全文获取类型
收费全文 | 2268篇 |
免费 | 91篇 |
国内免费 | 34篇 |
专业分类
管理学 | 498篇 |
民族学 | 7篇 |
人口学 | 32篇 |
丛书文集 | 112篇 |
理论方法论 | 101篇 |
综合类 | 1050篇 |
社会学 | 112篇 |
统计学 | 481篇 |
出版年
2024年 | 4篇 |
2023年 | 15篇 |
2022年 | 33篇 |
2021年 | 40篇 |
2020年 | 58篇 |
2019年 | 67篇 |
2018年 | 51篇 |
2017年 | 71篇 |
2016年 | 77篇 |
2015年 | 85篇 |
2014年 | 110篇 |
2013年 | 237篇 |
2012年 | 173篇 |
2011年 | 131篇 |
2010年 | 125篇 |
2009年 | 106篇 |
2008年 | 114篇 |
2007年 | 132篇 |
2006年 | 152篇 |
2005年 | 119篇 |
2004年 | 97篇 |
2003年 | 79篇 |
2002年 | 81篇 |
2001年 | 50篇 |
2000年 | 49篇 |
1999年 | 30篇 |
1998年 | 10篇 |
1997年 | 23篇 |
1996年 | 16篇 |
1995年 | 13篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有2393条查询结果,搜索用时 31 毫秒
821.
基于演化博弈的电力竞价市场均衡分析 总被引:2,自引:0,他引:2
基于非对称演化博弈原理,分别时MCP与PAB竞价机制下的电力竞价市场演化情况进行分析,在此基础上,从市场效率的角度对上述演化均衡进行政策分析,分析结果表明:在MCP机制下,选择适当的竞价上下限,可诱导电力竞价市场收敛于市场效率最高的竞价下限;但在PAB机制下,则不一定.最后,对由5个发电商组成的电力竞价市场进行了算例分析. 相似文献
822.
823.
Using a forward selection procedure for selecting the best subset of regression variables involves the calculation of critical values (cutoffs) for an F-ratio at each step of a multistep search process. On dropping the restrictive (unrealistic) assumptions used in previous works, the null distribution of the F-ratio depends on unknown regression parameters for the variables already included in the subset. For the case of known σ, by conditioning the F-ratio on the set of regressors included so far and also on the observed (estimated) values of their regression coefficients, we obtain a forward selection procedure whose stepwise type I error does not depend on the unknown (nuisance) parameters. A numerical example with an orthogonal design matrix illustrates the difference between conditional cutoffs, cutoffs for the centralF-distribution, and cutoffs suggested by Pope and Webster. 相似文献
824.
Volker Abel 《统计学通讯:理论与方法》2013,42(14):1483-1489
Bayesian multistage inspection plans are often used in inadequate cost models. By means of essentially complete classes this point is made, as well as that of fixed and truncated plans. 相似文献
825.
Given N events occurring over time, define an n:t cluster as n consecutive events all contained within an interval of length t. In this paper we derive the expectation, variance and approximate distribution of the number of n:t clusters. The results have applications in epidemiological studies of rare diseases. 相似文献
826.
《随机性模型》2013,29(2):149-171
Abstract When routing dynamically randomly arriving messages, the controller of a high-speed communication network very often gets the information on the congestion state of down stream nodes only after a considerable delay, making that information irrelevant at decision epochs. We consider the situation where jobs arrive according to a Poisson process and must be routed to one of two (parallel) queues with exponential service time distributions (possibly with different means), without knowing the congestion state in one of the queues. However, the (conditional) probability distribution of the state of the unobservable queue can be computed by the router. We derive the joint probability distribution of the congestion states in both queues as a function of the routing policy. This allows us to identify optimal routing schemes for two types of frameworks: global optimization, in which the weighted sum of average queue lengths is minimized, and individual optimization, in which the goal is to minimize the expected delay of individual jobs. 相似文献
827.
Peter Congdon 《统计学通讯:理论与方法》2013,42(11):1933-1953
Composite morbidity indices summarize geographic inequalities in disease, and are used to distribute resources. A spatial latent variable approach is developed for such an index, focusing on lung cancer in 3,141 U.S. counties. The model incorporates multiple indicators (cancer deaths and incidence), but also allows for population risk variables (area socio-economic, environmental, and smoking indicators) that affect lung cancer, and for missingness among indicators or risk variables. Selection of significant causes is illustrated, including nonadaptive and adaptive selection. To reflect geographic clustering in lung cancer, the latent morbidity index is spatially correlated, although the level of correlation is data determined. 相似文献
828.
M. James 《统计学通讯:理论与方法》2013,42(6):561-568
The generalised inverse equations for the canonical correlation problem are derived using a minimum distance principle which-is shown to be equivalent to the usual maximum correlation formulation. 相似文献
829.
Tong An Hsu 《统计学通讯:理论与方法》2013,42(23):2657-2668
Consider k (k >(>)2) Weibull populations. We shall derive a method of constructing optimal selection procedures to select a subset of the k populations containing the best population which control the size of the selected subset and which maximises the minimum probability of making a correct selection. Procedures and results are derived for the case when sample sizes are unequal. Some tables and figures are given at the end of this paper. 相似文献
830.
Tiejun Tong Zeny Feng Julia S. Hilton Hongyu Zhao 《Journal of applied statistics》2013,40(9):1949-1964
Estimating the proportion of true null hypotheses, π0, has attracted much attention in the recent statistical literature. Besides its apparent relevance for a set of specific scientific hypotheses, an accurate estimate of this parameter is key for many multiple testing procedures. Most existing methods for estimating π0 in the literature are motivated from the independence assumption of test statistics, which is often not true in reality. Simulations indicate that most existing estimators in the presence of the dependence among test statistics can be poor, mainly due to the increase of variation in these estimators. In this paper, we propose several data-driven methods for estimating π0 by incorporating the distribution pattern of the observed p-values as a practical approach to address potential dependence among test statistics. Specifically, we use a linear fit to give a data-driven estimate for the proportion of true-null p-values in (λ, 1] over the whole range [0, 1] instead of using the expected proportion at 1?λ. We find that the proposed estimators may substantially decrease the variance of the estimated true null proportion and thus improve the overall performance. 相似文献