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   1526213篇
  免费   26212篇
  国内免费   6987篇
电工技术   34261篇
综合类   6489篇
化学工业   271954篇
金属工艺   64124篇
机械仪表   42758篇
建筑科学   47153篇
矿业工程   11377篇
能源动力   50252篇
轻工业   118251篇
水利工程   15503篇
石油天然气   37291篇
武器工业   137篇
无线电   196445篇
一般工业技术   288146篇
冶金工业   170449篇
原子能技术   33793篇
自动化技术   171029篇
  2021年   15669篇
  2020年   11867篇
  2019年   14650篇
  2018年   14880篇
  2017年   14084篇
  2016年   21112篇
  2015年   17410篇
  2014年   28824篇
  2013年   87965篇
  2012年   36257篇
  2011年   48571篇
  2010年   42268篇
  2009年   50422篇
  2008年   45429篇
  2007年   42650篇
  2006年   45668篇
  2005年   39922篇
  2004年   42483篇
  2003年   42324篇
  2002年   41374篇
  2001年   38386篇
  2000年   36655篇
  1999年   35631篇
  1998年   46953篇
  1997年   40593篇
  1996年   36351篇
  1995年   31520篇
  1994年   29563篇
  1993年   29110篇
  1992年   26539篇
  1991年   23633篇
  1990年   23878篇
  1989年   22957篇
  1988年   21454篇
  1987年   19726篇
  1986年   19190篇
  1985年   22576篇
  1984年   22693篇
  1983年   20572篇
  1982年   19429篇
  1981年   19492篇
  1980年   18098篇
  1979年   18744篇
  1978年   17924篇
  1977年   17988篇
  1976年   19539篇
  1975年   16111篇
  1974年   15646篇
  1973年   15722篇
  1972年   13209篇
排序方式: 共有10000条查询结果,搜索用时 0 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