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   1484971篇
  免费   26050篇
  国内免费   6973篇
电工技术   34353篇
综合类   6373篇
化学工业   270766篇
金属工艺   64134篇
机械仪表   41919篇
建筑科学   45723篇
矿业工程   11428篇
能源动力   50268篇
轻工业   109843篇
水利工程   14912篇
石油天然气   37675篇
武器工业   134篇
无线电   196047篇
一般工业技术   280307篇
冶金工业   151712篇
原子能技术   34023篇
自动化技术   168377篇
  2021年   15578篇
  2020年   11860篇
  2019年   14614篇
  2018年   15596篇
  2017年   14886篇
  2016年   21289篇
  2015年   17391篇
  2014年   28698篇
  2013年   87982篇
  2012年   34714篇
  2011年   46970篇
  2010年   42310篇
  2009年   50839篇
  2008年   44039篇
  2007年   41183篇
  2006年   44040篇
  2005年   38920篇
  2004年   40949篇
  2003年   40841篇
  2002年   40111篇
  2001年   36620篇
  2000年   35148篇
  1999年   33981篇
  1998年   40448篇
  1997年   36811篇
  1996年   33782篇
  1995年   29878篇
  1994年   28082篇
  1993年   27965篇
  1992年   26023篇
  1991年   23074篇
  1990年   23430篇
  1989年   22572篇
  1988年   21096篇
  1987年   19301篇
  1986年   18663篇
  1985年   22015篇
  1984年   22277篇
  1983年   20245篇
  1982年   19250篇
  1981年   19346篇
  1980年   17954篇
  1979年   18471篇
  1978年   17751篇
  1977年   17473篇
  1976年   18311篇
  1975年   16034篇
  1974年   15491篇
  1973年   15581篇
  1972年   13076篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
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   
32.
33.
Metallurgical and Materials Transactions A - The influence of the chemical composition on the crystallization process, amorphous phase formation, and the anticorrosion properties of Al-Zr-Ni-Fe-Y...  相似文献   
34.
Powder Metallurgy and Metal Ceramics - The infiltration of aluminum melts into porous metal skeletons produced by powder metallurgy methods, including 3D printing, under a pressure gradient was...  相似文献   
35.
Metallurgical and Materials Transactions B - The quality requirements of aluminum products are steadily increasing, and the presence of non-metallic inclusions have a large impact on the quality of...  相似文献   
36.
37.
38.
39.
Pinhão seed is an unconventional source of starch and the pines grow up in native forests of southern Latin America. In this study, pinhão starch was adjusted at 15, 20 and 25% moisture content and heated to 100, 110 and 120 °C for 1 h. A decrease in λ max (starch/iodine complex) was observed as a result of increase in temperature and moisture content of HMT. The ratio of crystalline to amorphous phase in pinhão starch was determined via Fourier transform infra red by taking 1045/1022 band ratio. A decrease in crystallinity occurred as a result of HMT. Polarised light microscopy indicated a loss of birefringence of starch granules under 120 °C at 25% moisture content. Granule size distribution was further confirmed via scanning electron microscopy which showed the HMT effects. These results increased the understanding on molecular and structural properties of HMT pinhão starch and broadened its food and nonfood industrial applications.  相似文献   
40.
The viability and β‐galactosidase activity of four Lactobacillus strains in milk drink containing gums during 28 days of refrigerated storage at 4 °C were assessed. The population of Lactobacillus rhamnosus GGB101 and Lactobacillus rhamnosus GGB103 were maintained, whereas the population of Lactobacillus reuteri DSM20016 and Lactobacillus reuteri SD2112 significantly decreased. The recommended level of 6 log CFU g?1 was exceeded for all tested trains throughout storage. The highest viable number of Lactobacillus rhamnosus GGB103 (8.76 ± 0.03 log CFU mL?1) was obtained in the product containing carrageenan–maltodextrin. The addition of guar–locust bean–carrageenan led to 20‐fold increase in the level of β‐galactosidase activity for L. rhamnosus GGB101 (1208 ± 2.12 Miller units mL?1) compared to the control (61 ± 2.83 Miller units mL?1). Our results suggested that gums could be added to milk to improve viability and enhance β‐galactosidase activity of Lactobacillus.  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