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   657篇
  免费   11篇
  国内免费   12篇
化学   300篇
力学   5篇
数学   208篇
物理学   167篇
  2020年   5篇
  2019年   5篇
  2018年   6篇
  2017年   7篇
  2016年   7篇
  2015年   15篇
  2014年   16篇
  2013年   20篇
  2012年   14篇
  2011年   31篇
  2010年   9篇
  2009年   10篇
  2008年   25篇
  2007年   27篇
  2006年   26篇
  2005年   17篇
  2004年   20篇
  2003年   26篇
  2002年   20篇
  2001年   8篇
  2000年   14篇
  1999年   17篇
  1998年   10篇
  1997年   6篇
  1996年   8篇
  1995年   6篇
  1994年   7篇
  1993年   9篇
  1992年   7篇
  1991年   14篇
  1990年   10篇
  1989年   11篇
  1988年   14篇
  1987年   13篇
  1986年   13篇
  1985年   18篇
  1984年   12篇
  1983年   9篇
  1982年   7篇
  1981年   19篇
  1980年   23篇
  1979年   11篇
  1978年   15篇
  1977年   13篇
  1976年   15篇
  1975年   5篇
  1974年   5篇
  1971年   5篇
  1970年   5篇
  1969年   6篇
排序方式: 共有680条查询结果,搜索用时 15 毫秒
1.
We prove a non-vanishing result in weight aspect for the product of two Fourier coefficients of a Hecke eigenform of half-integral weight.  相似文献   
2.
We study the interpolation of Morrey-Campanato spaces and some smoothness spaces based on Morrey spaces, e. g., Besov-type and Triebel-Lizorkin-type spaces. Various interpolation methods, including the complex method, the ±-method and the Peetre-Gagliardo method, are studied in such a framework. Special emphasis is given to the quasi-Banach case and to the interpolation property.  相似文献   
3.
4.
Flavonoids are a large group of plant secondary metabolites with a variety of biological properties and are therefore of interest to many scientists, as they can lead to industrially interesting intermediates. The anaerobic gut bacterium Eubacterium ramulus can catabolize flavonoids, but until now, the pathway has not been experimentally confirmed. In the present work, a chalcone isomerase (CHI) and an enoate reductase (ERED) could be identified through whole genome sequencing and gene motif search. These two enzymes were successfully cloned and expressed in Escherichia coli in their active form, even under aerobic conditions. The catabolic pathway of E. ramulus was confirmed by biotransformations of flavanones into dihydrochalcones. The engineered E. coli strain that expresses both enzymes was used for the conversion of several flavanones, underlining the applicability of this biocatalytic cascade reaction.  相似文献   
5.
We will give a new proof for the fact that the values of Dedekind sums are dense on the real line.  相似文献   
6.
Mitochondrial membrane potential is more negative in cancer cells than in normal cells, allowing cancer targeting by delocalized lipophilic cations (DLCs). However, as the difference is rather small, these drugs affect also normal cells. Now a concept of pro‐DLCs is proposed based on an N‐alkylaminoferrocene structure. These prodrugs are activated by the reaction with reactive oxygen species (ROS) forming ferrocenium‐based DLCs. Since ROS are overproduced in cancer, the high‐efficiency cancer‐cell‐specific targeting of mitochondria could be achieved as demonstrated by fluorescence microscopy in combination with two fluorogenic pro‐DLCs in vitro and in vivo. We prepared a conjugate of another pro‐DLC with a clinically approved drug carboplatin and confirmed that its accumulation in mitochondria was higher than that of the free drug. This was reflected in the substantially higher anticancer effect of the conjugate.  相似文献   
7.
8.
9.
The application of optimal control theory to minimum weight design of continuous one-dimensional structural elements subject to eigenvalue constraints is discussed. If not only the value of an eigenvalue is prescribed but also its position in the sequence of the ordered eigenvalues—for example, the critical buckling load of a column—the corresponding optimal control problem is shown to include necessarily all eigenvalues. Considering the unspecified eigenvalues as free parameters, necessary conditions for minimum weight design are derived. These conditions are compared with those obtained by use of variational methods. Attention is focused on the special case of multimodal solutions.  相似文献   
10.
Abstract

Nucleophilic C-S bond cleavage of Sulfonediimines to Sulfinamidine-type Structures is discussed  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