全文获取类型
收费全文 | 1497篇 |
免费 | 74篇 |
国内免费 | 20篇 |
专业分类
管理学 | 88篇 |
民族学 | 7篇 |
人才学 | 1篇 |
人口学 | 24篇 |
丛书文集 | 112篇 |
理论方法论 | 61篇 |
综合类 | 785篇 |
社会学 | 107篇 |
统计学 | 406篇 |
出版年
2024年 | 2篇 |
2023年 | 16篇 |
2022年 | 15篇 |
2021年 | 26篇 |
2020年 | 28篇 |
2019年 | 72篇 |
2018年 | 53篇 |
2017年 | 42篇 |
2016年 | 49篇 |
2015年 | 46篇 |
2014年 | 79篇 |
2013年 | 175篇 |
2012年 | 90篇 |
2011年 | 78篇 |
2010年 | 73篇 |
2009年 | 93篇 |
2008年 | 112篇 |
2007年 | 91篇 |
2006年 | 59篇 |
2005年 | 65篇 |
2004年 | 63篇 |
2003年 | 57篇 |
2002年 | 51篇 |
2001年 | 44篇 |
2000年 | 34篇 |
1999年 | 12篇 |
1998年 | 6篇 |
1997年 | 13篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
排序方式: 共有1591条查询结果,搜索用时 171 毫秒
81.
In this article we study the problem of classification of three-level multivariate data, where multiple q-variate observations are measured on u-sites and over p-time points, under the assumption of multivariate normality. The new classification rules with certain structured and unstructured mean vectors and covariance structures are very efficient in small sample scenario, when the number of observations is not adequate to estimate the unknown variance–covariance matrix. These classification rules successfully model the correlation structure on successive repeated measurements over time. Computation algorithms for maximum likelihood estimates of the unknown population parameters are presented. Simulation results show that the introduction of sites in the classification rules improves their performance over the existing classification rules without the sites. 相似文献
82.
The use of covariates in block designs is necessary when the covariates cannot be controlled like the blocking factor in the experiment. In this paper, we consider the situation where there is some flexibility for selection in the values of the covariates. The choice of values of the covariates for a given block design attaining minimum variance for estimation of each of the parameters has attracted attention in recent times. Optimum covariate designs in simple set-ups such as completely randomised design (CRD), randomised block design (RBD) and some series of balanced incomplete block design (BIBD) have already been considered. In this paper, optimum covariate designs have been considered for the more complex set-ups of different partially balanced incomplete block (PBIB) designs, which are popular among practitioners. The optimum covariate designs depend much on the methods of construction of the basic PBIB designs. Different combinatorial arrangements and tools such as orthogonal arrays, Hadamard matrices and different kinds of products of matrices viz. Khatri–Rao product, Kronecker product have been conveniently used to construct optimum covariate designs with as many covariates as possible. 相似文献
83.
84.
This paper is concerned with semiparametric discrete kernel estimators when the unknown count distribution can be considered to have a general weighted Poisson form. The estimator is constructed by multiplying the Poisson estimate with a nonparametric discrete kernel-type estimate of the Poisson weight function. Comparisons are then carried out with the ordinary discrete kernel probability mass function estimators. The Poisson weight function is thus a local multiplicative correction factor, and is considered as the uniform measure to detect departures from the equidispersed Poisson distribution. In this way, the effects of dispersion and zero-proportion with respect to the standard Poisson distribution are also minimized. This method of estimation is also applied to the weighted binomial form for the count distribution having a finite support. The proposed estimators, in addition to being simple, easy-to-implement and effective, also outperform the competing nonparametric and parametric estimators in finite-sample situations. Two examples illustrate this new semiparametric estimation. 相似文献
85.
86.
Y. Parmet 《统计学通讯:理论与方法》2017,46(15):7479-7494
There are two types of decompositions: of linear combinations of random variables into contributions of individual variables (sources) and associations between them, and of populations into contributions of their subpopulations. Simultaneous treatment of the two types is called for, which takes into account the correlations between sources within subpopulations and between subpopulation means. The expected values of the subcomponents are derived and their sensitivity to correlations among sources within groups and among source group means is conducted. An example is provided, in which the correlations contribute 20--25% to total variability. This additional information is hidden when decompositions are not simultaneous. 相似文献
87.
T. Palanisamy 《统计学通讯:模拟与计算》2017,46(6):4991-5001
We propose a variational mode decomposition approach to estimate the variance function in a nonparametric heteroscedastic fixed design regression model. A data-driven estimator is constructed by applying variational mode decomposition technique to the difference-based initial estimates. The numerical results show that the proposed estimator performs better than the existing variance estimation procedures in the mean square sense. 相似文献
88.
该文考虑的是具有分布控制的Timoshenko梁系统的精确能控性.用谱分解方法建立了保守系统的正反向能量不等式,证明了在通常的能量空间中该系统是精确能控的. 相似文献
89.
刘易平 《重庆邮电大学学报(社会科学版)》2012,24(3):107-110
中国传统基础教育以私塾为形式,人文性的四书五经为其内容。清末民初,私塾为理性化的班级授课制所取代,这是理性在教育领域的第一次胜利;近十年来,基础教育集中于乡镇以上学校,村小学被拆并,乡镇初中日渐缩减,农村教育资源被抽空,这是理性在教育领域的进一步扩张。理性化带有形式合理而实质不合理的悖论特质。基础教育之理性化带来高效益的同时,也导致文化意识与价值观念越来越淡漠。目前,较为富强的中国社会也越发意识到,文化归宿之于中国人安身立命以及社会的可持续发展的价值所在。克服教育理性化阴影,在于文化的再植入。故而,面对教育理性化,亟待嵌入文化意识,须将本土文化嵌入基础教育之中以避免教育的无根性。 相似文献
90.
Jenny Snowdon Elmarie Kotzé 《Australian and New Zealand Journal of Family Therapy》2012,33(2):142-156
This article is located in the field of custody and day‐to‐day care, with a focus on experiences of mothering where mothers no longer have everyday care of their children. At the time of writing, tens of thousands of mothers live separately from their children in Aotearoa, New Zealand. However, there is a general perception of rarity associated with non‐resident mothers, partly due to their reluctance to speak of loss of custody. In this article, we develop a theoretical discussion around the inside/outside relationships between non‐resident mothers and their children that informs therapeutic practice. We argue that mothers who live apart from their children are situated at the edge or periphery of their children's day‐to‐day lives and experience this as outside the lives of their children. Nevertheless, mothers' stories speak of qualities of (m)othering that have been born of and nurtured by longstanding and long‐term commitment to their children. 相似文献