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   1458546篇
  免费   27037篇
  国内免费   6859篇
电工技术   34107篇
综合类   6352篇
化学工业   266939篇
金属工艺   63603篇
机械仪表   40965篇
建筑科学   45028篇
矿业工程   11360篇
能源动力   50175篇
轻工业   106673篇
水利工程   14694篇
石油天然气   37445篇
武器工业   132篇
无线电   194913篇
一般工业技术   276404篇
冶金工业   142801篇
原子能技术   33836篇
自动化技术   167015篇
  2021年   15411篇
  2020年   11741篇
  2019年   14511篇
  2018年   14828篇
  2017年   14184篇
  2016年   20834篇
  2015年   17207篇
  2014年   28543篇
  2013年   87595篇
  2012年   34108篇
  2011年   45882篇
  2010年   41614篇
  2009年   50213篇
  2008年   43031篇
  2007年   40063篇
  2006年   43539篇
  2005年   38119篇
  2004年   40480篇
  2003年   40435篇
  2002年   39589篇
  2001年   36202篇
  2000年   34934篇
  1999年   33630篇
  1998年   38190篇
  1997年   35190篇
  1996年   32734篇
  1995年   29124篇
  1994年   27615篇
  1993年   27463篇
  1992年   25838篇
  1991年   22771篇
  1990年   23169篇
  1989年   22225篇
  1988年   20775篇
  1987年   19110篇
  1986年   18422篇
  1985年   21753篇
  1984年   22092篇
  1983年   20060篇
  1982年   19103篇
  1981年   19210篇
  1980年   17804篇
  1979年   18398篇
  1978年   17616篇
  1977年   17126篇
  1976年   17719篇
  1975年   15938篇
  1974年   15439篇
  1973年   15508篇
  1972年   12975篇
排序方式: 共有10000条查询结果,搜索用时 181 毫秒
211.
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   
212.
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   
213.
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   
214.
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   
215.
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   
216.
217.
218.
219.
220.
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