全文获取类型
收费全文 | 494篇 |
免费 | 24篇 |
专业分类
管理学 | 19篇 |
人口学 | 2篇 |
丛书文集 | 11篇 |
理论方法论 | 2篇 |
综合类 | 131篇 |
社会学 | 2篇 |
统计学 | 351篇 |
出版年
2023年 | 6篇 |
2021年 | 8篇 |
2020年 | 13篇 |
2019年 | 17篇 |
2018年 | 12篇 |
2017年 | 24篇 |
2016年 | 18篇 |
2015年 | 25篇 |
2014年 | 12篇 |
2013年 | 126篇 |
2012年 | 41篇 |
2011年 | 14篇 |
2010年 | 15篇 |
2009年 | 12篇 |
2008年 | 14篇 |
2007年 | 12篇 |
2006年 | 11篇 |
2005年 | 18篇 |
2004年 | 14篇 |
2003年 | 9篇 |
2002年 | 8篇 |
2001年 | 10篇 |
2000年 | 11篇 |
1999年 | 5篇 |
1998年 | 12篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有518条查询结果,搜索用时 15 毫秒
101.
Studies on diffusion tensor imaging (DTI) quantify the diffusion of water molecules in a brain voxel using an estimated 3 × 3 symmetric positive definite (p.d.) diffusion tensor matrix. Due to the challenges associated with modelling matrix‐variate responses, the voxel‐level DTI data are usually summarized by univariate quantities, such as fractional anisotropy. This approach leads to evident loss of information. Furthermore, DTI analyses often ignore the spatial association among neighbouring voxels, leading to imprecise estimates. Although the spatial modelling literature is rich, modelling spatially dependent p.d. matrices is challenging. To mitigate these issues, we propose a matrix‐variate Bayesian semiparametric mixture model, where the p.d. matrices are distributed as a mixture of inverse Wishart distributions, with the spatial dependence captured by a Markov model for the mixture component labels. Related Bayesian computing is facilitated by conjugacy results and use of the double Metropolis–Hastings algorithm. Our simulation study shows that the proposed method is more powerful than competing non‐spatial methods. We also apply our method to investigate the effect of cocaine use on brain microstructure. By extending spatial statistics to matrix‐variate data, we contribute to providing a novel and computationally tractable inferential tool for DTI analysis. 相似文献
102.
Anh Nguyen Duc Dominik Heinzmann Claude Berge Marcel Wolbers 《Pharmaceutical statistics》2021,20(2):202-211
One of the challenges in the design of confirmatory trials is to deal with uncertainties regarding the optimal target population for a novel drug. Adaptive enrichment designs (AED) which allow for a data-driven selection of one or more prespecified biomarker subpopulations at an interim analysis have been proposed in this setting but practical case studies of AEDs are still relatively rare. We present the design of an AED with a binary endpoint in the highly dynamic setting of cancer immunotherapy. The trial was initiated as a conventional trial in early triple-negative breast cancer but amended to an AED based on emerging data external to the trial suggesting that PD-L1 status could be a predictive biomarker. Operating characteristics are discussed including the concept of a minimal detectable difference, that is, the smallest observed treatment effect that would lead to a statistically significant result in at least one of the target populations at the interim or the final analysis, respectively, in the setting of AED. 相似文献
103.
本文对独立逆抽样设计下优势比的置信区间的构造进行了研究,包括三个已有的方法,以及本文引入的鞍点逼近方法。通过模拟比较了这四个方法给出的置信区间。模拟结果表明,基于鞍点逼近方法给出的置信区间不比另外三种方法差。并且在一些情况下表现还优于其它三个方法。 相似文献
104.
105.
社会老龄化与住房逆抵押贷款 总被引:4,自引:0,他引:4
包西柱 《重庆建筑大学学报(社会科学版)》2000,(4)
本文从社会老龄化进程给我国社会带来的冲击入手 ,根据我国实际情况分析实行住房逆抵押贷款的必要性和可行性 ,得出我国应该和可以实行住房逆抵押贷款的结论 相似文献
106.
107.
Howard D. Bondell Lexin Li 《Journal of the Royal Statistical Society. Series B, Statistical methodology》2009,71(1):287-299
Summary. The family of inverse regression estimators that was recently proposed by Cook and Ni has proven effective in dimension reduction by transforming the high dimensional predictor vector to its low dimensional projections. We propose a general shrinkage estimation strategy for the entire inverse regression estimation family that is capable of simultaneous dimension reduction and variable selection. We demonstrate that the new estimators achieve consistency in variable selection without requiring any traditional model, meanwhile retaining the root n estimation consistency of the dimension reduction basis. We also show the effectiveness of the new estimators through both simulation and real data analysis. 相似文献
108.
Łukasz Smaga 《统计学通讯:模拟与计算》2017,46(10):7654-7667
The nonparametric and parametric bootstrap methods for multivariate hypothesis testing are developed. They are used to approximate the null distribution of the test statistics proposed by Duchesne and Francq (2015), resulting in bootstrap testing procedures. In the problem of testing for the mean vector of a multivariate distribution, the asymptotic validity of the bootstrap methods is proved. The finite sample performance of the new solutions is demonstrated by means of Monte Carlo simulation studies. They indicate that for small-sample size, the bootstrap tests provide a better finite sample properties than the asymptotic tests considered by Duchesne and Francq (2015). 相似文献
109.
Emilio Gómez–Déniz 《统计学通讯:理论与方法》2017,46(18):9007-9025
In this paper, we assume that the duration of a process has two different intrinsic components or phases which are independent. The first is the time it takes for a trade to be initiated in the market (for example, the time during which agents obtain knowledge about the market in which they are operating and accumulate information, which is coherent with Brownian motion) and the second is the subsequent time required for the trade to develop into a complete duration. Of course, if the first time is zero then the trade is initiated immediately and no initial knowledge is required. If we assume a specific compound Bernoulli distribution for the first time and an inverse Gaussian distribution for the second, the resulting convolution model has a mixture of an inverse Gaussian distribution with its reciprocal, which allows us to specify and test the unobserved heterogeneity in the autoregressive conditional duration (ACD) model.
Our proposals make it possible not only to capture various density shapes of the durations but also easily to accommodate the behaviour of the tail of the distribution and the non monotonic hazard function. The proposed model is easy to fit and characterizes the behaviour of the conditional durations reasonably well in terms of statistical criteria based on point and density forecasts. 相似文献
110.
Ying-Ying Zhang 《统计学通讯:理论与方法》2017,46(14):7125-7133
For the variance parameter of the hierarchical normal and inverse gamma model, we analytically calculate the Bayes rule (estimator) with respect to a prior distribution IG (alpha, beta) under Stein's loss function. This estimator minimizes the posterior expected Stein's loss (PESL). We also analytically calculate the Bayes rule and the PESL under the squared error loss. Finally, the numerical simulations exemplify that the PESLs depend only on alpha and the number of observations. The Bayes rules and PESLs under Stein's loss are unanimously smaller than those under the squared error loss. 相似文献