首页 | 官方网站   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   1521757篇
  免费   27482篇
  国内免费   6969篇
工业技术   1556208篇
  2021年   14643篇
  2020年   11852篇
  2019年   14635篇
  2018年   18492篇
  2017年   18288篇
  2016年   22621篇
  2015年   17506篇
  2014年   28636篇
  2013年   87910篇
  2012年   37200篇
  2011年   51875篇
  2010年   45338篇
  2009年   53323篇
  2008年   47729篇
  2007年   45586篇
  2006年   45777篇
  2005年   41623篇
  2004年   42932篇
  2003年   42607篇
  2002年   39194篇
  2001年   35530篇
  2000年   33275篇
  1999年   32887篇
  1998年   46610篇
  1997年   39776篇
  1996年   34530篇
  1995年   31236篇
  1994年   29054篇
  1993年   28885篇
  1992年   25916篇
  1991年   23168篇
  1990年   23577篇
  1989年   22518篇
  1988年   21053篇
  1987年   19351篇
  1986年   18790篇
  1985年   22139篇
  1984年   22140篇
  1983年   20118篇
  1982年   19080篇
  1981年   19129篇
  1980年   17813篇
  1979年   18336篇
  1978年   17595篇
  1977年   17543篇
  1976年   18703篇
  1975年   15862篇
  1974年   15366篇
  1973年   15485篇
  1972年   13022篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.

ResearchGate has emerged as a popular professional network for scientists and researchers in a very short span. Similar to Google Scholar, the ResearchGate indexing uses an automatic crawling algorithm that extracts bibliographic data, citations, and other information about scholarly articles from various sources. However, it has been observed that the two platforms often show different publication and citation data for the same institutions, journals, and authors. While several previous studies analysed different aspects of ResearchGate and Google Scholar, the quantum of differences in publications, citations, and metrics between the two and the probable reasons for the same are not explored much. This article, therefore, attempts to bridge this research gap by analysing and measuring the differences in publications, citations, and different metrics of the two platforms for a large data set of highly cited authors. The results indicate that there are significantly high differences in publications and citations for the same authors captured by the two platforms, with Google Scholar having higher counts for a vast majority of the cases. The different metrics computed by the two platforms also differ in their values, showing different degrees of correlation. The coverage policy, indexing errors, author attribution mechanism, and strategy to deal with predatory publishing are found to be the main probable reasons for the differences in the two platforms.

  相似文献   
92.
Filtration Waves     
Journal of Engineering Physics and Thermophysics - Equations and relations have been obtained for describing one-dimensional filtration waves in a homogeneous isotropic porous medium in plane,...  相似文献   
93.
Journal of Engineering Physics and Thermophysics - A laminar boundary layer in a gas flow near a disk rotating at a constant angular velocity under the conditions of a significant radial...  相似文献   
94.
Journal of Engineering Physics and Thermophysics - An overview of the development of mathematical models used to describe the relationship between the parameters of the state of real gases is...  相似文献   
95.
Kulemin  V. V.  Martynov  K. V.  Krasavina  E. P.  Rumer  I. A.  Kulyukhin  S. A. 《Radiochemistry》2022,64(2):158-163
Radiochemistry - The distribution of uranium between different phases of cast stone matrices fabricated by fusion of basalt and uranium-bearing SiO2-based collectors was investigated. It was found...  相似文献   
96.
Savruk  M. P.  Kravets  V. S.  Chornenkyi  A. B. 《Materials Science》2022,57(4):492-501
Materials Science - We develop an analytic-numerical algorithm for the determination of the optimal shape of smooth holes (with minimum stress concentration) in quasiorthotropic plates subjected to...  相似文献   
97.
Journal of Engineering Physics and Thermophysics - The possibility of intensifying the drying of materials by noncontact ultrasonic action at a frequency of 22 kHz at sound pressure levels up to...  相似文献   
98.
Yakunin  S. A. 《Radiochemistry》2022,64(4):482-490
Radiochemistry - As applied to the radioactive waste vitrification technology, published data on the behavior of cesium and its release into the gas phase are reviewed. The volatility of cesium...  相似文献   
99.
The aim of this study was to determine the effects of tumbling at different post-mortem times on the proteolytic features and quality attributes of beef loins (M. longissimus lumborum). Loins (n = 12) were cut into 4 sections and assigned to tumbling at 1, 6 or 11 days post-mortem or non-tumbled control. Upon tumbling, additional ageing was applied to a common post-mortem time of 16 days. In general, tumbling had no considerable impacts on water-holding ability of samples. Tumbling resulted in an immediate decrease in shear force values (WBSF) of beef samples. Tumbling at 1 day post-mortem with no ageing had similar WBSF compared to the non-tumbled controls at 16 days (P > 0.05). With ageing, tumbling increased amounts of protein degradation, myofibrillar fragmentation and calpain-1 autolysis of samples. These results suggest that early post-mortem tumbling coupled with ageing can synergistically impact the tenderness development of beef loins and shorten the necessary ageing period.  相似文献   
100.
Rapid digestion and absorption of carbohydrates have become a health issue (high glycaemic index, GI), which can be a matter of greater concern when consumed in large quantities. Depending upon the influence of carbohydrates on the blood sugar levels, GI classifies carbohydrates (on a scale of 100) as low (<55), medium (55–70) and high (>70) GI foods. Among the pseudocereals, chia seed possesses relatively lower GI (28.53), as compared to buckwheat (52.35), amaranth (47.65) and quinoa (61.50). Consumers now prefer foods with a high GI over the ones with low GI to prevent various metabolic alterations. Celiac disease is a lifelong disorder prevalent worldwide and can only be controlled by following a strict lifelong gluten-free diet. Therefore, pseudocereals could be a potential alternate for low GI food and developing gluten-free food products, including bread, cookies, noodles and pasta. This review synthesises the recently published literatures on pseudocereals as a lowering GI and healthy food option. This review also gives insights into developing pseudocereals as a potential and novel ingredient for gluten-free food applications and the latest research conducted worldwide.  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-23

京公网安备 11010802026262号