全文获取类型
收费全文 | 7417篇 |
免费 | 198篇 |
国内免费 | 67篇 |
专业分类
管理学 | 300篇 |
民族学 | 29篇 |
人才学 | 4篇 |
人口学 | 81篇 |
丛书文集 | 652篇 |
理论方法论 | 136篇 |
综合类 | 5025篇 |
社会学 | 186篇 |
统计学 | 1269篇 |
出版年
2024年 | 17篇 |
2023年 | 43篇 |
2022年 | 46篇 |
2021年 | 52篇 |
2020年 | 79篇 |
2019年 | 125篇 |
2018年 | 132篇 |
2017年 | 186篇 |
2016年 | 151篇 |
2015年 | 184篇 |
2014年 | 337篇 |
2013年 | 634篇 |
2012年 | 481篇 |
2011年 | 437篇 |
2010年 | 413篇 |
2009年 | 393篇 |
2008年 | 432篇 |
2007年 | 500篇 |
2006年 | 520篇 |
2005年 | 439篇 |
2004年 | 387篇 |
2003年 | 352篇 |
2002年 | 302篇 |
2001年 | 280篇 |
2000年 | 178篇 |
1999年 | 86篇 |
1998年 | 79篇 |
1997年 | 64篇 |
1996年 | 46篇 |
1995年 | 57篇 |
1994年 | 55篇 |
1993年 | 43篇 |
1992年 | 32篇 |
1991年 | 22篇 |
1990年 | 19篇 |
1989年 | 31篇 |
1988年 | 19篇 |
1987年 | 12篇 |
1986年 | 6篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有7682条查询结果,搜索用时 31 毫秒
981.
本文给出了收入为离散分布的三种计算基尼系数的新方法。利用收入份额法导出了基尼系数协方差算法的离散形式,并因此产生了计算基尼系数的回归系数法。文章重点讨论了基尼系数进行区间估计的两种方法,这些方法也适用于集中度指数,因而它们在测度社会经济领域的不平等中具有着十分广泛的用途。实际应用表明,新算法有效地简化了对基尼系数区间估计的标准差估算。 相似文献
982.
判别企业生命周期的新方法——构面偏差法 总被引:1,自引:0,他引:1
企业生命周期的判别方法存在指标单一、可操作性不强等诸多的问题,成为制约基于生命周期的相关企业管理研究的一个瓶颈。将构面偏差的方法应用到企业生命周期的判别中,详细阐述了基于构面偏差的企业生命周期判别方法的基本原理及应用,并以478个企业数据为例,详细说明了此方法的操作步骤,为基于生命周期的相关研究提供了科学的依据。 相似文献
983.
科技资源配置能力已成为长江地区城市化进程的重要推力。因此,在构建科技资源与城市化耦合系统评价指标体系的基础上,利用耦合协调度模型综合评价长江区域科技资源配置与城市化的交互耦合关系。结果显示:从时间维度看,研究期内长三角科技资源配置能力与城市化进程之间的耦合关系基本上处于磨合阶段,耦合协调度以低度协调耦合状态为主并逐步过渡到中度协调耦合状态;从空间维度看,长三角各城市的科技资源配置与城市化耦合协调度在极度协调耦合、高度协调耦合、中度协调耦合、低度协调耦合四个阶段均有分布,层级分明且大部分城市尚处于低度协调耦合状态。 相似文献
984.
Supersaturated designs are a large class of factorial designs which can be used for screening out the important factors from a large set of potentially active variables. The huge advantage of these designs is that they reduce the experimental cost drastically, but their critical disadvantage is the confounding involved in the statistical analysis. In this article, we propose a method for analyzing data using several types of supersaturated designs. Modifications of widely used information criteria are given and applied to the variable selection procedure for the identification of the active factors. The effectiveness of the proposed method is depicted via simulated experiments and comparisons. 相似文献
985.
Ridge regression solves multicollinearity problems by introducing a biasing parameter that is called ridge parameter; it shrinks the estimates as well as their standard errors in order to reach acceptable results. Many methods are available for estimating a ridge parameter. This article has considered some of these methods and also proposed a combined nonlinear programming model and Kibria method. A simulation study has been made to evaluate the performance of the proposed estimators based on the minimum mean squared error criterion. The simulation study indicates that under certain conditions the proposed estimators outperform the least squares (LS) estimators and other popular existing estimators. Moreover, the new proposed model is applied on dataset that suffers also from the presence of heteroscedastic errors. 相似文献
986.
ABSTRACT We develop Markov chain Monte Carlo algorithms for estimating the parameters of the short-term interest rate model. Using Monte Carlo experiments we compare the Bayes estimators with the maximum likelihood and generalized method of moments estimators. We estimate the model using the Japanese overnight call rate data. 相似文献
987.
Omar Eidous 《统计学通讯:理论与方法》2013,42(7):1211-1221
This paper introduces an appealing semiparametric model for estimating wildlife abundance based on line transect data. The proposed method requires the existence of a parametric model and then improves the estimator using a kernel method. Properties of the resultant estimator are derived and an expression for the asymptotic mean square error (AMSE) of the estimator is given. Minimization of the AMSE leads to an explicit formula for an optimal choice of the smoothing parameter. Small-sample properties of the proposed estimator using the parametric half-normal model are investigated and compared with the classical kernel estimator using both simulations and real data. Numerical results show that improvements over the classical kernel estimator often can be realized even when the true density is far from the half-normal model. 相似文献
988.
The existing process capability indices (PCI's) assume that the distribution of the process being investigated is normal. For non-normal distributions, PCI's become unreliable in that PCI's may indicate the process is capable when in fact it is not. In this paper, we propose a new index which can be applied to any distribution. The proposed indexCf:, is directly related to the probability of non-conformance of the process. For a given random sample, the estimation of Cf boils down to estimating non-parametrically the tail probabilities of an unknown distribution. The approach discussed in this paper is based on the works by Pickands (1975) and Smith (1987). We also discuss the construction of bootstrap confidence intervals of Cf: based on the so-called accelerated bias correction method (BC a:). Several simulations are carried out to demonstrate the flexibility and applicability of Cf:. Two real life data sets are analyzed using the proposed index. 相似文献
989.
A. Narayanan 《统计学通讯:模拟与计算》2013,42(2-3):647-666
A numerically feasible algorithm is proposed for maximum likelihood estimation of the parameters of the Dirichlet distribution. The performance of the proposed method is compared with the method of moments using bias ratio and squared errors by Monte Carlo simulation. For these criteria, it is found that even in small samples maximum likelihood estimation has advantages over the method of moments. 相似文献
990.
An envelope-rejection method is used to generate random variates from the Watson distribution. The method is compact and is competitive with, if not superior to, the existing sampling algorithms. For the girdle form of the Watson distribution, a faster algorithm is proposed. As a result, Johnson's sampling algorithm for the Bingham distribution is improved. 相似文献