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   527篇
  免费   28篇
  555篇
  2023年   3篇
  2022年   6篇
  2021年   13篇
  2020年   5篇
  2019年   9篇
  2018年   19篇
  2017年   10篇
  2016年   17篇
  2015年   21篇
  2014年   25篇
  2013年   43篇
  2012年   34篇
  2011年   41篇
  2010年   25篇
  2009年   27篇
  2008年   27篇
  2007年   34篇
  2006年   27篇
  2005年   23篇
  2004年   25篇
  2003年   21篇
  2002年   16篇
  2001年   6篇
  2000年   3篇
  1999年   7篇
  1998年   4篇
  1997年   2篇
  1996年   2篇
  1994年   2篇
  1993年   3篇
  1992年   3篇
  1991年   2篇
  1990年   4篇
  1989年   4篇
  1988年   6篇
  1987年   5篇
  1985年   3篇
  1984年   4篇
  1983年   3篇
  1981年   1篇
  1980年   2篇
  1977年   3篇
  1976年   2篇
  1975年   2篇
  1973年   2篇
  1972年   1篇
  1971年   1篇
  1969年   1篇
  1968年   1篇
  1966年   1篇
排序方式: 共有555条查询结果,搜索用时 0 毫秒
551.
552.
We report the amino acid sequence of a basic protein isolated from the snake venom of Naja naja atra. An automated Edman sequencer was used to determine the 65-residue sequence, aided by electrospray ionization/mass spectrometry. Online reduction and pyridylethylation of the peptide was performed to identify the cysteine residues. Trypsin, chymotrypsin and aspartic digestions were carried out to derive peptide fragments for further sequencing. Fragmented peptides were overlapped to obtain the complete sequence. Molecular mass measurements of the whole protein and its fragments were used as a countercheck for sequence assignment. Further confirmation of the sequence was indicated by sequence homology to other snake venom neurotoxins. A molecular model of the tertiary structure was constructed based on sequence homology, and was refined by global minimization and extensive quality control algorithms. Electrostatic and hydrophobic surface calculations and molecular dynamics simulations were carried out to determine the functional properties of the molecule.  相似文献   
553.
Leptospirosis is recognized as the most widespread zoonosis with a global distribution. In this study, the antigenic variation in Leptospira interrogans and Leptospira borgpetersenii isolated from human urine and field rat kidney was preliminarily confirmed by microscopic agglutination test using monoclonal antibodies, and was further subjected to amplification and identification of outer membrane lipoproteins with structural gene variation. Sequence similarity analysis revealed that these protein sequences...  相似文献   
554.
The derivation of the restricted intra-sire regression heritability estimator is provided. Procedures for obtaining a stable estimate of residual error variance σ2 are outlined. A small illustration based on live data is given.  相似文献   
555.
Water and soil samples were collected from natural habitats of the nine-banded armadillo and tested for the presence of acid-fast organisms by injection into the foot pads of experimental mice. Sixteen months post inoculation an acid-fast organism was isolated from the foot pad and spleen of one of the mice. The isolate exhibited diphenoloxidase activity as determined by its ability to convert D-3,4-dihydroxyphenylalanine to the corresponding quinone. The same organisms grown in vitro lacked detectable diphenoloxidase activity. However, diphenoloxidase activity was observed in acid-fast organisms harvested from spleen tissue of mice experimentally inoculated with a pure culture of the isolate. The environmental isolate was tentatively classed with the Mycobacterium avium-intracellulare complex.  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