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   539篇
  免费   17篇
  国内免费   3篇
管理学   29篇
民族学   1篇
人口学   2篇
丛书文集   11篇
理论方法论   6篇
综合类   301篇
社会学   32篇
统计学   177篇
  2023年   3篇
  2021年   3篇
  2020年   13篇
  2019年   11篇
  2018年   19篇
  2017年   28篇
  2016年   18篇
  2015年   23篇
  2014年   22篇
  2013年   75篇
  2012年   26篇
  2011年   27篇
  2010年   34篇
  2009年   23篇
  2008年   31篇
  2007年   35篇
  2006年   36篇
  2005年   32篇
  2004年   17篇
  2003年   10篇
  2002年   6篇
  2001年   11篇
  2000年   9篇
  1999年   7篇
  1998年   6篇
  1997年   3篇
  1996年   11篇
  1995年   5篇
  1994年   4篇
  1992年   4篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
  1978年   1篇
排序方式: 共有559条查询结果,搜索用时 421 毫秒
1.
Summary.  As a part of the EUREDIT project new methods to detect multivariate outliers in incomplete survey data have been developed. These methods are the first to work with sampling weights and to be able to cope with missing values. Two of these methods are presented here. The epidemic algorithm simulates the propagation of a disease through a population and uses extreme infection times to find outlying observations. Transformed rank correlations are robust estimates of the centre and the scatter of the data. They use a geometric transformation that is based on the rank correlation matrix. The estimates are used to define a Mahalanobis distance that reveals outliers. The two methods are applied to a small data set and to one of the evaluation data sets of the EUREDIT project.  相似文献   
2.
提出了一种基于移动代理的新型分布式入侵检测系统。该系统是针对广域网环境专门设计的,数据的处理通过各节点所设置的代理来进行分布式计算,不仅能实现全网络范围内的入侵检测功能,具有良好的可移植性;而且对网络系统和主机的资源占用较低,减少了出现网络瓶颈的可能。还建立了移动代理的新型分布式入侵检测系统的体系结构和理论分析模型,并讨论了该系统的维护更新机制。  相似文献   
3.
遗传算法在入侵检测中的应用   总被引:4,自引:0,他引:4  
介绍了基于模型推理和基于模型两种入侵检测系统,提出了一种新的基于智能体技术的入侵检测系统体系结构,解决了传统集中式入侵检测系统的弊病,将任务处理和数据分布到网络各个结点上,充分利用网络资源协同完成入侵检测任务;介绍了遗传算法在该系统中的应用,因系统安全的先验知识体现在对原始数据中有价值特征属性变量集的选择上,故利用遗传算法对特征属性变量子集的选择进行优化,找到相对最优的由特征向量表示的特征属性变量集,以降低入侵检测系统的负荷。  相似文献   
4.
本文从CCD图象输入系统误差引起图象检测信号失真的原因分析出发,以降低系统装校误差精度要求和增大元器件离散性的宽容度为目标,讨论朱真校正方法的原理和数学描述。最后,介绍两种失真校正方法。  相似文献   
5.
汉语学现代转型的前提批判   总被引:2,自引:2,他引:0  
在漫长的历史发展过程中,西方语言文字(印欧语)是沿着音声中心/文字弱化的路径演变的,音义二极性是西方语言学的大前提。而汉语言文字自秦汉以来发生的形态类型简化和汉字形声化的整体演变趋势,则是音声弱化/文字中心的演变路径,形音义三极性是汉语学的大前提。由于中西语言文字类型的体制性差异,汉语学理应把现代转型理解成一个包含三重辩证对立同一关系的概念体系:对立于传统,即现代与前现代应在本体论上实现辩证同一;对立于自身,即元语言与对象语言、主观语法与客观语法应在认识论上实现辩证同一;对立于西方,即个性与共性、民族性与现代性应在方法论上实现辩证同一。  相似文献   
6.
稳频横向塞曼He-Ne激光器作为一种新型光源,具有功率大、频差低、易于相位细分的特点,因而能广泛应用于各种精密测量中.本文介绍了我们研制的稳频横向塞曼激光器,实验结果表明,其激光频率稳定度达4.7×10(-10),再现性达1.8×10(-8).  相似文献   
7.
Multivariate control charts are used to monitor stochastic processes for changes and unusual observations. Hotelling's T2 statistic is calculated for each new observation and an out‐of‐control signal is issued if it goes beyond the control limits. However, this classical approach becomes unreliable as the number of variables p approaches the number of observations n, and impossible when p exceeds n. In this paper, we devise an improvement to the monitoring procedure in high‐dimensional settings. We regularise the covariance matrix to estimate the baseline parameter and incorporate a leave‐one‐out re‐sampling approach to estimate the empirical distribution of future observations. An extensive simulation study demonstrates that the new method outperforms the classical Hotelling T2 approach in power, and maintains appropriate false positive rates. We demonstrate the utility of the method using a set of quality control samples collected to monitor a gas chromatography–mass spectrometry apparatus over a period of 67 days.  相似文献   
8.
Child sexual abuse is one of the main types of abuse still to be addressed within the field of education, yet the education system itself can serve as a primary tool for its prevention. A better understanding of teachers’ knowledge and beliefs about child sexual abuse will allow us to establish key starting points from which to utilize the system for prevention. Four hundred and fifty teachers participated in this study, completing a questionnaire regarding their knowledge and beliefs about child sexual abuse. The study revealed that over half the teachers, 65.3% (n = 294), had never received any type of training in child sexual abuse education and that the majority were not familiar with methods of identifying child sexual abuse, 90.7% (n = 279). Various mistaken beliefs were identified among the participating teachers, such as pathological profiles of abusers, that the vast majority of child sexual abuse implies violent behavior, and that there cannot be abusers the same age as the victim. These results indicate that knowledge deficiencies do exist about child sexual abuse among teachers and highlight the need for training in this field.  相似文献   
9.
Feature extraction from observed noisy samples is a common important problem in statistics and engineering. This paper presents a novel general statistical approach to the region detection problem in long data sequences. The proposed technique is a multiscale kernel regression in conjunction with statistical multiple testing for region detection while controlling the false discovery rate (FDR) and maximizing the signal-to-noise ratio via matched filtering. This is achieved by considering a one-dimensional region detection problem as its equivalent zero-dimensional peak detection problem. The detection method does not require a priori knowledge of the shape of the nonzero regions. However, if the shape of the nonzero regions is known a priori, e.g., rectangular pulse, the signal regions can also be reconstructed from the detected peaks, seen as their topological point representatives. Simulations show that the method can effectively perform signal detection and reconstruction in the simulated data under high noise conditions, while controlling the FDR of detected regions and their reconstructed length.  相似文献   
10.
利用互联网环境,从技术的角度出发,对一稿多投、抄袭行为、剽窃行为以及捏造行为等学术不端行为的检测与防范进行研究,提出了各种操作上可行的方法。实践证明,运用这些方法,可有效地防范有学术不端行为的文章在学术期刊上发表。  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