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   825032篇
  免费   79093篇
  国内免费   49053篇
电工技术   39488篇
技术理论   5篇
综合类   21838篇
化学工业   120352篇
金属工艺   48403篇
机械仪表   24851篇
建筑科学   27527篇
矿业工程   16003篇
能源动力   24446篇
轻工业   81010篇
水利工程   13723篇
石油天然气   22633篇
武器工业   3777篇
无线电   105347篇
一般工业技术   152792篇
冶金工业   130263篇
原子能技术   14540篇
自动化技术   106180篇
  2022年   7344篇
  2021年   10248篇
  2020年   12139篇
  2019年   22619篇
  2018年   27196篇
  2017年   28514篇
  2016年   29008篇
  2015年   25226篇
  2014年   27815篇
  2013年   46431篇
  2012年   33048篇
  2011年   35908篇
  2010年   29644篇
  2009年   28908篇
  2008年   28397篇
  2007年   28081篇
  2006年   24546篇
  2005年   22209篇
  2004年   24209篇
  2003年   22329篇
  2002年   21469篇
  2001年   20872篇
  2000年   19159篇
  1999年   19711篇
  1998年   41414篇
  1997年   30283篇
  1996年   23946篇
  1995年   18908篇
  1994年   16661篇
  1993年   16320篇
  1992年   12545篇
  1991年   11475篇
  1990年   10977篇
  1989年   10618篇
  1988年   9818篇
  1987年   8049篇
  1986年   7968篇
  1985年   9065篇
  1984年   8430篇
  1983年   7726篇
  1982年   7098篇
  1981年   7386篇
  1980年   6904篇
  1979年   6740篇
  1978年   6614篇
  1977年   7222篇
  1976年   9494篇
  1975年   5803篇
  1974年   5431篇
  1973年   5501篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
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   
82.
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   
83.
Photonic Network Communications - Optical packet switching is a prominent technology proposing not only a reduction in the energy consumption by the elimination of numerous...  相似文献   
84.
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   
85.
86.
87.
88.

Stability constants and formation enthalpies of supramolecular complexes of crown ethers and their cyclic and acyclic analogues are determined on the basis of experimental data obtained by different physicochemical methods in the terms of a general approach developed and implemented in the ChemEqui software package. The established regularities of variation of stability of complexes are discussed as dependent on the ligand structure, nature of the cation, solvent, and anion. The applicability of the suggested method of determining complexation selectivity is shown for multicomponent equilibria in solutions.

  相似文献   
89.
Lobster krill (Munida genus) represents an under‐valued crustacean frequently caught on European fishing banks. In this work, its sensory, microbiological and biochemical qualities were evaluated during chilled storage. Additionally, the effects of a prestorage antimelanosic treatment consisting of soaking in sodium metabisulphite (SMB) solutions at two different concentrations (0.25% and 0.75%) were also studied. SMB prestorage treatment provided lobster specimens that still exhibited acceptable sensory quality after 10 days of storage, while control specimens were unacceptable at that time. SMB treatment also resulted in a significant (P < 0.05) inhibition of microbial growth, mainly of Enterobacteriaceae, psychrotrophes and proteolytic bacteria. Low lipid oxidation levels were observed for all batches; however, a significantly higher (P < 0.05) retention of polyunsaturated fatty acids was found in SMB‐treated lobster, especially in the 0.75% SMB batch. The results presented here open the way to the potential commercialisation of currently under‐utilised lobster krill as a chilled product.  相似文献   
90.
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