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   1490077篇
  免费   27598篇
  国内免费   6908篇
电工技术   33694篇
综合类   6467篇
化学工业   254798篇
金属工艺   63567篇
机械仪表   42038篇
建筑科学   43813篇
矿业工程   11350篇
能源动力   49763篇
轻工业   114291篇
水利工程   15361篇
石油天然气   36295篇
武器工业   136篇
无线电   195121篇
一般工业技术   284177篇
冶金工业   170331篇
原子能技术   33790篇
自动化技术   169591篇
  2021年   14571篇
  2020年   11829篇
  2019年   14607篇
  2018年   14839篇
  2017年   14034篇
  2016年   21048篇
  2015年   17358篇
  2014年   28764篇
  2013年   87871篇
  2012年   36166篇
  2011年   48445篇
  2010年   42198篇
  2009年   50359篇
  2008年   45356篇
  2007年   42587篇
  2006年   45603篇
  2005年   39878篇
  2004年   42437篇
  2003年   41591篇
  2002年   39103篇
  2001年   35932篇
  2000年   33595篇
  1999年   33055篇
  1998年   44385篇
  1997年   38414篇
  1996年   33852篇
  1995年   30991篇
  1994年   29041篇
  1993年   28586篇
  1992年   26010篇
  1991年   23191篇
  1990年   23498篇
  1989年   22428篇
  1988年   20958篇
  1987年   19284篇
  1986年   18827篇
  1985年   22212篇
  1984年   22343篇
  1983年   20208篇
  1982年   19119篇
  1981年   19162篇
  1980年   17812篇
  1979年   18469篇
  1978年   17677篇
  1977年   17732篇
  1976年   19280篇
  1975年   15881篇
  1974年   15445篇
  1973年   15522篇
  1972年   13084篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Traditional West African pearl millet couscous products are popular; however, their preparation is laborious, time-consuming and energy-demanding, involving agglomeration, steaming, drying and sieving steps. In this study, a process was developed to produce millet couscous using a high pressure, high temperature and low-cost single-screw extruder. The innovation was to directly process the cooked low-moisture extrudate to a couscous product by drying and milling to the appropriate particle size (ranging between 1 and 2 mm). Throughput for the traditional process as prepared for commercial sale is 50 kg per day, but with the same amount of labour, the extrusion process yields ~350 kg per day. A consumer sensory study held in Niamey (Niger) showed that the extruded millet couscous was comparable to traditional couscous, though this was dependent on selection of the proper millet variety. This novel extrusion process could stimulate small- to medium-scale manufacturing of couscous and couscous-type products in West Africa.  相似文献   
62.
Food- and waterborne viruses, such as human norovirus, hepatitis A virus, hepatitis E virus, rotaviruses, astroviruses, adenoviruses, and enteroviruses, are major contributors to all foodborne illnesses. Their small size, structure, and ability to clump and attach to inanimate surfaces make viruses challenging to reduce or eliminate, especially in the presence of inorganic or organic soils. Besides traditional wet and dry methods of disinfection using chemicals and heat, emerging physical nonthermal decontamination techniques (irradiation, ultraviolet, pulsed light, high hydrostatic pressure, cold atmospheric plasma, and pulsed electric field), novel virucidal surfaces, and bioactive compounds are examined for their potential to inactivate viruses on the surfaces of foods or food contact surfaces (tools, equipment, hands, etc.). Every disinfection technique is discussed based on its efficiency against viruses, specific advantages and disadvantages, and limitations. Structure, genomic organization, and molecular biology of different virus strains are reviewed, as they are key in determining these techniques effectiveness in controlling all or specific foodborne viruses. Selecting suitable viral decontamination techniques requires that their antiviral mechanism of action and ability to reduce virus infectivity must be taken into consideration. Furthermore, details about critical treatments parameters essential to control foodborne viruses in a food production environment are discussed, as they are also determinative in defining best disinfection and hygiene practices preventing viral infection after consuming a food product.  相似文献   
63.
Cybernetics and Systems Analysis - The authors propose a new method for finding the sum of two or more multidigit values in a parallel computational model. The method reduces finding the sum of a...  相似文献   
64.
Compositional analysis of boron carbide on nanometer length scales to examine or interpret atomic mechanisms, for example, solid-state amorphization or grain-boundary segregation, is challenging. This work reviews advancements in high-resolution microanalysis to characterize multiple generations of boron carbide. First, ζ-factor microanalysis will be introduced as a powerful (scanning) transmission electron microscopy ((S)TEM) analytical framework to accurately characterize boron carbide. Three case studies involving the application of ζ-factor microanalysis will then be presented: (1) accurate stoichiometry determination of B-doped boron carbide using ζ-factor microanalysis and electron energy loss spectroscopy, (2) normalized quantification of silicon grain-boundary segregation in Si-doped boron carbide, and (3) calibration of a scanning electron microscope X-ray energy-dispersive spectroscopy (XEDS) system to measure compositional homogeneity differences of B/Si-doped arc-melted boron carbides in the as-melted and annealed conditions. Overall, the improvement and application of advanced analytical tools have helped better understand processing–microstructure–property relationships and successfully manufacture high-performance ceramics.  相似文献   
65.
Journal of Applied Electrochemistry - Organic corrosion inhibitors have become competent alternatives to hazardous chrome conversion coatings due to their rapid adsorption over metal surfaces in...  相似文献   
66.
Russian Engineering Research - Systems are considered for the dehydration of petroleum so as to separate water–petroleum emulsions. In particular, the low-temperature microwave (UHF)...  相似文献   
67.
Wireless Personal Communications - Nowadays, Wireless Sensor Networks (WSNs) is enhancing for different applications. Simultaneously, energy consumption for processing the tasks in most of the...  相似文献   
68.
Journal of Engineering Physics and Thermophysics - A simulation of the vibroacoustic processes proceeding in a long pipe with an obstacle in the form of a circular cylinder, in which a fluid flows,...  相似文献   
69.
Lyzlova  E. V.  Glukhova  A. V.  Konnikov  A. V.  Dyug  K. O. 《Radiochemistry》2022,64(2):176-182
Radiochemistry - The sorption extraction of Pu and Am from nitric acid simulation solutions were studied on a solid extractant (TVEX) AXIONIT MND 40T in a static mode. It is shown that the...  相似文献   
70.
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