全文获取类型
收费全文 | 424篇 |
免费 | 33篇 |
国内免费 | 1篇 |
专业分类
管理学 | 5篇 |
人口学 | 9篇 |
丛书文集 | 7篇 |
理论方法论 | 5篇 |
综合类 | 47篇 |
社会学 | 14篇 |
统计学 | 371篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 8篇 |
2020年 | 14篇 |
2019年 | 27篇 |
2018年 | 23篇 |
2017年 | 33篇 |
2016年 | 21篇 |
2015年 | 23篇 |
2014年 | 17篇 |
2013年 | 86篇 |
2012年 | 40篇 |
2011年 | 20篇 |
2010年 | 15篇 |
2009年 | 14篇 |
2008年 | 11篇 |
2007年 | 9篇 |
2006年 | 11篇 |
2005年 | 10篇 |
2004年 | 14篇 |
2003年 | 12篇 |
2002年 | 6篇 |
2001年 | 11篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1987年 | 1篇 |
排序方式: 共有458条查询结果,搜索用时 15 毫秒
11.
当前职业学校计算机专业课堂教学缺乏活力、缺少灵活性、模式呆板,教学目标、教学情境、课堂提问、教学活动方面都存在有效性缺失。针对这种情况,若提高计算机专业课堂有效性必经采取如下策略:仔细研究学生、做好学情分析,创造性地使用教材,指导学生由"学会"变为"会学",还要创造民主、和谐的课堂教学环境。 相似文献
12.
Motivated by classification issues that arise in marine studies, we propose a latent-class mixture model for the unsupervised classification of incomplete quadrivariate data with two linear and two circular components. The model integrates bivariate circular densities and bivariate skew normal densities to capture the association between toroidal clusters of bivariate circular observations and planar clusters of bivariate linear observations. Maximum-likelihood estimation of the model is facilitated by an expectation maximization (EM) algorithm that treats unknown class membership and missing values as different sources of incomplete information. The model is exploited on hourly observations of wind speed and direction and wave height and direction to identify a number of sea regimes, which represent specific distributional shapes that the data take under environmental latent conditions. 相似文献
13.
Control‐based imputation for sensitivity analyses in informative censoring for recurrent event data 下载免费PDF全文
Fei Gao Guanghan F. Liu Donglin Zeng Lei Xu Bridget Lin Guoqing Diao Gregory Golm Joseph F. Heyse Joseph G. Ibrahim 《Pharmaceutical statistics》2017,16(6):424-432
In clinical trials, missing data commonly arise through nonadherence to the randomized treatment or to study procedure. For trials in which recurrent event endpoints are of interests, conventional analyses using the proportional intensity model or the count model assume that the data are missing at random, which cannot be tested using the observed data alone. Thus, sensitivity analyses are recommended. We implement the control‐based multiple imputation as sensitivity analyses for the recurrent event data. We model the recurrent event using a piecewise exponential proportional intensity model with frailty and sample the parameters from the posterior distribution. We impute the number of events after dropped out and correct the variance estimation using a bootstrap procedure. We apply the method to an application of sitagliptin study. 相似文献
14.
Ridhi Kashyap 《Population studies》2019,73(1):57-78
I examine whether prenatal sex selection has substituted postnatal excess female mortality by analysing the dynamics of child sex ratios between 1980 and 2015 using country-level life table data. I decompose changes in child sex ratios into a ‘fertility’ component attributable to prenatal sex selection and a ‘mortality’ component attributable to sex differentials in postnatal survival. Although reductions in numbers of excess female deaths have accompanied increases in missing female births in all countries experiencing the emergence of prenatal sex selection, relative excess female mortality has persisted in some countries but not others. In South Korea, Armenia, and Azerbaijan, mortality reductions favouring girls accompanied increases in prenatal sex selection. In India, excess female mortality was much higher and largely stable as prenatal sex selection emerged, but slight reductions were seen in the 2000s. In China, although absolute measures showed reductions, relative excess female mortality persisted as prenatal sex selection increased. 相似文献
15.
Business establishment microdata typically are required to satisfy agency-specified edit rules, such as balance equations and linear inequalities. Inevitably some establishments' reported data violate the edit rules. Statistical agencies correct faulty values using a process known as edit-imputation. Business establishment data also must be heavily redacted before being shared with the public; indeed, confidentiality concerns lead many agencies not to share establishment microdata as unrestricted access files. When microdata must be heavily redacted, one approach is to create synthetic data, as done in the U.S. Longitudinal Business Database and the German IAB Establishment Panel. This article presents the first implementation of a fully integrated approach to edit-imputation and data synthesis. We illustrate the approach on data from the U.S. Census of Manufactures and present a variety of evaluations of the utility of the synthetic data. The paper also presents assessments of disclosure risks for several intruder attacks. We find that the synthetic data preserve important distributional features from the post-editing confidential microdata, and have low risks for the various attacks. 相似文献
16.
Yunquan Song Yanji Zhu Xiuli Wang Lu Lin 《Journal of Statistical Computation and Simulation》2019,89(17):3196-3212
Nonresponse is a very common phenomenon in survey sampling. Nonignorable nonresponse – that is, a response mechanism that depends on the values of the variable having nonresponse – is the most difficult type of nonresponse to handle. This article develops a robust estimation approach to estimating equations (EEs) by incorporating the modelling of nonignorably missing data, the generalized method of moments (GMM) method and the imputation of EEs via the observed data rather than the imputed missing values when some responses are subject to nonignorably missingness. Based on a particular semiparametric logistic model for nonignorable missing response, this paper proposes the modified EEs to calculate the conditional expectation under nonignorably missing data. We can apply the GMM to infer the parameters. The advantage of our method is that it replaces the non-parametric kernel-smoothing with a parametric sampling importance resampling (SIR) procedure to avoid nonparametric kernel-smoothing problems with high dimensional covariates. The proposed method is shown to be more robust than some current approaches by the simulations. 相似文献
17.
张红 《太原理工大学学报(社会科学版)》2014,(2):73-76
《西湖梦寻》是明清之际著名文人张岱所著的史料笔记,中华书局、上海古籍出版社均以马兴荣点校本为底本进行了排印。但参照《武林掌故丛编》所收《西湖梦寻》及《续修四库全书》所记录康熙本《西湖梦寻》,发现该点校本中存在文字形近讹误、文字音同讹误、衍文、脱文、标点误用等舛讹之处。 相似文献
18.
《Journal of Statistical Computation and Simulation》2012,82(2):273-289
The weighted kappa coefficient of a binary diagnostic test is a measure of the beyond-chance agreement between the diagnostic test and the gold standard, and is a measure that allows us to assess and compare the performance of binary diagnostic tests. In the presence of partial disease verification, the comparison of the weighted kappa coefficients of two or more binary diagnostic tests cannot be carried out ignoring the individuals with an unknown disease status, since the estimators obtained would be affected by verification bias. In this article, we propose a global hypothesis test based on the chi-square distribution to simultaneously compare the weighted kappa coefficients when in the presence of partial disease verification the missing data mechanism is ignorable. Simulation experiments have been carried out to study the type I error and the power of the global hypothesis test. The results have been applied to the diagnosis of coronary disease. 相似文献
19.
Due to destructiveness of natural disasters, restriction of disaster scenarios and some human causes, missing data usually occur in disaster decision-making problems. In order to estimate missing values of alternatives, this paper focuses on imputing heterogeneous attribute values of disaster based on an improved K nearest neighbor imputation (KNNI) method. Firstly, some definitions of trapezoidal fuzzy numbers (TFNs) are introduced and three types of attributes (i.e. linguistic term sets, intervals and real numbers) are converted to TFNs. Then the correlated degree model is utilized to extract related attributes to form instances that will be used in K nearest neighbor algorithm, and a novel KNNI method merging with correlated degree model is presented. Finally, an illustrative example is given to verify the proposed method and to demonstrate its feasibility and effectiveness. 相似文献
20.
Amy M. Kwon 《统计学通讯:理论与方法》2017,46(14):6959-6966
When data are outcome-dependent non response, pseudo-likelihood yields consistent regression coefficients without specifying the missing data mechanism. However, it is onerous to derive parameter estimators including their standard errors from the regression coefficients under pseudo-likelihood (PL). The present study applies an imputation method to compute the asymptotic standard errors of parameter estimators. The proposed method is simpler than Delta method and it showed similar effect size of the standard errors to bootstrapping in simulation and application studies. 相似文献