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   86篇
  免费   3篇
  国内免费   1篇
化学   38篇
晶体学   6篇
力学   2篇
数学   11篇
物理学   33篇
  2020年   2篇
  2019年   1篇
  2018年   1篇
  2016年   5篇
  2015年   2篇
  2014年   2篇
  2013年   5篇
  2012年   1篇
  2011年   4篇
  2009年   3篇
  2008年   3篇
  2007年   7篇
  2006年   6篇
  2005年   4篇
  2004年   1篇
  2003年   4篇
  2002年   3篇
  2001年   3篇
  2000年   8篇
  1999年   3篇
  1998年   2篇
  1997年   1篇
  1994年   1篇
  1993年   1篇
  1990年   1篇
  1988年   2篇
  1987年   1篇
  1984年   1篇
  1976年   2篇
  1975年   2篇
  1974年   2篇
  1972年   1篇
  1970年   1篇
  1967年   1篇
  1961年   1篇
  1958年   1篇
  1956年   1篇
排序方式: 共有90条查询结果,搜索用时 31 毫秒
1.
This paper establishes a refinement of the classical Löwenheim-Skolem theorem. The main result shows that any first order structure has a countable elementary substructure with strong second order properties. Several consequences for Singular Cardinals Combinatorics are deduced from this.

  相似文献   

2.
Bionized nanoferrite (BNF) particles with high specific power absorption rates were synthesized in the size range of 20–100 nm by high-pressure homogenization for targeted cancer therapy with alternating magnetic fields. Several strategies were used to conjugate antibodies to the BNF particles. These strategies were compared using an immunoassay to find optimal conditions to reach a high immunoreactivity of the final antibody–particle conjugate.  相似文献   
3.
4.
The effects exhibited by adsorbed conducting polyaniline on the redox process on a molybdenum oxide surface were studied. Thermogravimetric results indicate a 4% polyaniline deposition. Cyclic voltammograms of the adsorbed polymer on MoO3 show that polyaniline exerts remarkable effects on the molybdenum blue oxidation-reduction process, with oxidation and reduction potentials of 0.33 and 0.18 V, respectively. This effect strongly enhances the electrode response, and can be used as an important tool in qualitative and/or quantitative determinations of molybdenum in solution as well as in any substrate. Copyright 1999 Academic Press.  相似文献   
5.
概述了有机波谱分析课程教学中存在的主要问题,介绍了奥尔堡PBL模式的主要特点和优势,分析了将奥尔堡PBL模式用于有机波谱分析课程教学的必要性和可行性,并从课时分配、教学内容、教学方式和考核方式等4方面提出了教学改革方案,旨在提高教学效果。  相似文献   
6.
[formula: see text] A simple synthesis of heterocyclic thiosulfonates containing indole, indoline, benzoimidazole, and quinoxaline rings is described. The synthesis of these thiosulfonates involves the preparation of the appropriately substituted thiols followed by sulfonylation to give thiosulfonates. The corresponding thiols were prepared in a simple and efficient manner by using a thiocyanation reaction either prior to heterocycle ring formation or after heterocycle ring formation. These thiosulfonates were coupled successfully to the 5,6-dihydropyran-2-one ring to give products that showed excellent HIV protease activity.  相似文献   
7.
The hydrothermal synthesis and crystal structure of the title compound is reported. The structure consists of 1-D looped chains with the HTPO ligand binding through the phosphoryl and two carboxylate oxygens to manganese atoms. The carboxylic acid group is hydrogen bonded to adjacent chains forming a 2-D hydrogen bonded network. The crystals are triclinic and the space group isP-1 with a = 11.6767(8) Å, b = 10.8680(8) Å and c = 11.4232(87rpar; Å = 92.301(2)°, = 106.932(2)° and = 103.2390(10)° V = 1341.02(16) Å3; Z = 2.  相似文献   
8.
The title compound exists as a 1D coordination polymer consisting of succinate anions, manganese cations and 2,2-bipyridyl molecules. Twelve water molecules are present in the unit cell and are part of a hydrogen bonding system. Some of these waters are binding to manganese cations while others are only participating in hydrogen bonding. The structure has a monoclinic space group P21/c with a = 8.2750(3) Å, b = 11.5104(3) Å and c = 16.9113(6) Å, = 95.2727(16); V = 1603.96(9) Å3 and Z = 4.  相似文献   
9.
10.
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