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   348篇
  免费   20篇
管理学   28篇
人口学   12篇
丛书文集   4篇
理论方法论   4篇
综合类   35篇
社会学   10篇
统计学   275篇
  2023年   3篇
  2022年   5篇
  2021年   7篇
  2020年   6篇
  2019年   11篇
  2018年   12篇
  2017年   23篇
  2016年   8篇
  2015年   19篇
  2014年   15篇
  2013年   76篇
  2012年   42篇
  2011年   16篇
  2010年   11篇
  2009年   14篇
  2008年   14篇
  2007年   12篇
  2006年   8篇
  2005年   6篇
  2004年   7篇
  2003年   7篇
  2002年   5篇
  2001年   2篇
  2000年   3篇
  1999年   4篇
  1998年   4篇
  1997年   4篇
  1996年   2篇
  1995年   1篇
  1994年   3篇
  1993年   1篇
  1991年   1篇
  1990年   3篇
  1989年   2篇
  1986年   1篇
  1985年   2篇
  1983年   1篇
  1982年   1篇
  1981年   4篇
  1980年   1篇
  1978年   1篇
排序方式: 共有368条查询结果,搜索用时 0 毫秒
351.
ABSTRACT

In the past, a tolerance interval was used for the statistical quality control process on raw materials and/or the final product. In the traditional concept of the tolerance interval, the variance from the measurements is a single component. However, we can find examples about several components that could vary in their measurements, so an approximate method must be found to modify the traditional tolerance interval. Now we employ a tolerance interval considering multiple components in the variance from the measurements to deal with quality control process. In our paper, the proposed method is used to solve the sample size determination for a two-sided tolerance interval approach considering multiple components on the variance of measurements.  相似文献   
352.
Presented are formulae for an unbiased estimator of a finite population total and an unbiased variance estimator for it when samples are taken by usual procedures in the first two stages with varying probabilities but the third stage units are sampled for economy and convenience in a non-standard way from the pool of all sampled second stage units rather than independently from each of the latter separately containing the former.  相似文献   
353.
We consider estimation of the linear part in a partially linear model for absolutely regular observations. The estimator using random weights are proposed and the asymptotic normality of the estimator is established without compact support assumption.  相似文献   
354.
At least two computer program packages, SPSS and STRATA, use simulated Bernoulli trials to draw (without replacement) a random sample of records from a finite population of records. Therefore, the size of the sample is a random variable. Two estimators of a population total under this sampling procedure are compared with the usual estimator under simple random sampling. Conditions under which the Bernoulli sampling estimators have almost the same mean squared error as the simple random-sample estimator are illustrated.  相似文献   
355.
基于区间数的PROMETHEE Ⅱ方法中权重确定   总被引:2,自引:0,他引:2  
本文引入一种新的区间数距离测度,扩展了可直接处理特征空间为区间数的PROMETHEE Ⅱ多属性决策方法。并在分析属性加权向量ω与最终综合优先序值之间关系的同时,提出了一种基于区间数的PROMETHEE Ⅱ方法的属性权重ω确定原理。应用实例表明了该方法的可行性和有效性,具有推广应用价值。  相似文献   
356.
将决策者在决策指标上存在心理阈值的现状应用到多属性决策问题,提出先对决策目标调整再进行决策的方法。首先,对效益型、成本型、中间型指标构建相应的指标满意度函数和算法,针对不同类型的指标选择相应的算法,计算决策者在每个备选方案存在心理阈值属性上的满意度;其次,根据决策者满意度与心理阈值,调整决策目标组建新的决策信息表;再次,提出基于决策者满意度的属性赋权与信息集结算法模型,获得最优决策方案;最后,通过一个实际生活中的决策者购房案例,表明该方法的科学合理性。  相似文献   
357.
针对筒子纱分拣机器人对作业目标堆叠时识别不准确、抓取位置不稳定的问题,课题组提出了一种堆叠筒子纱的机器人无序分拣方法。构建了具有3D视觉感知的筒子纱分拣机器人系统,利用Kinect V2相机获取堆叠筒子纱的图像信息,对采集到的筒子纱点云进行处理;通过M估计抽样一致性算法(MSAC)和直通滤波算法对原始点云进行裁剪,采用改进E R分割算法和ICP算法完成点云的分割和配准,得到筒子纱的位姿信息;最后使用机器人进行抓取实验。实验结果表明:该方法能够实现对堆叠场景下的作业目标的识别定位,系统的抓取成功率达到86%,可以满足筒子纱分拣的实际生产需求。  相似文献   
358.
    
Selecting the number of observations from each stratum is a primary decision in stratified random sampling design. Typically, allocation schemes aim to minimize or bound the variance associated with estimating some overall population parameter, subject to a limitation on sampling resources. This paper examines the impact of further constraints on allocations for stratified sampling; it was motivated by an application requiring all stratum means to be estimated with equal precision. Simple procedures for analyzing trade-offs between equal-precision allocations and those optimizing total cost or precision of overall population estimates are presented. The effect of equal-precision allocation is illustrated within the context of an anthropological study of eight strata defined by villages. In this example, the equal-precision allocation greatly improves the precision of estimating the stratum-specific means over the customary proportional allocation, with only mild degradation in the precision used to estimate the population mean.  相似文献   
359.
    
The E distribution is the distribution of the empirical log-likelihood ratio for the mean of a multivariate normal distribution. It is the equivalent of Hotelling’s T 2 distribution for the empirical likelihood and is used to calibrate the empirical log-likelihood ratio for finite sample situations. We discuss various aspects of the E distribution, in particular, the estimation of critical values of the E distribution using quantiles of large random samples. We also present tables of estimated critical values for E distributions with 1 to 3 first degrees of freedom.  相似文献   
360.
    
Abstract

In diagnostic trials, clustered data are obtained when several subunits of the same patient are observed. Intracluster correlations need to be taken into account when analyzing such clustered data. A nonparametric method has been proposed by Obuchowski (1997 Obuchowski, N. A. 1997. Nonparametric analysis of clustered ROC curve data. Biometrics 53 (2):56778.[Crossref], [PubMed], [Web of Science ®] [Google Scholar]) to estimate the Receiver Operating Characteristic curve area (AUC) for such clustered data. However, Obuchowski’s estimator is not efficient as it gives equal weight to all pairwise rankings within and between cluster. In this paper, we propose a more efficient nonparametric AUC estimator with two sets of optimal weights. Simulation results show that the loss of efficiency of Obuchowski’s estimator for a single AUC or the AUC difference can be substantial when there is a moderate intracluster test correlation and the cluster size is large. The efficiency gain of our weighted AUC estimator for a single AUC or the AUC difference is further illustrated using the data from a study of screening tests for neonatal hearing.  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