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   333102篇
  免费   24064篇
  国内免费   12537篇
电工技术   17926篇
技术理论   56篇
综合类   19696篇
化学工业   56554篇
金属工艺   18550篇
机械仪表   21181篇
建筑科学   25724篇
矿业工程   10968篇
能源动力   9780篇
轻工业   18643篇
水利工程   5260篇
石油天然气   22979篇
武器工业   2599篇
无线电   36662篇
一般工业技术   39790篇
冶金工业   18386篇
原子能技术   3218篇
自动化技术   41731篇
  2024年   1295篇
  2023年   5224篇
  2022年   8877篇
  2021年   12531篇
  2020年   9837篇
  2019年   8014篇
  2018年   9209篇
  2017年   10383篇
  2016年   9284篇
  2015年   12224篇
  2014年   15880篇
  2013年   19188篇
  2012年   20169篇
  2011年   22447篇
  2010年   19202篇
  2009年   18332篇
  2008年   17975篇
  2007年   17405篇
  2006年   18288篇
  2005年   16134篇
  2004年   10346篇
  2003年   9129篇
  2002年   8136篇
  2001年   7472篇
  2000年   8003篇
  1999年   9654篇
  1998年   8159篇
  1997年   6770篇
  1996年   6363篇
  1995年   5339篇
  1994年   4379篇
  1993年   3089篇
  1992年   2492篇
  1991年   1961篇
  1990年   1508篇
  1989年   1232篇
  1988年   1019篇
  1987年   681篇
  1986年   535篇
  1985年   342篇
  1984年   243篇
  1983年   204篇
  1982年   196篇
  1981年   129篇
  1980年   130篇
  1979年   67篇
  1978年   33篇
  1977年   38篇
  1976年   55篇
  1975年   20篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
152.
153.
154.
155.
156.
157.
The thick film of Zn-Sb-O was prepared by coating the paste of nanoparticles mixture (Sb2O3:ZnO=1:3) on the alumina substrate, followed by sintering at 500-900 °C for 2 h in air. The electrical resistance and gas-sensing properties to benzene, alcohol and acetone of Zn-Sb-O films were found to be dependent on the change of phase structure caused by sintering temperature.  相似文献   
158.
Polyurethane elastomer composites were developed using milled fiberglass and their mechanical properties were studied. In particular, the organically chemical treatment of the milled fiberglass was investigated in detail. It was demonstrated that both strength and toughness of the resulting elastomer composites were improved considerably with the addition content of fiberglass. Furthermore, it was indicated that the optimal properties can be achieved by the proper addition of milled fiberglass that was chemically treated using coupling agent.  相似文献   
159.
Ultra-wideband bandpass filter with hybrid microstrip/CPW structure   总被引:4,自引:0,他引:4  
A novel ultra-wideband (UWB) bandpass filter (BPF) is presented using the hybrid microstrip and coplanar waveguide (CPW) structure. A CPW nonuniform resonator or multiple-mode resonator (MMR) is constructed to produce its first three resonant modes occurring around the lower end, center, and higher end of the UWB band. Then, a microstrip/CPW surface-to-surface coupled line is formed and modeled to allocate the enhanced coupling peak around the center of this UWB band, i.e., 6.85GHz. As such, a five-pole UWB BPF is built up and realized with the passband covering the entire UWB band (3.1-10.6GHz). A predicted frequency response is finally verified by the experiment. In addition, the designed UWB filter, with a single resonator, only occupies one full-wavelength in length or 16.9mm.  相似文献   
160.
Global competition is driving manufacturing companies to change the way they do business. New kinds of shop floor control systems need to be implemented for these companies to respond quickly to changing shop floor environments and customer demands. This paper presents a new concept called iShopFloor-an intelligent shop floor based on the Internet, web, and agent technologies. It focuses on the implementation of distributed intelligence in the manufacturing shop floor. The proposed approach provides the framework for components of a complex control system to work together as a whole rather than as a disjoint set. It encompasses both information architecture and integration methodologies. The paper introduces the basic concept of iShopFloor, a generic system architecture, and system components. It also describes the implementation of eXtensible Markup Language message services in iShopFloor and the application of intelligent agents to distributed manufacturing scheduling. A prototype environment is presented, and some implementation issues are discussed.  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