全文获取类型
收费全文 | 893篇 |
免费 | 34篇 |
国内免费 | 4篇 |
专业分类
管理学 | 75篇 |
人口学 | 1篇 |
丛书文集 | 17篇 |
理论方法论 | 22篇 |
综合类 | 124篇 |
社会学 | 22篇 |
统计学 | 670篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 9篇 |
2021年 | 11篇 |
2020年 | 28篇 |
2019年 | 24篇 |
2018年 | 21篇 |
2017年 | 40篇 |
2016年 | 27篇 |
2015年 | 29篇 |
2014年 | 31篇 |
2013年 | 218篇 |
2012年 | 70篇 |
2011年 | 28篇 |
2010年 | 31篇 |
2009年 | 28篇 |
2008年 | 27篇 |
2007年 | 30篇 |
2006年 | 28篇 |
2005年 | 31篇 |
2004年 | 23篇 |
2003年 | 34篇 |
2002年 | 15篇 |
2001年 | 18篇 |
2000年 | 17篇 |
1999年 | 14篇 |
1998年 | 12篇 |
1997年 | 16篇 |
1996年 | 8篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 8篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有931条查询结果,搜索用时 453 毫秒
791.
Through an investigation of normal curvature functions for influence graphs of a family of perturbed models, we develop the concept of local conditional influence. This concept can be used to study masking and boosting effects in local influence. We identify the situation under which the influence graph of the unperturbed model contains all the information on these effects. The linear regression model is used for illustration and it is shown that the concept developed is consistent with Lawrance's (1995) approach of conditional influence in Cook's distance. 相似文献
792.
This paper proposes a model, which is an extension-of-symmetry model, for square contingency tables with the same nominal row and column classifications. The model states that the absolute values of difference between the conditional probability that an observation will fall in cell (i, j) on condition that it falls in cell (i, j) or (j, i) and the conditional probability that it falls in cell (j, i) on the same condition, are constant for every i≠j. The model describes a structure of asymmetry (not symmetry), and it is applied to the data on a nominal scale. An example is given. 相似文献
793.
The authors introduce the formal notion of an approximately specified nonlinear regression model and investigate sequential design methodologies when the fitted model is possibly of an incorrect parametric form. They present small‐sample simulation studies which indicate that their new designs can be very successful, relative to some common competitors, in reducing mean squared error due to model misspecifi‐cation and to heteroscedastic variation. Their simulations also suggest that standard normal‐theory inference procedures remain approximately valid under the sequential sampling schemes. The methods are illustrated both by simulation and in an example using data from an experiment described in the chemical engineering literature. 相似文献
794.
795.
文章采用主成分分析法分别构造AH股市场综合情绪指数,再运用条件贝塔参数随着投资者情绪和公司特征值变化的两阶段条件资产定价模型进行实证分析,结果表明:加入投资者情绪的条件定价模型,AH股定价的规模效应变得不显著,A股定价的B/M效应显著性明显下降,因此投资者情绪可以帮助定价模型捕捉股票定价异象,但A股定价受投资者情绪影响程度强于H股,不同市场的投资者情绪对资产定价影响程度差异是导致AH股双重上市公司同股不同价的原因之一. 相似文献
796.
This article develops a method for testing the goodness-of-fit of a given parametric autoregressive conditional duration model against unspecified nonparametric alternatives. The test statistics are functions of the residuals corresponding to the quasi maximum likelihood estimate of the given parametric model, and are easy to compute. The limiting distributions of the test statistics are not free from nuisance parameters. Hence, critical values cannot be tabulated for general use. A bootstrap procedure is proposed to implement the tests, and its asymptotic validity is established. The finite sample performances of the proposed tests and several other competing ones in the literature, were compared using a simulation study. The tests proposed in this article performed well consistently throughout, and they were either the best or close to the best. None of the tests performed uniformly the best. The tests are illustrated using an empirical example. 相似文献
797.
798.
In this paper, we obtain a generalized moment identity for the case when the distributions of the random variables are not necessarily purely discrete or absolutely continuous. The proposed identity is useful to find the generator which has been used for the approximation of distributions by Stein's method. Apparently, a new approach is discussed for the approximation of distributions by Stein's method. We bring the characterization based on the relationship between conditional expectations and hazard measure in our unified framework. As an application, a new lower bound to the mean-squared error is obtained and it is compared with Bayesian Cramer–Rao bound. 相似文献
799.
In monitoring clinical trials, the question of futility, or whether the data thus far suggest that the results at the final analysis are unlikely to be statistically successful, is regularly of interest over the course of a study. However, the opposite viewpoint of whether the study is sufficiently demonstrating proof of concept (POC) and should continue is a valuable consideration and ultimately should be addressed with high POC power so that a promising study is not prematurely terminated. Conditional power is often used to assess futility, and this article interconnects the ideas of assessing POC for the purpose of study continuation with conditional power, while highlighting the importance of the POC type I error and the POC type II error for study continuation or not at the interim analysis. Methods for analyzing subgroups motivate the interim analyses to maintain high POC power via an adjusted interim POC significance level criterion for study continuation or testing against an inferiority margin. Furthermore, two versions of conditional power based on the assumed effect size or the observed interim effect size are considered. Graphical displays illustrate the relationship of the POC type II error for premature study termination to the POC type I error for study continuation and the associated conditional power criteria. 相似文献
800.
Vasant P. Bhapkar 《统计学通讯:理论与方法》2013,42(4):945-952
A counter-example shows that the proof of optimality of the marginal likelihood estimating function for parameter of interest, under the conditions assumed in Lloyd (1987), contains a gap and is, thus, invalid. The same comment applies to the generalized version of Lloyd’s Theorem given by Bhapkar and Srinivasan (1993). In the light of known results concerning Fisher information for parameter of interest and partial sufficiency of a suitable statistic, the counter-example reveals a similar gap in the proof of corollary 3.2 of Bhapkar (1991). 相似文献