全文获取类型
收费全文 | 633篇 |
免费 | 21篇 |
国内免费 | 3篇 |
专业分类
管理学 | 102篇 |
劳动科学 | 1篇 |
民族学 | 2篇 |
人口学 | 6篇 |
丛书文集 | 20篇 |
理论方法论 | 14篇 |
综合类 | 182篇 |
社会学 | 6篇 |
统计学 | 324篇 |
出版年
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 4篇 |
2020年 | 7篇 |
2019年 | 14篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 15篇 |
2015年 | 18篇 |
2014年 | 17篇 |
2013年 | 164篇 |
2012年 | 40篇 |
2011年 | 22篇 |
2010年 | 27篇 |
2009年 | 17篇 |
2008年 | 28篇 |
2007年 | 27篇 |
2006年 | 26篇 |
2005年 | 25篇 |
2004年 | 23篇 |
2003年 | 34篇 |
2002年 | 15篇 |
2001年 | 11篇 |
2000年 | 9篇 |
1999年 | 8篇 |
1998年 | 10篇 |
1997年 | 9篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 7篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有657条查询结果,搜索用时 109 毫秒
1.
Complete and partial diallel cross designs are examined as to their construction and robustness against the loss of a block of observations. A simple generalized inverse is found for the information matrix of the line effects, which allows evaluation of expressions for the variances of the line-effect differences with and without the missing block. A-efficiencies, based on average variances of the elementary contrasts of the line-effects, suggest that these designs are fairly robust. The loss of efficiency is generally less than 10%, but it is shown that specific comparisons might suffer a loss of efficiency of as much as 40%. 相似文献
2.
John D. Emerson David C. Hoaglin Frederick Mosteller 《Statistical Methods and Applications》1993,2(3):269-290
Summary Meta-analyses of sets of clinical trials often combine risk differences from several 2×2 tables according to a random-effects
model. The DerSimonian-Laird random-effects procedure, widely used for estimating the populaton mean risk difference, weights
the risk difference from each primary study inversely proportional to an estimate of its variance (the sum of the between-study
variance and the conditional within-study variance). Because those weights are not independent of the risk differences, however,
the procedure sometimes exhibits bias and unnatural behavior. The present paper proposes a modified weighting scheme that
uses the unconditional within-study variance to avoid this source of bias. The modified procedure has variance closer to that
available from weighting by ideal weights when such weights are known. We studied the modified procedure in extensive simulation
experiments using situations whose parameters resemble those of actual studies in medical research. For comparison we also
included two unbiased procedures, the unweighted mean and a sample-size-weighted mean; their relative variability depends
on the extent of heterogeneity among the primary studies. An example illustrates the application of the procedures to actual
data and the differences among the results.
This research was supported by Grant HS 05936 from the Agency for Health Care Policy and Research to Harvard University. 相似文献
3.
王亚丰 《辽东学院学报(社会科学版)》2002,4(6):27-29
沈阳在高速经济增长的同时 ,工业化的进程加速 ,产业结构发生很大变化。本文将利用 1 996年和 2 0 0 0年两个时点的投入产出表 ,分析沈阳市产业关联和产业结构变动规律和特征。 相似文献
4.
唐开山 《绍兴文理学院学报》2003,23(9):29-32
讨论了两种二路插入排序的方法,给出了算法思想,分析了这些方法的时间复杂度,其平均时间复杂度比直接插入排序法降低了1/2-1/2,说明这些排序方法比直接插入排序法具有较高的排序效率。 相似文献
5.
Rhoda S. Ritter 《Clinical Social Work Journal》2003,31(4):395-406
This paper is concerned with cases in which patients who have been well established in treatment decide to end it prematurely. In examining the issue among my patients who left against my advice, I isolated in some of them a number of common traits, of which the existence of a long-standing idealizing transference was central. Four of these cases are presented, including two in which the resistance was successfully penetrated and two in which it was not and the patient left treatment. The definition of premature termination is seen in the context of that of a complete analysis. 相似文献
6.
To model an hypothesis of double monotone dependence between two ordinal categorical variables A and B usually a set of symmetric odds ratios defined on the joint probability function is subject to linear inequality constraints. Conversely in this paper two sets of asymmetric odds ratios defined, respectively, on the conditional distributions of A given B and on the conditional distributions of B given A are subject to linear inequality constraints. If the joint probabilities are parameterized by a saturated log-linear model, these constraints are nonlinear inequality constraints on the log-linear parameters. The problem here considered is a non-standard one both for the presence of nonlinear inequality constraints and for the fact that the number of these constraints is greater than the number of the parameters of the saturated log-linear model.This work has been supported by the COFIN 2002 project, references 2002133957_002, 2002133957_004. Preliminary findings have been presented at SIS (Società Italiana di Statistica) Annual Meeting, Bari, 2004. 相似文献
7.
WAPI之争的不完全信息博弈实质分析 总被引:1,自引:0,他引:1
WAPI(无线局域网加密标准)是中国针对国外标准存在的安全隐患,自主研发的对国外的主流标准构成强有力的挑战的无线局域网标准。该标准从宣布强制推行到再宣布推迟执行,充分反映了当今中国无线局域网市场上中外标准竞争的实质。基于产业组织理论的市场进入和阻止理论,分析了WAPI之争潜在的“连锁店悖论”性质,揭示了WAPI之争的不完全信息博弈实质,并据此探讨了我国在这场标准竞争中运用政策和策略的合理性。 相似文献
8.
9.
《Journal of Statistical Computation and Simulation》2012,82(6):807-824
This paper develops a test for comparing treatment effects when observations are missing at random for repeated measures data on independent subjects. It is assumed that missingness at any occasion follows a Bernoulli distribution. It is shown that the distribution of the vector of linear rank statistics depends on the unknown parameters of the probability law that governs missingness, which is absent in the existing conditional methods employing rank statistics. This dependence is through the variance–covariance matrix of the vector of linear ranks. The test statistic is a quadratic form in the linear rank statistics when the variance–covariance matrix is estimated. The limiting distribution of the test statistic is derived under the null hypothesis. Several methods of estimating the unknown components of the variance–covariance matrix are considered. The estimate that produces stable empirical Type I error rate while maintaining the highest power among the competing tests is recommended for implementation in practice. Simulation studies are also presented to show the advantage of the proposed test over other rank-based tests that do not account for the randomness in the missing data pattern. Our method is shown to have the highest power while also maintaining near-nominal Type I error rates. Our results clearly illustrate that even for an ignorable missingness mechanism, the randomness in the pattern of missingness cannot be ignored. A real data example is presented to highlight the effectiveness of the proposed method. 相似文献
10.
陈世寅 《中南林业科技大学学报(社会科学版)》2012,6(3):74-77
在环境法律实践的过程中,通过与污染受害者沟通和交流,发现许多问题都是根源于环境立法存在的问题。也就是,环境立法中的单向的立法理念,只注重至上而下的国家力量,这会导致法律与最初目的的偏离,从保护环境利益走向保护部门利益。因此,要寻求新的出路——发展双向融合的立法理念,即注重至上而下的政府主导与至下而上的公众参与有机结合,通过公众有效参与环境立法,发现环境法律实践中的问题,及时反馈到立法领域。从而在有效的互动中完善环境法治。 相似文献