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   17520篇
  免费   1181篇
  国内免费   957篇
电工技术   863篇
技术理论   4篇
综合类   2643篇
化学工业   593篇
金属工艺   210篇
机械仪表   728篇
建筑科学   1135篇
矿业工程   256篇
能源动力   102篇
轻工业   232篇
水利工程   198篇
石油天然气   257篇
武器工业   198篇
无线电   3155篇
一般工业技术   609篇
冶金工业   1395篇
原子能技术   23篇
自动化技术   7057篇
  2024年   89篇
  2023年   273篇
  2022年   498篇
  2021年   667篇
  2020年   685篇
  2019年   378篇
  2018年   321篇
  2017年   472篇
  2016年   542篇
  2015年   592篇
  2014年   1292篇
  2013年   1161篇
  2012年   1353篇
  2011年   1419篇
  2010年   1096篇
  2009年   893篇
  2008年   803篇
  2007年   857篇
  2006年   823篇
  2005年   770篇
  2004年   712篇
  2003年   740篇
  2002年   747篇
  2001年   639篇
  2000年   562篇
  1999年   389篇
  1998年   197篇
  1997年   115篇
  1996年   72篇
  1995年   46篇
  1994年   28篇
  1993年   20篇
  1992年   21篇
  1990年   12篇
  1989年   17篇
  1988年   17篇
  1987年   14篇
  1986年   16篇
  1984年   15篇
  1966年   19篇
  1965年   12篇
  1962年   14篇
  1961年   11篇
  1960年   11篇
  1959年   21篇
  1958年   19篇
  1957年   20篇
  1956年   16篇
  1955年   19篇
  1954年   16篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Geometric dimensioning and tolerancing (GD&T) is a method to specify the dimensions and form of a part so that it will meet its design intent. GD&T is difficult to master for two main reasons. First, it is based on complex 3D geometric entities and relationships. Second, the geometry is associated with a large, diverse knowledge base of dimensional metrology with many interconnections. This paper describes an approach to create a dimensional metrology knowledge base that is organized around a set of key concepts and to represent those concepts as virtual objects that can be navigated with interactive, computer visualization techniques to access the associated knowledge. The approach can enable several applications. First is the application to convey the definition and meaning of GD&T over a broad range of tolerance types. Second is the application to provide a visualization of dimensional metrology knowledge within a control hierarchy of the inspection process. Third is the application to show the coverage of interoperability standards to enable industry to make decisions on standards development and harmonization efforts. A prototype system has been implemented to demonstrate the principles involved in the approach.  相似文献   
32.
How can psychologists and graduate students become more affirmative of lesbian, gay, bisexual, and transgender (LGBT) issues? Safe Zone is a diversity-training program to increase sensitivity toward, knowledge of, and advocacy for LGBT populations and issues that affect them. In this exploratory study, the implementation of Safe Zone is described within a school of professional psychology; its effectiveness was assessed by self-reported behavioral and attitudinal changes and from participant evaluations. Results were encouraging with regard to the goals of Safe Zone and its adaptation to institutions interested in improving relations with the LGBT community, but additional empirical studies are needed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
33.
Provides the biography of David W. Johnson and announces that he has won the Award for Distinguished Contributions of Applications of Psychology to Education and Training for programmatic research, comprehensive research reviews, and revision of theory over four decades of persistence that have provided the knowledge foundation for cooperative learning, constructive controversy, conflict resolution, and peer mediation training. A selected bibliography is also provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
34.
B737机务CBT系统建设方案的探讨   总被引:3,自引:0,他引:3  
通过对AICC制订的CBT课件开发规范的探讨,阐述了CBT的基本概念和波音737飞机机务CBT的开发制作过程,以及利用Authorware开发软件制作多媒体课件的技术难点。  相似文献   
35.
简要介绍了电子编号的起源、原理、特点和存在的问题。  相似文献   
36.
IPv6和基于IPv6的网络设计   总被引:2,自引:0,他引:2  
对IPv6协议的主要内容进行了简要介绍,并针对IPv6的特点对基于IPv6的网络设计进行了探讨。  相似文献   
37.
基于因特网的远程校准技术进展   总被引:3,自引:0,他引:3  
远程校准是信息技术特别是计算机网络技术与传统的计量测试技术结合的必然产物。本文介绍与之有关的一些概念及国外开展相应项目的情况。结合我们自己的一个实验装置.对在我国开展远程校准工作的必要性和可行性提出一些看法。  相似文献   
38.
本文对广钢创建学习型企业和搞好职工培训工作的问题进行了探讨,提出了在创建学习型企业过程中,加强和改进职工培训工作的思路和办法。  相似文献   
39.
According to the knowledge partitioning framework, people sometimes master complex tasks by creating multiple independent parcels of partial knowledge. Research has shown that knowledge parcels may contain mutually contradictory information, and that each parcel may be used without regard to knowledge that is demonstrably present in other parcels. This article reports 4 experiments that investigated knowledge partitioning in categorization. When component boundaries of a complex categorization were identified by a context cue, a significant proportion of participants learned partial and independent categorization strategies that were chosen on the basis of context. For those participants, a strategy used in one context was unaffected by knowledge demonstrably present in other contexts, suggesting that knowledge partitioning in categorization can be complete. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
40.
Three experiments investigated the effects of varying the conditioned stimulus (CS) duration between training and extinction. Ring doves (Streptopelia risoria) were autoshaped on a fixed CS-unconditioned stimulus (US) interval and extinguished with CS presentations that were longer, shorter, or the same as the training duration. During a subsequent test session, the training CS duration was reintroduced. Results suggest that the cessation of responding during an extinction session is controlled by generalization of excitation between the training and extinction CSs and by the number of nonreinforced CS presentations. Transfer of extinction to the training CS is controlled by the similarity between the extinction and training CSs. Extinction learning is temporally specific. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  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