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   1038281篇
  免费   15336篇
  国内免费   3155篇
电工技术   18944篇
综合类   1015篇
化学工业   156233篇
金属工艺   38543篇
机械仪表   30660篇
建筑科学   25899篇
矿业工程   4512篇
能源动力   28406篇
轻工业   88052篇
水利工程   9817篇
石油天然气   15509篇
武器工业   60篇
无线电   122374篇
一般工业技术   198746篇
冶金工业   205165篇
原子能技术   19293篇
自动化技术   93544篇
  2021年   8828篇
  2020年   6634篇
  2019年   8280篇
  2018年   13870篇
  2017年   13717篇
  2016年   14686篇
  2015年   10270篇
  2014年   16729篇
  2013年   49394篇
  2012年   26992篇
  2011年   37592篇
  2010年   29599篇
  2009年   33439篇
  2008年   34458篇
  2007年   34279篇
  2006年   30435篇
  2005年   27636篇
  2004年   26685篇
  2003年   26419篇
  2002年   25148篇
  2001年   24851篇
  2000年   23205篇
  1999年   24816篇
  1998年   62576篇
  1997年   44407篇
  1996年   34344篇
  1995年   26067篇
  1994年   22888篇
  1993年   22640篇
  1992年   16263篇
  1991年   15373篇
  1990年   15078篇
  1989年   14569篇
  1988年   13736篇
  1987年   12146篇
  1986年   11914篇
  1985年   13732篇
  1984年   12725篇
  1983年   11358篇
  1982年   10553篇
  1981年   10701篇
  1980年   10055篇
  1979年   9805篇
  1978年   9461篇
  1977年   11351篇
  1976年   15234篇
  1975年   8148篇
  1974年   7736篇
  1973年   7765篇
  1972年   6379篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
Vieira  Elizabeth S. 《Scientometrics》2022,127(5):2747-2772

It is widely recognised that science in Africa will benefit from international research collaboration (IRC), and therefore studies have been done on IRC in Africa (hereafter: Africa-related IRC research). However, there is no information on the development of Africa-related IRC research, the geographical location of the scientists interested in the topic, the visibility of the literature and the themes researched. This information makes it possible to understand relevant aspects in the context of IRC in Africa, which are useful for identifying IRC strengths, weaknesses and opportunities. It also allows paving the way for future research on this topic. Using discipline–specific terms, bibliometric, and thematic analysis, I collected the literature on Africa-related IRC research indexed in the Web of Science Core Collection (WoS). The results showed that the number of publications on the topic has increased, few African countries have researched the topic, a third of the publications were written exclusively by African scientists, and the topic has high visibility. The panoply of publications revealed that patterns, driving factors, effects, networks, asymmetries, and policies concerning IRC were the main themes researched.

  相似文献   
72.
Marrone  Mauricio  Lemke  Sascha  Kolbe  Lutz M. 《Scientometrics》2022,127(7):3857-3878
Scientometrics - Computer-assisted methods and tools can help researchers automate the coding process of literature reviews and accelerate the literature review process. However, existing...  相似文献   
73.
Journal of Materials Science: Materials in Electronics - Nano Mn0.95M0.05S (M ≡ Cu, Mg) samples were produced using molten salt solid state reaction method. Rietveld analysis of X-ray...  相似文献   
74.
Chemical and Petroleum Engineering - The hydrodynamics of oxidation towers used for bitumen production were studied using a model tower having transparent walls. Experiments were carried out in two...  相似文献   
75.
Journal of Engineering Physics and Thermophysics - A numerical investigation has been made into the interaction of slender (5–20 calibers) steel cylinder strikers with orthotropic compost...  相似文献   
76.
Journal of Engineering Physics and Thermophysics - Results of investigation into the influence of a corrosion process on thermotechnical characteristics of heat pipes of low-temperature range are...  相似文献   
77.
Deshmukh  P.  Sar  S. K.  Smječanin  N.  Nuhanović  M.  Lalwani  R. 《Radiochemistry》2022,64(4):532-542
Radiochemistry - Magnetically modified waste bark of the Aegle marmelos tree was prepared by using green synthesis method and was used in a batch system for U(VI) removal from aqueous solution. The...  相似文献   
78.
Kamar  M. S.  Shalan  A. S.  Youssef  W. M.  Hussein  A. E. M.  Khawassek  Y. M.  Taha  M. H. 《Radiochemistry》2022,64(2):244-256
Radiochemistry - Ferrugination, sericitization, desulfitization, chloritization, and kaolinitization of hydrothermal origin are the main wall rock alterations occurring within the NNW shear zones...  相似文献   
79.

Modern metrics for evaluating agreement coefficients between the experimental results and expert opinion are compared, and the possibility of using these metrics in experimental research in automatic text processing by machine learning methods is assessed. The choice of Cohen’s kappa coefficient as a measure of expert opinion agreement in the NLP and Text Mining problems is justified. An example of using Cohen’s kappa coefficient for evaluating the level of agreement between the opinion of an expert and the results of ML classification and the measure of agreement of expert opinions in the alignment of sentences of the Kazakh-Russian parallel corpus is given. Based on this analysis, it is proved that Cohen’s kappa coefficient is one of the best statistical methods for determining the level of agreement in experimental studies due to its ease of use, computing simplicity, and high accuracy of the results.

  相似文献   
80.
Wireless Personal Communications - Multiple inputs multiple outputs (MIMO) is a reliable technique which can manage the increased wireless data traffic in the future generation of wireless...  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