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   95篇
  免费   0篇
  国内免费   2篇
化学   39篇
力学   5篇
数学   29篇
物理学   24篇
  2023年   1篇
  2020年   3篇
  2019年   1篇
  2017年   1篇
  2015年   1篇
  2014年   2篇
  2013年   7篇
  2012年   1篇
  2011年   4篇
  2010年   4篇
  2009年   4篇
  2008年   1篇
  2007年   2篇
  2006年   5篇
  2005年   4篇
  2004年   6篇
  2002年   2篇
  2001年   3篇
  2000年   4篇
  1999年   2篇
  1998年   1篇
  1997年   4篇
  1996年   2篇
  1995年   1篇
  1992年   2篇
  1991年   1篇
  1989年   1篇
  1986年   3篇
  1985年   1篇
  1984年   3篇
  1982年   1篇
  1981年   6篇
  1980年   1篇
  1979年   1篇
  1976年   2篇
  1975年   1篇
  1973年   4篇
  1972年   1篇
  1971年   2篇
  1968年   1篇
排序方式: 共有97条查询结果,搜索用时 15 毫秒
31.
A collection of about 300 microbes was surveyed for the ability to generate chiral secondary alcohols by enantioselective reduction of a series of alkyl aryl ketones. Microbial cultures demonstrating utility in reducing model ketones were arrayed in multi-well plates and used to rapidly identify specific organisms capable of producing chiral alcohols used as intermediates in the synthesis of several drug candidates. Approximately 60 cultures were shown to selectively reduce various ketones providing both the R and S enantiomers of the corresponding alcohols in 92-99% ee with yields up to 95% at 1-4 g/L. An alternative approach to chiral alcohols based on selective microbial oxidation of racemic alcohols is also reported. This study provides a useful reference for generating chiral alcohols by selective microbial bioconversion.  相似文献   
32.
We prove a weak-type estimate for the absolute value mapping in the preduals of semifinite factors which extends an earlier result of Kosaki for the trace class.Research supported by the Australian Research Council (ARC) and the Netherlands Organization for Scientific Research (NWO)  相似文献   
33.
In this paper Jeffery–Hamel flow has been studied and its nonlinear ordinary differential equation has been solved through homotopy analysis method (HAM). The obtained solution in comparison with the numerical ones represents a remarkable accuracy. The results also indicate that HAM can provide us with a convenient way to control and adjust the convergence region.  相似文献   
34.
Explicit forms for the concomitants which are bilinear in two spinors of type [3/2, 1/2] and the concomitants which are quadratic in a single spinor of type [3/2, 1/2] are obtained. The dual-tensors, where they exist, are also given.The concomitants of higher-order spinors can be obtained in an exactly similar manner.  相似文献   
35.
We study actions of the Vilenkin group k=0 m(k) onL p -spaces associated with a semi-finite von Neumann algebra , via a generalized triangular truncation operator. The systems of eigenspaces that arise contain the classical unbounded Vilenkin systems and we show that such systems with the inverse lexicographic enumeration form Schauder decompositions in all reflexive non-commutativeL p -spaces. This is a non-commutative analogue of a theorem of Paley for unbounded Vilenkin systems, which in the classical setting is due to W.S. Young, F. Schipp and P. Simon.Research is partially supported by the NSF Grant DMS 99-71587Research is partially supported by the Australian Research Council (ARC)  相似文献   
36.
We describe here a new strategy for the synthesis of polymers with highly branched architectures. The strategy involves the synthesis by anionic polymerization of well-defined AB2 polystyrene macromonomers with molecular weights from 3,600 to 94,000 gmol−1, which are then converted via a one-pot polycondensation reaction into high molecular weight, long-chain (hyper)branched architectures. Since the Hyperbranched structures are built up from condensation Macromonomers we have coined the term ‘HyperMac’ to describe these branched polymers. In this paper we report the synthesis of the HyperMacs, the optimal conditions for the polycondensation reaction and some preliminary characterization studies.  相似文献   
37.
The range and utility of DABAL-Me3 couplings of methyl esters and free carboxylic acids with primary and secondary amines under a variety of conditions (reflux, sealed tube, microwave) has been compared for a significant range of coupling partners of relevance to the preparation of amides of interest in pharmaceutical chemistry. Commercial microwave reactors promote the fastest couplings and allow the use of significantly sterically hindered amines (primary and secondary) and carboxylic acids derivatives. The influence of microwave energy on the reaction system was shown to be typically related to thermal effects (over-pressuring and superheating).  相似文献   
38.

Background  

Soy-derived isoflavones potentially protect against obesity and depression. In five different studies we examined the influence of soy-containing diets or equol injections on depression, serotonin levels, body weight gain (BW) and white adipose tissue (WAT) deposition in female Long-Evans rats at various stages of life [rats were intact, ovariectomized or experienced natural ovarian failure (NOF)].  相似文献   
39.
Fully symmetric operator spaces   总被引:4,自引:0,他引:4  
It is shown that certain interpolation theorems for non-commutative symmetric operator spaces can be deduced from their commutative versions. A principal tool is a refinement of the notion of Schmidt decomposition of a measurable operator affiliated with a given semi-finite von Neumann algebra.Research supported by A.R.C.  相似文献   
40.
Non-commutative Banach function spaces   总被引:7,自引:0,他引:7  
Dedicated to A.C. Zaanen on the occasion of his 75th birthday  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