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   460701篇
  免费   6063篇
  国内免费   1209篇
电工技术   8679篇
综合类   579篇
化学工业   70788篇
金属工艺   18055篇
机械仪表   14381篇
建筑科学   10733篇
矿业工程   2320篇
能源动力   10740篇
轻工业   42889篇
水利工程   4668篇
石油天然气   8171篇
武器工业   98篇
无线电   54372篇
一般工业技术   86688篇
冶金工业   86182篇
原子能技术   10184篇
自动化技术   38446篇
  2021年   3757篇
  2019年   3657篇
  2018年   6276篇
  2017年   6275篇
  2016年   6656篇
  2015年   4207篇
  2014年   7188篇
  2013年   19825篇
  2012年   11562篇
  2011年   15737篇
  2010年   12465篇
  2009年   13932篇
  2008年   14858篇
  2007年   14912篇
  2006年   13449篇
  2005年   12060篇
  2004年   11633篇
  2003年   11325篇
  2002年   11073篇
  2001年   10945篇
  2000年   10564篇
  1999年   10570篇
  1998年   24934篇
  1997年   17753篇
  1996年   13933篇
  1995年   10861篇
  1994年   9689篇
  1993年   9463篇
  1992年   7509篇
  1991年   6979篇
  1990年   6998篇
  1989年   6663篇
  1988年   6419篇
  1987年   5613篇
  1986年   5559篇
  1985年   6421篇
  1984年   6087篇
  1983年   5486篇
  1982年   5187篇
  1981年   5377篇
  1980年   5080篇
  1979年   4905篇
  1978年   4801篇
  1977年   5484篇
  1976年   6883篇
  1975年   4340篇
  1974年   4196篇
  1973年   4344篇
  1972年   3549篇
  1971年   3299篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
To overcome the drawbacks of solid microporous materials for CO2 capture, this proof‐of‐concept study demonstrates a low‐cost and rapid method for producing composites consisting of hypercrosslinked polymers (HCP) with a polyethyleneimine (PEI) binder. The resulting materials capture CO2 through physical and chemical absorption simultaneously. Compared with HCP, the composites exhibit higher CO2 uptake, higher volumetric density, and improved tolerance to water which is attributed to the PEI binder.  相似文献   
52.
Topics in Catalysis - In this work, a simple thermal-catalytic system was used to valorize peanut shells (Arachis hypogaea), the residual biomass from the peanut industry. To accomplish this...  相似文献   
53.
Potato processing industry has a high degree of discarding, which currently has low added value being used primarily for animal feed. However, potato wastes offer a broad range of interesting components such as antioxidants, starch, protein or fibre with potential applications in the food and non-food industries. The recovery of these high valuable fractions using efficient multistage and multiproduct processes could be of great interest. This short review provides a general overview on the integral valorisation of potato wastes, offering an updated vision of the main residual parts generated during potato harvesting and processing, the high valuable obtained components focusing on the bioactive ones and the potential of the emerging extraction techniques over conventional ones. In addition, innovative applications are discussed to highlight the scientific and applied interest of these underutilised and undervalued fractions and to emphasise the integral valorisation of raw materials.  相似文献   
54.
55.
Theoretical Foundations of Chemical Engineering - New research results, as well as those published earlier by the authors, on the synthesis of azo compounds based on nitroanilines obtained by the...  相似文献   
56.
A method is proposed to generate categorical colour observer functions (individual colour matching functions) for any field size based on the CIE 2006 system of physiological observer functions. The method combines proposed categorical observer techniques of Sarkar et al with a physiologically-based individual observer model of Asano et al and a clustering technique to produce the optimal set of categorical observers. The number of required categorical observers varies depending on an application with as many as 50 required to predict individual observers' matches when a laser projector is viewed. However, 10 categorical observers are sufficient to represent colour-normal populations for personalized colour imaging. The proposed and recommended categorical observers represent a robust and inclusive technique to examine and quantify observer metamerism in any application of colorimetry.  相似文献   
57.
Polymer Bulletin - In this study, we synthesized a new ion-imprinted polymer (IIP) based on introduction of amidoxime groups in acrylonitrile, complexation with Cd2+ ions and polymerization with...  相似文献   
58.
At the hydroelectric unit No. 11 of the Nizhnekamsk hydroelectric power plant, the filling wedges of a rotor were investigated by ultrasound in the free st  相似文献   
59.
Theoretical Foundations of Chemical Engineering - The extraction of nitric and oxalic acids by neutral compounds TBP, DBBP, and TBPO have been studied. The optimal conditions of their separation...  相似文献   
60.
Journal of Communications Technology and Electronics - Abstract—The article presents a rigorous numerical solution, using the Wiener–Hopf method, to the problem of plane wave...  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