首页 | 官方网站   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   1644937篇
  免费   30710篇
  国内免费   8147篇
工业技术   1683794篇
  2021年   15877篇
  2020年   12894篇
  2019年   15501篇
  2018年   18689篇
  2017年   18202篇
  2016年   23520篇
  2015年   18855篇
  2014年   30462篇
  2013年   90300篇
  2012年   41353篇
  2011年   56157篇
  2010年   47034篇
  2009年   54406篇
  2008年   51429篇
  2007年   49179篇
  2006年   49741篇
  2005年   44588篇
  2004年   45865篇
  2003年   45429篇
  2002年   43648篇
  2001年   38830篇
  2000年   36055篇
  1999年   36951篇
  1998年   65050篇
  1997年   51062篇
  1996年   42187篇
  1995年   36057篇
  1994年   33052篇
  1993年   32737篇
  1992年   27291篇
  1991年   24555篇
  1990年   24792篇
  1989年   23715篇
  1988年   22224篇
  1987年   20419篇
  1986年   19916篇
  1985年   23235篇
  1984年   22805篇
  1983年   20707篇
  1982年   19549篇
  1981年   19691篇
  1980年   18373篇
  1979年   18771篇
  1978年   18030篇
  1977年   19012篇
  1976年   22095篇
  1975年   16121篇
  1974年   15607篇
  1973年   15728篇
  1972年   13273篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
International Journal of Fracture - Adiabatic shear band (ASB) is one of the most important failure modes under high strain-rate deformation. In this work, we propose a hybrid damage model to...  相似文献   
92.
Measurement Techniques - To effectively minimize magnetic losses and increase the efficiency of machines, particularly transformers, exact separation of total losses in the magnetic cores of...  相似文献   
93.
Journal of Materials Science: Materials in Electronics - Herein, we report the synthesis of three-dimensional (3D) and one-dimensional (1D) hierarchical hematite (α-Fe2O3) nanostructures on...  相似文献   
94.
Journal of Materials Science: Materials in Electronics - Graphitic–carbon nitride (g–C3N4)-based zinc oxide (ZnO) nanocomposite (ZnO/g–C3N4) is synthesized via...  相似文献   
95.
Journal of Materials Science: Materials in Electronics - Limited light absorption and acute charge recombination on the surface of ZnO nanostructure-based photoelectrodes are the basic challenges...  相似文献   
96.
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   
97.
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   
98.

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   
99.
Li  Yashan  Mao  Jinge  Zhang  Lin  Wang  Dongbo  Shen  Si  Huang  Ying 《Scientometrics》2022,127(9):5283-5306
Scientometrics - Governments typically formulate sets of policies to guide the direction of scientific research. And the possible effects of these policies on scientific research have been...  相似文献   
100.
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   
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-23

京公网安备 11010802026262号