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   219721篇
  免费   4801篇
  国内免费   770篇
电工技术   3601篇
综合类   156篇
化学工业   37026篇
金属工艺   8589篇
机械仪表   5977篇
建筑科学   5715篇
矿业工程   964篇
能源动力   5827篇
轻工业   23847篇
水利工程   2086篇
石油天然气   3320篇
武器工业   9篇
无线电   21535篇
一般工业技术   39781篇
冶金工业   42524篇
原子能技术   4532篇
自动化技术   19803篇
  2021年   2488篇
  2020年   1766篇
  2019年   2271篇
  2018年   3555篇
  2017年   3535篇
  2016年   3764篇
  2015年   2805篇
  2014年   4242篇
  2013年   10834篇
  2012年   6929篇
  2011年   8957篇
  2010年   7067篇
  2009年   7773篇
  2008年   7637篇
  2007年   7405篇
  2006年   6233篇
  2005年   5750篇
  2004年   5457篇
  2003年   5046篇
  2002年   4938篇
  2001年   4722篇
  2000年   4489篇
  1999年   4692篇
  1998年   13265篇
  1997年   9331篇
  1996年   6935篇
  1995年   5031篇
  1994年   4239篇
  1993年   4253篇
  1992年   2851篇
  1991年   2787篇
  1990年   2605篇
  1989年   2652篇
  1988年   2573篇
  1987年   2320篇
  1986年   2218篇
  1985年   2576篇
  1984年   2331篇
  1983年   2128篇
  1982年   2026篇
  1981年   2099篇
  1980年   1970篇
  1979年   1900篇
  1978年   1869篇
  1977年   2439篇
  1976年   3393篇
  1975年   1626篇
  1974年   1603篇
  1973年   1688篇
  1972年   1382篇
排序方式: 共有10000条查询结果,搜索用时 890 毫秒
41.
Seed processing technologies are essential for seed safety and functionality through protection of physicochemical quality, pathogen inactivation, aflatoxin detoxification and alleviation of mutagenicity. Design of a pilot-scale unit of pulsed electric fields (PEF) to treat sesame seeds with respect to quality parameters, Aspergillus parasiticus inactivation and aflatoxin reduction as well as alleviation of aflatoxin mutagenicity were prompted in this study. PEF energy ranged from 0.97 to 17.28 J achieved maximum reductions of peroxide value and acidity number of 67.4 and 85.7%, respectively, and did not change color L*, a*, b* and hue values. A 60% reduction of A. parasiticus counts occurred at the maximum PEF energy. Aflatoxins G1, G2, B1, and B2 contents decreased by 94.7, 92.7, 86.9, and 98.7%, respectively. Except for the samples treated by 2.16 J with 100 μg/plate and by 6.80 J with 10 μg/plate, PEF treatment provided elimination of aflatoxin mutagenity. It is concluded that PEF treatment can be used to treat sesame seeds with preservation of physicochemical properties, inactivation of A. parasiticus and decomposition of aflatoxins with reduced mutagenicity.  相似文献   
42.
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   
43.
Neural Computing and Applications - This study presents the design of a tenth-order multiple feedback Chebyshev low-pass filter (MF-C-LPF). Component selection and gain calculation of filters are...  相似文献   
44.
45.
46.
47.
48.
49.
A layer-by-layer analysis of the structures, the phase compositions, and the defect substructures of differentially hardened rails has been carried by optical and transmission electron microscopy. It is found that the material volume of the rail head fillet is cooled faster than the volume located along the central axis.  相似文献   
50.
Lobster krill (Munida genus) represents an under‐valued crustacean frequently caught on European fishing banks. In this work, its sensory, microbiological and biochemical qualities were evaluated during chilled storage. Additionally, the effects of a prestorage antimelanosic treatment consisting of soaking in sodium metabisulphite (SMB) solutions at two different concentrations (0.25% and 0.75%) were also studied. SMB prestorage treatment provided lobster specimens that still exhibited acceptable sensory quality after 10 days of storage, while control specimens were unacceptable at that time. SMB treatment also resulted in a significant (P < 0.05) inhibition of microbial growth, mainly of Enterobacteriaceae, psychrotrophes and proteolytic bacteria. Low lipid oxidation levels were observed for all batches; however, a significantly higher (P < 0.05) retention of polyunsaturated fatty acids was found in SMB‐treated lobster, especially in the 0.75% SMB batch. The results presented here open the way to the potential commercialisation of currently under‐utilised lobster krill as a chilled product.  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