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   1686篇
  免费   61篇
  国内免费   43篇
电工技术   124篇
综合类   48篇
化学工业   147篇
金属工艺   271篇
机械仪表   225篇
建筑科学   75篇
矿业工程   33篇
能源动力   29篇
轻工业   24篇
水利工程   13篇
石油天然气   23篇
武器工业   5篇
无线电   152篇
一般工业技术   157篇
冶金工业   242篇
原子能技术   18篇
自动化技术   204篇
  2023年   11篇
  2022年   13篇
  2021年   31篇
  2020年   27篇
  2019年   10篇
  2018年   18篇
  2017年   33篇
  2016年   41篇
  2015年   33篇
  2014年   90篇
  2013年   110篇
  2012年   96篇
  2011年   98篇
  2010年   79篇
  2009年   74篇
  2008年   83篇
  2007年   94篇
  2006年   108篇
  2005年   94篇
  2004年   98篇
  2003年   88篇
  2002年   60篇
  2001年   46篇
  2000年   52篇
  1999年   44篇
  1998年   26篇
  1997年   40篇
  1996年   19篇
  1995年   27篇
  1994年   22篇
  1993年   12篇
  1992年   9篇
  1991年   7篇
  1990年   12篇
  1989年   11篇
  1988年   7篇
  1987年   8篇
  1984年   6篇
  1982年   3篇
  1979年   3篇
  1969年   2篇
  1967年   3篇
  1966年   2篇
  1965年   4篇
  1964年   2篇
  1962年   2篇
  1961年   3篇
  1958年   2篇
  1956年   4篇
  1955年   2篇
排序方式: 共有1790条查询结果,搜索用时 15 毫秒
1.
针对传统的电弧电路故障检测结果不准确的问题,设计用于电弧检测的SoC系统,并且在55nm工艺下进行流片验证。采用包含两种结构的模数转换器的片上电压源,设计了锁相环以及复位电路,精度最高可达8.67 bit。验证结果表明,本设计可提高电弧检测的准确性。  相似文献   
2.
This paper introduces the potential feasibility that ELID (electrolytic in-process dressing) grinding replaces superfinishing in bearing manufacturing, but ELID grinding will bring new challenges. Different regions present distinguish surface profile due to the non-uniform contact in ELID groove grinding. However, few reports explaining the non-uniform contact are available. This article explores the mechanisms of the non-uniform contact during ELID groove grinding. Experiments on the non-uniform contact between bearing raceway and grinding wheel have been carried out under different conditions. The results show that non-uniform contact exists in ELID groove grinding process and it exerts influence on the profile of the raceway surface. Non-uniform contact influences the Rsk and Rku value all the time, but it influences the Ra value occasionally. Improvement strategies of eliminating the non-uniform contact are also discussed based on the experimental study.  相似文献   
3.
该文针对当前电子白板系统对个性化支持的不足,引入手写笔作为输入设备,充分利用其功能参数,设计开发了具有模拟毛笔、钢笔、铅笔等真实笔特征的多笔型功能的电子白板系统。  相似文献   
4.
Introduces the current issue of the American Psychologist, which examines the ramifications of the Brown vs. Board of Education decision and its sequelae over the last 50 years, with a special focus on the mixed role of psychological research and practice. Despite the great strides toward a more just society since May 17, 1954, inequities remain in schooling, in social relations, and in economic opportunity. How will history judge American psychology 50 years from now vis-a-vis the possibilities it helped create via Brown? The articles in this special issue suggest several important directions of research and action our field will need to take if the verdict of history is to be a positive one. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
数字程序控制计算机辅助教学是将计算机技术用于数字程序控制的教学过程,它帮助学生学习并模拟教学实验.本文介绍了数字程序控制中直线插补和圆孤插补的CAI实现方法.  相似文献   
6.
Two different control systems were developed using quantitative feedback theory for weld quality improvement. The first application to be discussed was designed for the resistance pinch welding process and uses electrode displacement and force as feedback parameters. A correlation between weld quality and electrode displacement is established for constant electrode force. The system is capable of producing repeatable welds of consistent quality, with wide variations in weld parameters. This is the first time feedback control has been successfully applied to pinch welding. The second example presented in this paper was developed for penetration control of the gas-tungsten-arc welding process. The feedback signal is obtained by measuring the amount of light emitted from the back side of the weld. Welds of constant penetration have been demonstrated in tests with travel speeds varying from 1.5 to 6 inches per minute and with 200 per cent changes in part thickness.  相似文献   
7.
8.
This article describes the role of certification by the American Board of Professional Psychology (ABPP) in easing the process by which psychologists move beyond their original jurisdictional boundaries to practice psychology. Meeting the requirements for licensure or certification in the various jurisdictions can be a difficult task because these requirements vary considerably from jurisdiction to jurisdiction. Other mechanisms that are available to facilitate this process include the Certificate of Professional Qualification in Psychology issued by the Association of State and Provincial Psychology Boards and certification by the National Register of Health Service Providers in Psychology. The ABPP certificate/diploma has been regarded by many state psychological associations and state boards of psychology as an appropriate way in which to recognize psychologists who are eligible for licensure/certification in a jurisdiction because of the examination requirements for board certification. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
This is the last part of a four-part survey of optimization models and solution algorithms for winter road maintenance planning. The two first parts of the survey address system design problems for winter road maintenance. The third part concentrates mainly on vehicle routing problems for spreading operations. The aim of this paper is to provide a comprehensive survey of optimization models and solution methodologies for the routing of vehicles for plowing and snow disposal operations. We also review models for the fleet sizing and fleet replacement problems.  相似文献   
10.
A new type of arc plasma reactor with 12-phase alternating current (AC) discharge for synthesis of carbon nanotubes (CNTs) is proposed. A couple of six discharge electrodes by which have mutually electrical connection between them to enlarge the high-temperature regions in the reactor are arranged to three-dimensional locations. A new method of CNTs fabrication by this reactor, which accomplishes to enlarge the suitable growth region in high purity and at high yield, was developed.  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