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   423篇
  免费   15篇
  2022年   6篇
  2021年   7篇
  2020年   4篇
  2019年   4篇
  2018年   13篇
  2017年   11篇
  2016年   8篇
  2015年   4篇
  2014年   13篇
  2013年   15篇
  2012年   14篇
  2011年   16篇
  2010年   15篇
  2009年   12篇
  2008年   15篇
  2007年   21篇
  2006年   20篇
  2005年   20篇
  2004年   16篇
  2003年   26篇
  2002年   19篇
  2001年   18篇
  2000年   12篇
  1999年   9篇
  1998年   10篇
  1996年   4篇
  1995年   3篇
  1994年   4篇
  1992年   7篇
  1991年   5篇
  1990年   3篇
  1989年   6篇
  1988年   5篇
  1986年   11篇
  1985年   4篇
  1984年   3篇
  1983年   5篇
  1982年   2篇
  1980年   4篇
  1979年   4篇
  1978年   2篇
  1977年   3篇
  1976年   3篇
  1975年   2篇
  1974年   4篇
  1973年   5篇
  1972年   2篇
  1969年   3篇
  1967年   3篇
  1966年   3篇
排序方式: 共有438条查询结果,搜索用时 15 毫秒
1.
Naumova  E. V.  Vladimirov  Yu. A.  Beloussov  L. V.  Tuchin  V. V.  Volodyaev  I. V. 《Biophysics》2021,66(5):764-778
Biophysics - This review is devoted to the methods for studying the ultraweak luminescence of biological objects; in addition to modern methods aimed at studies in the visible, near-infrared, and...  相似文献   
2.
PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4+ and CD8+ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.  相似文献   
3.
Lipoteichoic acid (LTA) of group A streptococci, type M 29 was studied. Chemical and 13C NMR spectroscopic analysis showed that the polymer contained poly(glycerophosphate) chain consisting of 12-14 glycerophosphate elements united by the 1----3 type phosphodiether bond and diglucosylglyceride. Oleic, stearic, palmitic and palmitoleic fatty acids predominated in the polymer composition. The content of the fatty acids amounted approximately to 2 per cent of LTA dry weight. The poly(glycerophosphate) chain contained 6-7 ether linked alanyl moieties. The results of the LTA biological study were analyzed in comparison to the data on a previous study of antitumor and cardiotoxic properties of teichoic acid from Streptomyces levoris K-3053 which is structurally close to the LTA hydrophilic moiety. It was assumed that the molecule negative charge had an effect on the cardiotoxic and antitumor activity.  相似文献   
4.
Two hypotheses are capable of explaining nonrandom loss of one parent's alleles at tumor suppressor loci in sporadic cases of several pediatric cancers, including retinoblastoma—namely, preferential germ-line mutation or chromosome imprinting. We have examined 74 cases of sporadic retinoblastoma for tumors in which at least two genetic events—loss of heterozygosity for chromosome 13q markers and formation of an isochromosome 6p—have occurred. Sixteen cases were found to contain both events. In 13 of 16 such tumors, the chromosomes 13q that were lost and chromosomes 6p that were duplicated are derived from the same parent. These data may be explained within the framework of the genome imprinting model but are not predicted by preferential germ-line mutation.  相似文献   
5.
6.
The cell-wall teichoic acids of Nocardiopsis dassonvillei IMRU 509T, IMRU 504 and IMRU 1250 and Nocardiopsis antarctius VKM Ac-836T have the same unique structure that has not heretofore been found in bacteria. The polymer is built of 10 to 13 repeating units:
  相似文献   
7.
Mammalian Genome - Several lines of evidence suggest that the presence of the Y chromosome influences DNA methylation of autosomal loci. To better understand the impact of the Y chromosome on...  相似文献   
8.
Interaction of polynucleotides with natural and model membranes.   总被引:2,自引:0,他引:2       下载免费PDF全文
Polynucleotides adsorb on natural and model phospholipid membranes in the presence of Mg2+-cations. Adsorption of nucleic acids on membranes results in a considerable change of their secondary structure. The presence of model phosphatidylcholine membranes greatly stimulates the rate of the synthesis of RNA by E. coli RNA-polymerase on DNA template.  相似文献   
9.
The work was aimed at studying the transformation of 2,4-diamino-6-nitrotoluene (2,4-DA), an intermediate product in 2,4,6-trinitrotoluene catabolism by microorganisms. The results allow one to propose the following scheme for the terminal steps of TNT preparatory metabolism: 2,4-DA----[phloroglucinol carboxylic acid]----phloroglucinol----pyrogallol----ring cleavage.  相似文献   
10.
To study the evolution of the polymeric β-fructosidase (invertase) genes (SUC) of yeasts Saccharomyces, new SUC gene of S. cariocanus was cloned and sequenced and the nucleotide and amino acid sequences were compared for all known β-fructosidases of Saccharomyces species. The proteins showed 90–97% homology. The most divergent was S. bayanus β-fructosidase. The results testified again to high conservation of yeast β-fructosidases. Transitions C-T prevail in the total spectrum of nucleotide substitutions observed in the coding regions of the SUC genes; most of these transitions are in the third codon position and cause no changes in the amino acid sequences of the encoded proteins. The six Saccharomyces species each carry one (probably, non-telomeric) β-fructosidase gene. SUC is on chromosome IX in S. cerevisiae, S. bayanus, S. kudriavzevii, S. mikatae, and S. paradoxus and in a translocation region on chromosome XV in S. cariocanus.__________Translated from Molekulyarnaya Biologiya, Vol. 39, No. 3, 2005, pp. 413–419.Original Russian Text Copyright © 2005 by Korshunova, Naumova, Naumov.  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