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   6795篇
  免费   443篇
  国内免费   6篇
电工技术   98篇
综合类   28篇
化学工业   1885篇
金属工艺   183篇
机械仪表   152篇
建筑科学   414篇
矿业工程   39篇
能源动力   243篇
轻工业   464篇
水利工程   41篇
石油天然气   5篇
无线电   600篇
一般工业技术   1475篇
冶金工业   278篇
原子能技术   38篇
自动化技术   1301篇
  2024年   9篇
  2023年   93篇
  2022年   100篇
  2021年   267篇
  2020年   187篇
  2019年   191篇
  2018年   190篇
  2017年   186篇
  2016年   281篇
  2015年   299篇
  2014年   349篇
  2013年   505篇
  2012年   472篇
  2011年   626篇
  2010年   411篇
  2009年   417篇
  2008年   402篇
  2007年   354篇
  2006年   275篇
  2005年   246篇
  2004年   189篇
  2003年   149篇
  2002年   149篇
  2001年   73篇
  2000年   100篇
  1999年   92篇
  1998年   83篇
  1997年   81篇
  1996年   86篇
  1995年   55篇
  1994年   46篇
  1993年   48篇
  1992年   46篇
  1991年   33篇
  1990年   20篇
  1989年   12篇
  1988年   16篇
  1987年   16篇
  1986年   12篇
  1985年   13篇
  1984年   8篇
  1983年   7篇
  1982年   4篇
  1981年   5篇
  1980年   9篇
  1976年   3篇
  1975年   4篇
  1972年   4篇
  1959年   2篇
  1954年   3篇
排序方式: 共有7244条查询结果,搜索用时 46 毫秒
991.
992.
993.
Software and Systems Modeling - Cyber-physical systems reconfigure the structure of their software architecture, e.g., to avoid hazardous situations and to optimize operational conditions like...  相似文献   
994.
995.
996.
Biopolymeric networks with plasticity show great competences in diverse fields owing to the combined biocompatible and mechanical characteristics. However, to realize such plasticity external complicated treatments, e.g., UV or organic solvent have to be applied, which in turn impair the biological nature and even mechanical properties of those systems. To address this challenge, one new type of anhydrous protein liquid crystalline (LC) gels, which exhibit flexible morphological plasticity and mechanical programmability is demonstrated. Supramolecular interactions in the smectic biogels play an important role for their high plasticity. Remarkably, the samples exhibit outstanding mechanical behaviors. The tensile strength and Young's modulus at MPa levels are comparable or even higher than chemically cross-linked hydrogels and LC elastomers. More importantly, mechanical programmability of the LC gels is achieved by genetically tuning the charge density of protein backbones. Consequently, the mechanical performance is manipulated in the range of one order of magnitude. Thus, this type of anhydrous protein LC gels offers great opportunities for load-bearing high-tech applications.  相似文献   
997.
Hydrogen diffusivity and trapping have been studied in two advanced high strength steel grades and model samples using electrochemical permeation test. Microstructures of CP1000 and DP1000 steels consist of ferrite, martensite and a small fraction of retained austenite. In addition, bainite is present in CP1000. Model phases with predominance of a particular phase have been prepared by specific heat treatment. DP1000 has shown the lowest diffusivity among all materials, while ferritic model sample has shown the highest. Differences in hydrogen diffusion coefficient values are linked to trapping microstructural characteristics and grain size.  相似文献   
998.
Zhao  Dangzhi  Strotmann  Andreas 《Scientometrics》2020,122(1):503-517
Scientometrics - The present study tests a citation counting method that filters out citations in the introductory and backgrounds sections and then weighs the remaining citations by their in-text...  相似文献   
999.
International Journal of Computer Vision - Do convolutional networks really need a fixed feed-forward structure? What if, after identifying the high-level concept of an image, a network could move...  相似文献   
1000.
Sorbicillinoids are fungal polyketides characterized by highly complex and diverse molecular structures, with considerable stereochemical intricacy combined with a high degree of oxygenation. Many sorbicillinoids possess promising biological activities. An interesting member of this natural product family is sorbicatechol A, which is reported to have antiviral activity, particularly against influenza A virus (H1N1). Through a straightforward, one-pot chemoenzymatic approach with recently developed oxidoreductase SorbC, the characteristic bicyclo[2.2.2]octane core of sorbicatechol is structurally diversified by variation of its natural 2-methoxyphenol substituent. This facilitates the preparation of a focused library of structural analogues bearing substituted aromatic systems, alkanes, heterocycles, and ethers. Fast access to this structural diversity provides an opportunity to explore the antiviral potential of the sorbicatechol family.  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