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   147篇
  免费   5篇
管理学   8篇
丛书文集   4篇
理论方法论   4篇
综合类   43篇
社会学   6篇
统计学   87篇
  2021年   1篇
  2020年   3篇
  2019年   5篇
  2018年   1篇
  2017年   4篇
  2016年   1篇
  2015年   3篇
  2014年   3篇
  2013年   54篇
  2012年   9篇
  2011年   4篇
  2010年   7篇
  2009年   5篇
  2008年   5篇
  2007年   3篇
  2006年   5篇
  2005年   9篇
  2004年   4篇
  2003年   3篇
  2002年   1篇
  2001年   5篇
  2000年   3篇
  1999年   1篇
  1998年   2篇
  1997年   1篇
  1996年   2篇
  1995年   3篇
  1994年   1篇
  1987年   1篇
  1985年   1篇
  1980年   1篇
  1979年   1篇
排序方式: 共有152条查询结果,搜索用时 375 毫秒
1.
本文概叙了入世后中国农业面临的农产品品质 安全性及价格的三重冲击和应采取的应对措施 着重分析了农产品安全问题和食品安全保障体系的构建 论述了分析测试技术和科学仪器的七项重任  相似文献   
2.
试卷分析系统的功能与实现   总被引:7,自引:0,他引:7  
试卷分析是教学评估与考核的主要依据和内容,本文采用数理统计方法对试卷进行定量分析,提出了基于经典测量原理的试卷分析方法,并设计开发了相应的分析系统软件。  相似文献   
3.
Many hypothesis tests are univariate tests and cannot cope with multiple hypothesis without an auxiliary procedure as e. g. the Bonferroni-Holm-procedure. At the same time, there is an urgent need for testing multiple hypothesis due to the very simple existing methods as the Bonferroni-correction or the Bonferroni-Holm-procedure, which suffers from a very small local significance level to detect statistical inferences or the drawback that logical and statistical dependencies among the test statistics are not used, whereby its detection is NP-hard. In honour of this occasion, we present a multiple hypothesis test for i.i.d. random variables based on conditional differences in means, which is capable to cope with multiple hypothesis and does not suffer on such drawbacks as the Bonferroni-correction or the Bonferroni-Holm-procedure. Thereby, the computation time can be neglected.  相似文献   
4.
发展机器人产业对上海意义重大,上海机器人产业和技术发展的战略定位须着眼于上海的转型发展和自身的基础。为此,应加强战略引导和资源整合,制定上海机器人产业与技术整体规划和路线图;加强需求的政策引导,发挥本土市场的拉动作用,促进机器人在各领域的应用;吸引大型企业参加应用开发,培育龙头企业;支持中小型企业加速发展,在细分市场形成竞争优势;完善机器人产业园区,提高政策优惠力度;协调整合产、学、研、用和跨学科资源,建立以企业为中枢的研发体系,以促进产业集聚和创新行业。  相似文献   
5.
针对当前移动机器人定位与导航成本较高的问题,提出了一种低成本、高性能的分布式导航方案。以性价比较 高的RPLIDAR激光传感器为核心,采用分布式软件的设计思想,设计了传感器的软件接口;采用DWA方法进行局部路 径规划。设计实现了移动机器人的定位与导航。实验结果表明该方案具有可行性与高效性。  相似文献   
6.
Testing homogeneity of multivariate normal mean vectors under an order restriction when the covariance matrices are unknown, arbitrary positive definite and unequal are considered. This problem of testing has been studied to some extent, for example, by Kulatunga and Sasabuchi (1984 Kulatunga, D. D. S., Sasabuchi, S. (1984). A test of homogeneity of mean vectors against multivariate isotonic alternatives. Mem Fac Sci, Kyushu Univ Ser A Mathemat 38:151161. [Google Scholar]) when the covariance matrices are known and also Sasabuchi et al. (2003 Sasabuchi, S., Tanaka, K., Tsukamodo, T. (2003). Testing homogeneity of multivariate normal mean vectors under an order restriction when the covariance matrices are common but unknown. Annals of Statistics. 31(5):15171536.[Web of Science ®] [Google Scholar]) and Sasabuchi (2007 Sasabuchi, S. (2007). More powerful tests for homogeneity of multivariate normal mean vectors under an order restriction. Sankhya 69(4):700716. [Google Scholar]) when the covariance matrices are unknown but common. In this paper, a test statistic is proposed and because of the main advantage of the bootstrap test is that it avoids the derivation of the complex null distribution analytically, a bootstrap test statistic is derived and since the proposed test statistic is location invariance the bootstrap p-value defined logical and some steps are presented to estimate it. Our numerical studies via Monte Carlo simulation show that the proposed bootstrap test can correctly control the type I error rates. The power of the test for some of the p-dimensional normal distributions is computed by Monte Carlo simulation. Also, the null distribution of test statistic is estimated using kernel density. Finally, the bootstrap test is illustrated using a real data.  相似文献   
7.
本文介绍了自行研制的冰箱化霜温控开关温度特性全自动测试合,它每次检测数可达100只,工作槽温度场均匀性在±0.1℃以内,控温精度达±02℃.文中对其设计原理、系统流程及控制系统等作了详细描述.  相似文献   
8.
The empirical likelihood ratio (ELR) test for the problem of testing for normality is derived in this article. The sampling properties of the ELR test and four other commonly used tests are provided and analyzed using the Monte Carlo simulation technique. The power comparisons against a wide range of alternative distributions show that the ELR test is the most powerful of these tests in certain situations.  相似文献   
9.
In computational sciences, including computational statistics, machine learning, and bioinformatics, it is often claimed in articles presenting new supervised learning methods that the new method performs better than existing methods on real data, for instance in terms of error rate. However, these claims are often not based on proper statistical tests and, even if such tests are performed, the tested hypothesis is not clearly defined and poor attention is devoted to the Type I and Type II errors. In the present article, we aim to fill this gap by providing a proper statistical framework for hypothesis tests that compare the performances of supervised learning methods based on several real datasets with unknown underlying distributions. After giving a statistical interpretation of ad hoc tests commonly performed by computational researchers, we devote special attention to power issues and outline a simple method of determining the number of datasets to be included in a comparison study to reach an adequate power. These methods are illustrated through three comparison studies from the literature and an exemplary benchmarking study using gene expression microarray data. All our results can be reproduced using R codes and datasets available from the companion website http://www.ibe.med.uni-muenchen.de/organisation/mitarbeiter/020_professuren/boulesteix/compstud2013.  相似文献   
10.
本文提出了一种在工厂装配线上对成批的近红外线发光二极管和光电二极管进行筛选的工艺,并为此设计了一台实用的检测装置。  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