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   363篇
  免费   8篇
  国内免费   53篇
化学   67篇
力学   5篇
综合类   3篇
数学   308篇
物理学   41篇
  2023年   4篇
  2022年   3篇
  2021年   8篇
  2020年   7篇
  2019年   7篇
  2018年   10篇
  2017年   6篇
  2016年   11篇
  2015年   4篇
  2014年   19篇
  2013年   38篇
  2012年   15篇
  2011年   21篇
  2010年   14篇
  2009年   24篇
  2008年   22篇
  2007年   26篇
  2006年   33篇
  2005年   16篇
  2004年   16篇
  2003年   23篇
  2002年   15篇
  2001年   7篇
  2000年   12篇
  1999年   7篇
  1998年   18篇
  1997年   12篇
  1996年   5篇
  1995年   1篇
  1994年   2篇
  1993年   2篇
  1992年   5篇
  1988年   1篇
  1987年   2篇
  1986年   2篇
  1985年   1篇
  1984年   2篇
  1982年   1篇
  1980年   1篇
  1979年   1篇
排序方式: 共有424条查询结果,搜索用时 15 毫秒
121.
We estimate the truncation error of sampling expansions on translationinvariant spaces, generated by integer translations of a single functionand on wavelet subspaces of L 2(R). As a byproduct of themain result, we get the classical Jagerman's bound for Shannon's samplingexpansions. We also examine this error on certain wavelet sampling expansions.  相似文献   
122.
《Analytical letters》2012,45(3):177-185
Abstract

A new liquid chromatographic detector depends upon the fluorescence measurement of cerium (III) produced from the reaction of cerium (IV) with eluted reducible compounds. It is more sensitive than previous oxidative detectors by more than a factor of 100. The reaction can be varied to discriminate among compounds according to ease of oxidation.  相似文献   
123.
124.
A biosensor for ammonia solution was developed with a flavin-containing monooxygenase-3 (FMO3). The biosensor consisted of a Clark-type dissolved oxygen electrode and an FMO3 immobilized membrane. In order to amplify the biosensor output, a substrate regeneration cycle obtained by coupling the monooxygenase with L-ascorbic acid (AsA) as the reducing reagent system, was applied. The AsA 10.0?mmol?L?1 concentration was able to optimally amplify the sensor output 11 times greater. The FMO3 biosensor was used with AsA to measure ammonia solution from 3.20 to 14.29?mmol?L?1 and from 0.09 to 21.7?mmol?L?1 with 5.0 and 10.0?mmol?L?1 AsA, respectively. The FMO biosensor also had a good reproducibility such as a 2.5% coefficient of variation in eight multiple measurements, and the output current was maintained over a few hours. The selectivity of the FMO biosensor being attributed to enzyme specificity was obtained for several chemical substances (trimethyl amine, methyl mercaptan, dimethyl sulphide, and so on).  相似文献   
125.
利用辛空间上子空间构作(d,r;z]-disjunct矩阵   总被引:5,自引:5,他引:0  
一个(d,r;z]-disjunct矩阵在许多领域有着极为广泛的应用.利用辛空间上m维(m,s)型子空间的性质构作了(d,r;z]-disjunct矩阵,并利用子空间的计数定理计算了它的参数.  相似文献   
126.
《Comptes Rendus Chimie》2014,17(1):23-29
Sodium borohydride is stabilized on poly(n-butyl-4-vinylpyridinium) chloride, and it is used as an efficient and regenerable polymer-supported borohydride reagent for the reduction of a variety of carbonyl compounds, such as aldehydes, ketones, α,β-unsaturated carbonyl compounds, α-diketones, and acyloins.  相似文献   
127.
Self-bounded controlled invariant subspaces are shown to play a crucial role in the synthesis of minimal-order dynamic regulators achieving model following by output feedback with stability. The approach, completely embedded in the geometric context, provides insight into the internal eigenstructure of the minimal self-bounded invariant subspace, thus leading to an effective treatment of nonminimum-phase systems.  相似文献   
128.
A new characterization of gaps between two subspaces   总被引:5,自引:0,他引:5  
In this note, a new characterization of gaps between two subspaces of a Hilbert space is established.

  相似文献   

129.
复合算子和一类解析Toeplitz算子的约化子空间   总被引:2,自引:0,他引:2  
孙善利 《数学进展》1993,22(5):422-434
本文利用复合算子完全刻画了符号为两个Blaschke因子乘积的解析Toeplitz算子的约化子空间。  相似文献   
130.
We obtain sampling and interpolation theorems in weighted spaces of analytic functions for radial weights of arbitrary (more rapid than polynomial) growth. We give an application to invariant subspaces of arbitrary index in large weighted Bergman spaces.  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