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   1470092篇
  免费   25642篇
  国内免费   6945篇
电工技术   34040篇
综合类   6342篇
化学工业   268308篇
金属工艺   63610篇
机械仪表   40687篇
建筑科学   45043篇
矿业工程   11304篇
能源动力   50145篇
轻工业   106357篇
水利工程   14673篇
石油天然气   37457篇
武器工业   133篇
无线电   195238篇
一般工业技术   276008篇
冶金工业   153057篇
原子能技术   33758篇
自动化技术   166519篇
  2021年   15445篇
  2020年   11722篇
  2019年   14515篇
  2018年   14511篇
  2017年   13812篇
  2016年   20603篇
  2015年   17150篇
  2014年   28489篇
  2013年   87557篇
  2012年   33986篇
  2011年   45373篇
  2010年   41176篇
  2009年   49952篇
  2008年   42756篇
  2007年   39672篇
  2006年   43398篇
  2005年   37905篇
  2004年   40494篇
  2003年   40396篇
  2002年   39667篇
  2001年   36616篇
  2000年   35124篇
  1999年   34148篇
  1998年   42414篇
  1997年   37455篇
  1996年   34097篇
  1995年   29967篇
  1994年   28178篇
  1993年   28149篇
  1992年   25849篇
  1991年   22898篇
  1990年   23324篇
  1989年   22346篇
  1988年   20783篇
  1987年   19098篇
  1986年   18467篇
  1985年   21826篇
  1984年   22172篇
  1983年   20099篇
  1982年   19157篇
  1981年   19263篇
  1980年   17790篇
  1979年   18382篇
  1978年   17648篇
  1977年   17172篇
  1976年   17771篇
  1975年   15901篇
  1974年   15432篇
  1973年   15477篇
  1972年   12982篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Journal of Communications Technology and Electronics - Abstract—The two-dimensional diffraction problem of a plane polarized TM-wave on two identical solid silver nanocylinders is considered....  相似文献   
32.
Wireless Personal Communications - The rapid development of Information and Communication Technology and the growing number of devices connected to the Internet make the Internet of Things (IoT) as...  相似文献   
33.
Metallurgical and Materials Transactions B - The process of obtaining titanium tetrachloride (TiCl4) from the quartz-leucoxene concentrate (QLC) from the Yaregskoe oil-titanium field was studied....  相似文献   
34.
Hassan  Lovelu  Khan  K. A. 《Microsystem Technologies》2020,26(3):1031-1041

The efficiency of any electric cell or battery is very important. To keep it in mind it has been studied the columbic efficiency, voltaic efficiency and energy efficiency of a PKL (Pathor Kuchi Leaf) Quasi Voltaic Cell or Modified Voltaic Cell. It was found that the columbic efficiency data illustrated that this efficiency was lower comparing to other efficiencies may be the absence of salt bridge or separator between the electrodes. Because, our designed and fabricated PKL cell does not have any salt bridge. So that the internal resistance is lower than the traditional voltaic cell and as a result more current was found. The voltage and current changes with time and I–V characteristics for PKL unit cell, module, panel and array have also been studied. It is shown that the voltaic and energy efficiency have been studied. However, the highest efficiency was obtained for 40% PKL sap with 5% secondary salt in 55% aqueous solution, which implies that the concentration of PKL juice can play an important role regarding efficiency. It was also found that the average energy efficiency was 97.43% and it was also found that the average voltaic efficiency was 57.29%. Finally, morphological study FESEM (Field Emission Scanning Electron Microscopy) has also been performed. It is seen that the results confirmed that Zn was deposited on the Cu surface during the electro deposition process in PKL solution. Using AAS, it has been measured the concentration of [Cu2+] as a reactant ion and the concentration of [Zn2+] as a product ion those have been tabulated and graphically discussed. The variation of pH has also been studied with time and which was also tabulated and graphically discussed.

  相似文献   
35.
The use of field robots can greatly decrease the amount of time, effort, and associated risk compared to if human workers were to carryout certain tasks such as disaster response. However, transportability and reliability remain two main issues for most current robot systems. To address the issue of transportability, we have developed a lightweight modularizable platform named AeroArm. To address the issue of reliability, we utilize a multimodal sensing approach, combining the use of multiple sensors and sensor types, and the use of different detection algorithms, as well as active continuous closed‐loop feedback to accurately estimate the state of the robot with respect to the environment. We used Challenge 2 of the 2017 Mohammed Bin Zayed International Robotics Competition as an example outdoor manipulation task, demonstrating the capabilities of our robot system and approach in achieving reliable performance in the fields, and ranked fifth place internationally in the competition.  相似文献   
36.
37.
38.
39.
40.
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