全文获取类型
收费全文 | 3616篇 |
免费 | 218篇 |
国内免费 | 9篇 |
专业分类
管理学 | 166篇 |
民族学 | 26篇 |
人口学 | 243篇 |
丛书文集 | 392篇 |
理论方法论 | 211篇 |
综合类 | 1031篇 |
社会学 | 226篇 |
统计学 | 1548篇 |
出版年
2024年 | 2篇 |
2023年 | 18篇 |
2022年 | 14篇 |
2021年 | 27篇 |
2020年 | 74篇 |
2019年 | 89篇 |
2018年 | 93篇 |
2017年 | 64篇 |
2016年 | 66篇 |
2015年 | 78篇 |
2014年 | 187篇 |
2013年 | 473篇 |
2012年 | 128篇 |
2011年 | 178篇 |
2010年 | 92篇 |
2009年 | 178篇 |
2008年 | 151篇 |
2007年 | 193篇 |
2006年 | 96篇 |
2005年 | 68篇 |
2004年 | 109篇 |
2003年 | 160篇 |
2002年 | 220篇 |
2001年 | 194篇 |
2000年 | 150篇 |
1999年 | 53篇 |
1998年 | 64篇 |
1997年 | 61篇 |
1996年 | 31篇 |
1995年 | 47篇 |
1994年 | 45篇 |
1993年 | 3篇 |
1992年 | 9篇 |
1991年 | 10篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 8篇 |
1986年 | 2篇 |
1985年 | 57篇 |
1984年 | 66篇 |
1983年 | 56篇 |
1982年 | 69篇 |
1981年 | 51篇 |
1980年 | 29篇 |
1979年 | 27篇 |
1978年 | 41篇 |
1977年 | 6篇 |
1976年 | 2篇 |
排序方式: 共有3843条查询结果,搜索用时 15 毫秒
41.
In conjunction with TIMET at Waunarlwydd (Swansea, UK) a model has been developed that will optimise the scheduling of various blooms to their eight furnaces so as to minimise the time taken to roll these blooms into the finished mill products. This production scheduling model requires reliable data on times taken for the various furnaces that heat the slabs and blooms to reach the temperatures required for rolling. These times to temperature are stochastic in nature and this paper identifies the distributional form for these times using the generalised F distribution as a modelling framework. The times to temperature were found to be similarly distributed over all furnaces. The identified distributional forms were incorporated into the scheduling model to optimise a particular campaign that was run at TIMET Swansea. Amongst other conclusion it was found that, compared to the actual campaign, the model produced a schedule that reduced the makespan by some 35%. 相似文献
42.
There are many models that require the estimation of a set of ordered parameters. For example, multivariate analysis of variance often is formulated as testing for the equality of the parameters versus an ordered alternative. This problem, referred to as isotonic inference, constrained inference, or isotonic regression, has led to the development of general solutions, not often easy to apply in special models. In this expository paper, we study the special case of a separable convex quadratic programming problem for which the optimality conditions lead to a readily solved linear complementarity problem in the Lagrange multipliers, and subsequently to an equivalent linear programming problem, whose solution can be used to recover the solution of the original isotonic problem. The method can be applied to estimating ordered correlations, ordered binomial probabilities, ordered Poisson parameters, ordered exponential scale parameters, or ordered risk differences. 相似文献
43.
In order to assess the effectiveness of government programs designed to reduce disparities in the health care minority groups receive relative to the majority white population, a proper statistical measure should be used. This article proposes a measure of and its accompanying graph, which is readily interpretable and is not affected by the number of minority subgroups examined. 相似文献
44.
In this paper, we deal with a discrete-time multiserver retrial queue with finite population. Firstly, we study the Markov chain at the epochs immediately after slot boundaries making emphasis on the computation of its steady-state distribution. Then, the main performance measures are investigated. Besides, we simulate the waiting time of a customer in the retrial group under three different queueing policies. Some numerical examples are given to illustrate the analysis. 相似文献
45.
The basic assumption underlying the concept of ranked set sampling is that actual measurement of units is expensive, whereas ranking is cheap. This may not be true in reality in certain cases where ranking may be moderately expensive. In such situations, based on total cost considerations, k-tuple ranked set sampling is known to be a viable alternative, where one selects k units (instead of one) from each ranked set. In this article, we consider estimation of the distribution function based on k-tuple ranked set samples when the cost of selecting and ranking units is not ignorable. We investigate estimation both in the balanced and unbalanced data case. Properties of the estimation procedure in the presence of ranking error are also investigated. Results of simulation studies as well as an application to a real data set are presented to illustrate some of the theoretical findings. 相似文献
46.
Maria Carmen Iglesias-Pérez Jacobo de Uña-Álvarez 《Journal of statistical planning and inference》2008
In this paper we propose a new nonparametric estimator of the conditional distribution function under a semiparametric censorship model. We establish an asymptotic representation of the estimator as a sum of iid random variables, balanced by some kernel weights. This representation is used for obtaining large sample results such as the rate of uniform convergence of the estimator, or its limit distributional law. We prove that the new estimator outperforms the conditional Kaplan–Meier estimator for censored data, in the sense that it exhibits lower asymptotic variance. Illustration through real data analysis is provided. 相似文献
47.
季相林 《重庆邮电学院学报(社会科学版)》2003,15(4):35-38
社会可持续发展不仅是人类追求的目标,也是人类社会发展繁荣至今的根本所在。但我们在强调发展的同时也大力倡导社会公正的实现,只不过是在目前社会主义初级阶段我们更加提倡能够促进社会经济可持续发展的“公正实现”,这种“公正实现”所带来的可持续发展是以效率的提高为前提的。 相似文献
48.
We propose four different GMM estimators that allow almost consistent estimation of the structural parameters of panel probit models with fixed effects for the case of small Tand large N. The moments used are derived for each period from a first order approximation of the mean of the dependent variable conditional on explanatory variables and on the fixed effect. The estimators differ w.r.t. the choice of instruments and whether they use trimming to reduce the bias or not. In a Monte Carlo study, we compare these estimators with pooled probit and conditional logit estimators for different data generating processes. The results show that the proposed estimators outperform these competitors in several situations. 相似文献
49.
工程制图课程体系和教学方法改革的思路与实践 总被引:3,自引:0,他引:3
在阐述工程制图课程重要和特殊地位的基础上 ,概括指出了目前我国工程制图课程改革的三种教学模式 ,并列举了国外部分院校课程改革的实例 ,总结出教改共识。在明确课程改革基本思想的前提下 ,具体提出课程改革的总体思路和实践过程 :整合课程内容 ,形成新的课程体系 ,构建基础平台 ;改革教学手段 ,更新教学方法 ,保证教学质量 ,提高教学效率 相似文献
50.
Michael Weba 《Statistical Papers》2002,43(3):445-452
n possibly different success probabilities p
1, p
2, ..., p
n
is frequently approximated by a Poisson distribution with parameter λ = p
1 + p
2 + ... + p
n
. LeCam's bound p
2
1 + p
2
2 + ... + p
n
2 for the total variation distance between both distributions is particularly useful provided the success probabilities are
small.
The paper presents an improved version of LeCam's bound if a generalized d-dimensional Poisson binomial distribution is to be approximated by a compound Poisson distribution.
Received: May 10, 2000; revised version: January 15, 2001 相似文献