further conducted a simulation experiment in order to check the statistical
performance of the proposed method. The proposed method works relatively well for small sample sizes compare with the existing
methods.
This work was supported by Korea Science and Engineering Foundation Grant (R14-2003-002-0100) 相似文献
998.
In this paper we examine maximum likelihood estimation procedures in multilevel models for two level nesting structures. Usually,
for fixed effects and variance components estimation, level-one error terms and random effects are assumed to be normally
distributed. Nevertheless, in some circumstances this assumption might not be realistic, especially as concerns random effects.
Thus we assume for random effects the family of multivariate exponential power distributions (MEP); subsequently, by means
of Monte Carlo simulation procedures, we study robustness of maximum likelihood estimators under normal assumption when, actually,
random effects are MEP distributed. 相似文献
999.
Let X
1, X
2,... be iid random variables (rv's) with the support on nonnegative integers and let (W
n
, n≥0) denote the corresponding sequence of weak record values. We obtain new characterization of geometric and some other discrete
distributions based on different forms of partial independence of rv's W
n
and W
n+r
—W
n
for some fixed n≥0 and r≥1. We also prove that rv's W
0 and W
n+1
—W
n
have identical distribution if and only if (iff) the underlying distribution is geometric. 相似文献
1000.
The main problem in applying the mean-variance portfolio selection consists of the fact that the first
two moments of the asset returns are unknown. In practice the optimal portfolio weights have to be estimated.
This is usually done by replacing the moments by the classical unbiased sample estimators. We provide a comparison
of the exact and the asymptotic distributions of the estimated portfolio weights as well as a sensitivity
analysis to shifts in the moments of the asset returns. Furthermore we consider several types of shrinkage
estimators for the moments. The corresponding estimators of the portfolio weights are compared with each
other and with the portfolio weights based on the sample estimators of the moments. We show how the uncertainty
about the portfolio weights can be introduced into the performance measurement of trading strategies. The
methodology explains the bad out-of-sample performance of the classical Markowitz procedures. 相似文献