首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   35篇
  免费   1篇
管理学   3篇
人口学   2篇
丛书文集   1篇
理论方法论   1篇
社会学   13篇
统计学   16篇
  2020年   1篇
  2019年   2篇
  2017年   2篇
  2016年   3篇
  2014年   1篇
  2013年   10篇
  2010年   2篇
  2006年   4篇
  2004年   2篇
  2003年   1篇
  2001年   1篇
  1998年   1篇
  1997年   2篇
  1996年   1篇
  1995年   1篇
  1990年   1篇
  1983年   1篇
排序方式: 共有36条查询结果,搜索用时 484 毫秒
1.
Point-light and full-view short video clips of female walkers were displayed on a CRT monitor and male students rated the likelihood of selecting a walker for various advances. Relationships between the ratings, the walkers’ self-reported frequencies of being approached, gait cues, and self-rated personality traits were examined. In the point-light condition, raters selected slow walkers with a short stride length and personality traits implying vulnerability as targets for inappropriate touching. In the full-view condition, the raters selected fashionably groomed or physically attractive walkers as sexual advance targets. These criteria corresponded partially with reported occurrences of advances. Awkward movement impression was suggested as a kinematic gait quality influencing sexual advance target choice.  相似文献   
2.
In recent years, immunological science has evolved, and cancer vaccines are now approved and available for treating existing cancers. Because cancer vaccines require time to elicit an immune response, a delayed treatment effect is expected and is actually observed in drug approval studies. Accordingly, we propose the evaluation of survival endpoints by weighted log‐rank tests with the Fleming–Harrington class of weights. We consider group sequential monitoring, which allows early efficacy stopping, and determine a semiparametric information fraction for the Fleming–Harrington family of weights, which is necessary for the error spending function. Moreover, we give a flexible survival model in cancer vaccine studies that considers not only the delayed treatment effect but also the long‐term survivors. In a Monte Carlo simulation study, we illustrate that when the primary analysis is a weighted log‐rank test emphasizing the late differences, the proposed information fraction can be a useful alternative to the surrogate information fraction, which is proportional to the number of events. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
3.
In split-plot experiments, estimation of unknown parameters by generalized least squares (GLS), as opposed to ordinary least squares (OLS), is required, owing to the existence of whole- and subplot errors. However, estimating the error variances is often necessary for GLS. Restricted maximum likelihood (REML) is an established method for estimating the error variances, and its benefits have been highlighted in many previous studies. This article proposes a new two-step residual-based approach for estimating error variances. Results of numerical simulations indicate that the proposed method performs sufficiently well to be considered as a suitable alternative to REML.  相似文献   
4.
Many clinical research studies evaluate a time‐to‐event outcome, illustrate survival functions, and conventionally report estimated hazard ratios to express the magnitude of the treatment effect when comparing between groups. However, it may not be straightforward to interpret the hazard ratio clinically and statistically when the proportional hazards assumption is invalid. In some recent papers published in clinical journals, the use of restricted mean survival time (RMST) or τ ‐year mean survival time is discussed as one of the alternative summary measures for the time‐to‐event outcome. The RMST is defined as the expected value of time to event limited to a specific time point corresponding to the area under the survival curve up to the specific time point. This article summarizes the necessary information to conduct statistical analysis using the RMST, including the definition and statistical properties of the RMST, adjusted analysis methods, sample size calculation, information fraction for the RMST difference, and clinical and statistical meaning and interpretation. Additionally, we discuss how to set the specific time point to define the RMST from two main points of view. We also provide developed SAS codes to determine the sample size required to detect an expected RMST difference with appropriate power and reconstruct individual survival data to estimate an RMST reference value from a reported survival curve.  相似文献   
5.
6.
There exist many studies which treat the inequality and/or interval constraints on coefficients in the homoscedastic linear regression model. However, the sampling performance of the inequality constrained estimators in the heteroscedastic linear model has not been examined. This paper considers the inequality constrained estimators in the heteroscedastic linear regression model and derives their risks under a quadratic loss function. Furthermore, using the inequality constrained estimators, we introduce a pre-test estimator which might be employed after the test for homoscedasticity and derive its risk. In addition, the risk performance of these estimators is evaluated numerically.  相似文献   
7.
When the error terms are autocorrelated, the conventional t-tests for individual regression coefficients mislead us to over-rejection of the null hypothesis. We examine, by Monte Carlo experiments, the small sample properties of the unrestricted estimator of ρ and of the estimator of ρ restricted by the null hypothesis. We compare the small sample properties of the Wald, likelihood ratio and Lagrange multiplier test statistics for individual regression coefficients. It is shown that when the null hypothesis is true, the unrestricted estimator of ρ is biased. It is also shown that the Lagrange multiplier test using the maximum likelihood estimator of ρ performs better than the Wald and likelihood ratio tests.  相似文献   
8.
Obesity in middle-aged humans is a risk factor for many age-related diseases and decreases life expectancy by about 7 years, which is roughly comparable to the combined effect of all cardiovascular disease and cancer on life span. The prevalence of obesity increases up until late middle age and decreases thereafter. Mechanisms that lead to increased obesity with age are not yet well understood, but current evidence implicates impairments in hypothalamic function, especially impairments in the ability of hypothalamic pro-opiomelanocortin neurons to sense nutritional signals. The rapid increase in the prevalence of obesity at all ages in the past decade suggests that, in the next two or three decades, diseases associated with obesity, especially diabetes, will begin to rise rapidly. Indeed, these trends suggest that for the first time in modern history, the life expectancy of people in developed societies will begin to decrease, unless the rapid increase in the prevalence of obesity can be reversed.  相似文献   
9.
价值本身的阐明,在马克思那里是以与价值实体论相混合的形式而展开的,后来的多数马克思学派也继承了这一缺陷。与此相对,作为有别于眼下价值实体论而阐明价值本身的性质的尝试,是日本的两位研究者即宇野弘藏和广松涉的研究。宇野认为:论证劳动价值说(及剩余价值论)即,《资本论》应该不是开头,而是第三篇绝对剩余价值的生产之后才展开价值实体论,第一篇、第二篇则是与作为流通形式论(商品、货币、资本这种价值本身的存在方式的分析)。而广松认为:价值不是单以物理的存在为出发点,而是主体间性地形成的既不是主观的判断也不是客观的实在的东西。  相似文献   
10.
This paper proposes a new treatment for electrical insulation degradation. Some types of insulation which have been used under various circumstances are considered to degrade at various rates in accordance with their stress circumstances. The cross-linked polyethylene (XLPE) insulated cables inspected by major Japanese electric companies clearly indicate such phenomena. By assuming that the inspected specimen is sampled from one of the clustered groups, a mixed degradation model can be constructed. Since the degradation of the insulation under common circumstances is considered to follow a Weibull distribution, a mixture model and a Weibull power law can be combined. This is called The mixture Weibull power law model. By using the maximum likelihood estimation for the newly proposed model to Japanese 22 and 33kV insulation class cables, they are clustered into a certain number of groups by using the AIC and the generalized likelihood ratio test method. The reliability of the cables at specified years are assessed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号