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   780篇
  免费   22篇
  国内免费   3篇
化学   551篇
晶体学   5篇
力学   10篇
数学   150篇
物理学   89篇
  2021年   4篇
  2020年   8篇
  2019年   11篇
  2018年   10篇
  2017年   7篇
  2016年   25篇
  2015年   20篇
  2014年   13篇
  2013年   27篇
  2012年   32篇
  2011年   39篇
  2010年   39篇
  2009年   19篇
  2008年   50篇
  2007年   54篇
  2006年   55篇
  2005年   43篇
  2004年   28篇
  2003年   31篇
  2002年   23篇
  2001年   11篇
  2000年   15篇
  1999年   5篇
  1998年   7篇
  1997年   10篇
  1996年   11篇
  1993年   7篇
  1992年   9篇
  1991年   9篇
  1990年   4篇
  1989年   7篇
  1988年   5篇
  1984年   10篇
  1983年   9篇
  1982年   14篇
  1981年   7篇
  1980年   10篇
  1979年   10篇
  1978年   10篇
  1977年   8篇
  1976年   4篇
  1975年   6篇
  1974年   13篇
  1973年   11篇
  1972年   5篇
  1970年   7篇
  1968年   4篇
  1964年   5篇
  1961年   3篇
  1959年   3篇
排序方式: 共有805条查询结果,搜索用时 921 毫秒
801.
802.
Currently laboratory automation is a rapidly growing field of interest in chemical process research and development. The idea of using automated and parallel methods for the optimization of chemical processes was initiated by the extensive implementation of combinatorial techniques in medicinal chemistry. The techniques applied involve all methods and concepts aimed at dramatically increasing the output of research by extensive use of automation, parallelization and miniaturization, fast analysis, advanced data handling and by efficient automated planning, scheduling and tracking. In this paper, the “Combi” or high‐throughput experimentation approach consists of the integration of parallel experimentation with four key modeling and simulation methodologies, modeling, multivariate statistics, statistical design of experimentation and empirical model generation.

Integrated automated liquid and solid handling.  相似文献   

803.
The tensile deformation behaviour of poly(1-butene) and two of its ethylene copoloymers was studied at room temperature. This was done by investigating true stress-strain curves at constant strain rates, elastic recovery and stress relaxation properties and in-situ WAXS patterns during the deformation process. As for a series of semicrystalline polymers in previous studies, a strain-controlled deformation behaviour was found. The differential compliance, the recovery properties and the stress relaxation curves changed simultaneously at well-defined points. The strains at which these points occurred along the true stress-strain remained constant for the different samples despite their different percentage crystallinities. The well-defined way in which the different samples respond to external stresses complies with the granular substructure of the crystalline lamellae in a semicrystalline polymer.  相似文献   
804.
805.
Fucose is a signaling carbohydrate that is attached at the end of glycan processing. It is involved in a range of processes, such as the selectin-dependent leukocyte adhesion or pathogen-receptor interactions. Mass-spectrometric techniques, which are commonly used to determine the structure of glycans, frequently show fucose-containing chimeric fragments that obfuscate the analysis. The rearrangement leading to these fragments—often referred to as fucose migration—has been known for more than 25 years, but the chemical identity of the rearrangement product remains unclear. In this work, we combine ion-mobility spectrometry, radical-directed dissociation mass spectrometry, cryogenic IR spectroscopy of ions, and density-functional theory calculations to deduce the product of the rearrangement in the model trisaccharides Lewis x and blood group H2. The structural search yields the fucose moiety attached to the galactose with an α(1→6) glycosidic bond as the most likely 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