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   1610721篇
  免费   28246篇
  国内免费   7057篇
电工技术   34987篇
综合类   6596篇
化学工业   262757篇
金属工艺   66494篇
机械仪表   47558篇
建筑科学   46231篇
矿业工程   11939篇
能源动力   50149篇
轻工业   126588篇
水利工程   16805篇
石油天然气   37432篇
武器工业   155篇
无线电   200359篇
一般工业技术   305720篇
冶金工业   221195篇
原子能技术   34736篇
自动化技术   176323篇
  2021年   14741篇
  2020年   12026篇
  2019年   14824篇
  2018年   19377篇
  2017年   19195篇
  2016年   23364篇
  2015年   17825篇
  2014年   28978篇
  2013年   88506篇
  2012年   39788篇
  2011年   55645篇
  2010年   46900篇
  2009年   54293篇
  2008年   50839篇
  2007年   49112篇
  2006年   48125篇
  2005年   43981篇
  2004年   45262篇
  2003年   44013篇
  2002年   40984篇
  2001年   37828篇
  2000年   35100篇
  1999年   35385篇
  1998年   59689篇
  1997年   47807篇
  1996年   39872篇
  1995年   34578篇
  1994年   31849篇
  1993年   31439篇
  1992年   26841篇
  1991年   24258篇
  1990年   24512篇
  1989年   23492篇
  1988年   22039篇
  1987年   20242篇
  1986年   19782篇
  1985年   23184篇
  1984年   22802篇
  1983年   20682篇
  1982年   19484篇
  1981年   19548篇
  1980年   18260篇
  1979年   18768篇
  1978年   17968篇
  1977年   18779篇
  1976年   21413篇
  1975年   16142篇
  1974年   15632篇
  1973年   15757篇
  1972年   13299篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
91.
Journal of Materials Science: Materials in Electronics - Nonlinear optical organometallic single crystal of manganese mercury thiocyanate (MMTC) has been grown by SR method in aqueous solution. The...  相似文献   
92.
Journal of Materials Science: Materials in Electronics - Sn–Zn–Cu is one of the most popular soldering alloys, especially when it has been doped with Bi, which has proved very...  相似文献   
93.

ResearchGate has emerged as a popular professional network for scientists and researchers in a very short span. Similar to Google Scholar, the ResearchGate indexing uses an automatic crawling algorithm that extracts bibliographic data, citations, and other information about scholarly articles from various sources. However, it has been observed that the two platforms often show different publication and citation data for the same institutions, journals, and authors. While several previous studies analysed different aspects of ResearchGate and Google Scholar, the quantum of differences in publications, citations, and metrics between the two and the probable reasons for the same are not explored much. This article, therefore, attempts to bridge this research gap by analysing and measuring the differences in publications, citations, and different metrics of the two platforms for a large data set of highly cited authors. The results indicate that there are significantly high differences in publications and citations for the same authors captured by the two platforms, with Google Scholar having higher counts for a vast majority of the cases. The different metrics computed by the two platforms also differ in their values, showing different degrees of correlation. The coverage policy, indexing errors, author attribution mechanism, and strategy to deal with predatory publishing are found to be the main probable reasons for the differences in the two platforms.

  相似文献   
94.
Filtration Waves     
Journal of Engineering Physics and Thermophysics - Equations and relations have been obtained for describing one-dimensional filtration waves in a homogeneous isotropic porous medium in plane,...  相似文献   
95.
Journal of Engineering Physics and Thermophysics - A laminar boundary layer in a gas flow near a disk rotating at a constant angular velocity under the conditions of a significant radial...  相似文献   
96.
Journal of Engineering Physics and Thermophysics - An overview of the development of mathematical models used to describe the relationship between the parameters of the state of real gases is...  相似文献   
97.
Kulemin  V. V.  Martynov  K. V.  Krasavina  E. P.  Rumer  I. A.  Kulyukhin  S. A. 《Radiochemistry》2022,64(2):158-163
Radiochemistry - The distribution of uranium between different phases of cast stone matrices fabricated by fusion of basalt and uranium-bearing SiO2-based collectors was investigated. It was found...  相似文献   
98.
Savruk  M. P.  Kravets  V. S.  Chornenkyi  A. B. 《Materials Science》2022,57(4):492-501
Materials Science - We develop an analytic-numerical algorithm for the determination of the optimal shape of smooth holes (with minimum stress concentration) in quasiorthotropic plates subjected to...  相似文献   
99.
Journal of Engineering Physics and Thermophysics - The possibility of intensifying the drying of materials by noncontact ultrasonic action at a frequency of 22 kHz at sound pressure levels up to...  相似文献   
100.
Yakunin  S. A. 《Radiochemistry》2022,64(4):482-490
Radiochemistry - As applied to the radioactive waste vitrification technology, published data on the behavior of cesium and its release into the gas phase are reviewed. The volatility of cesium...  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