首页 | 官方网站   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   301篇
  免费   0篇
数理化   301篇
  2021年   5篇
  2020年   4篇
  2019年   6篇
  2018年   7篇
  2017年   7篇
  2016年   9篇
  2015年   3篇
  2014年   5篇
  2013年   6篇
  2012年   15篇
  2010年   9篇
  2009年   9篇
  2008年   4篇
  2007年   11篇
  2006年   5篇
  2005年   6篇
  2004年   7篇
  2003年   7篇
  2002年   6篇
  2001年   5篇
  2000年   4篇
  1999年   3篇
  1998年   5篇
  1994年   4篇
  1993年   4篇
  1992年   4篇
  1991年   7篇
  1990年   5篇
  1989年   3篇
  1988年   8篇
  1987年   4篇
  1984年   5篇
  1983年   5篇
  1982年   3篇
  1981年   4篇
  1980年   3篇
  1978年   3篇
  1977年   5篇
  1976年   3篇
  1975年   6篇
  1974年   9篇
  1973年   11篇
  1972年   5篇
  1971年   6篇
  1969年   3篇
  1968年   4篇
  1967年   9篇
  1966年   5篇
  1961年   2篇
  1960年   2篇
排序方式: 共有301条查询结果,搜索用时 46 毫秒
1.
General Relativity and Gravitation - In previous work, we established theoretical results concerning the effect of matter shells surrounding a gravitational wave (GW) source, and we now apply these...  相似文献   
2.
Polymeric derivatives of dammarane triterpenoids with both labile and strong (covalent) polymer-triterpenoid bonds were prepared from N-vinylpyrrolidone copolymers.  相似文献   
3.
The order-disorder phase transition in vanadium monoxide of substoichiometric compositions VOy has been studied for the first time in situ by the Faraday method with a pendulum magnetic balance of the Domenically type. A minimum is found on the temperature dependence of the magnetic susceptibility of vanadium monoxide of different compositions at a temperature of about 700 K. X-ray diffraction analysis performed before and after measuring the magnetic susceptibility confirmed the change in the structure of vanadium monoxide and the possibility of atom-vacancy processes upon cooling and heating of the samples.  相似文献   
4.
5.
A butylamine derivative of fullerene was prepared by the reaction of butylamine with fullerene C60. The experimental electrooptical and dipole characteristics of the derivative were compared with the corresponding calculated PM3 data. The reaction product proved to be inhomogeneous in the number of the amine molecules added; it contains polar multiadducts of C60 with noncentrosymmetric distribution of covalently bound amino groups over the fullerene core.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 5, 2005, pp. 795–802.Original Russian Text Copyright © 2005 by Evlampieva, Yakimanskii, Dobrodumov, Nazarova, Pashkov, Panarin, Ryumtsev.  相似文献   
6.
On the basis of a study of the vibrational spectra in the solid state of the product of the reaction of 2-cyanophenyl isocyanate with hydroxylamine and its isotopic analogs (15N O and 15NH2) it was demonstrated that the compound obtained has the 4-amino-1H-quinazolin-2-one 3-oxide structure.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 968–972, July, 1981.  相似文献   
7.
The compositions of the lipids and fatty acids of the seeds ofCynoglossum officinale, familyBoraginaceae have been established. The bulk of the lipids consisted of netural compounds (95.2%), while the amounts of glycolipids and phospholipids were 3.1 and 1.7%, respectively. Among the fatty acids, in addition to the usual components, acids characteristic for theBoraginaceae family have been found: 18:3 (6, 9, 12), 18:3 (9, 12, 15), 18:4 (6, 9, 12, 15), 20:1 (11), 22:1 (13), and 24:1 (15). Institute of the Chemistry of Plant Substances, Uzbek Academy of Sciences, Tashkent. South Urals Reservation, Bashkir. Institute of Chemistry, Bashkir Scientific-Center, Urals Branch, Russian Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 758–762, November–December, 1991.  相似文献   
8.
By the peptide map method, a phosphorylated peptide has been isolated from a tryptic hydrolysate of phosphorylated yeast inorganic pyrophosphatase (I), and this is a direct proof of the formation of a covalent bond between (I) and phosphate in the course of this reaction. The isolation and analysis of the peptide from the tryptic hydrolysate shows that the phosphate acceptor is probably the aspartic acid residue 240 or 248. Analysis of a tryptic hydrolysate of (I) modified with O-phosphoethanolamine has shown that O-phosphoethanolamine forms an amide bond with the carboxy group of the same aspartic acid residue. In an alkaline medium, the phosphate residue migrates to the imidazole ring of a histidine residue, apparently that present in position 222.  相似文献   
9.
A study has been made of the gossypol pigments of the seeds and roots of a cotton plant of the variety Tashkent-1 infected with wilt in comparison with a healthy plant. The amount of gossypol in the infected plant was lower than in the healthy plant. In the diseased plant, gossypurpurin was concentrated in the roots, and in the healthy plant it was concentrated in the seeds. Gossypol possessing optical activity was detected in the seeds and roots of both the healthy and the diseased plants.Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 63–66, January–February, 1989.  相似文献   
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-23

京公网安备 11010802026262号