全文获取类型
收费全文 | 593篇 |
免费 | 51篇 |
专业分类
644篇 |
出版年
2023年 | 4篇 |
2021年 | 13篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 9篇 |
2017年 | 9篇 |
2016年 | 12篇 |
2015年 | 26篇 |
2014年 | 28篇 |
2013年 | 42篇 |
2012年 | 34篇 |
2011年 | 26篇 |
2010年 | 30篇 |
2009年 | 26篇 |
2008年 | 27篇 |
2007年 | 26篇 |
2006年 | 17篇 |
2005年 | 23篇 |
2004年 | 33篇 |
2003年 | 16篇 |
2002年 | 16篇 |
2001年 | 9篇 |
2000年 | 12篇 |
1999年 | 12篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1994年 | 9篇 |
1992年 | 14篇 |
1991年 | 7篇 |
1990年 | 17篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1979年 | 9篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1973年 | 3篇 |
1971年 | 3篇 |
1970年 | 8篇 |
1966年 | 3篇 |
1965年 | 3篇 |
排序方式: 共有644条查询结果,搜索用时 0 毫秒
641.
642.
Hexyl-alpha-chymotrypsin, a hydrophobic derivative of the enzyme, is explored for the proteinase-catalyzed ester synthesis reaction with N-acetyl-L-tyrosine and ethanol. To guarantee the preservation of the enzyme activity and to allow for the extraction of the product in the organic phase, a biphasic system was used. The Vm increased for the modified enzyme. This phenomenon was linked to the modification of the protein as demonstrated by its chemical denaturation with sodium dodecyl sulfate. 相似文献
643.
644.
L Remy J P Gorvel M F Jacquier A Rigal J Davoust 《Biology of the cell / under the auspices of the European Cell Biology Organization》1990,69(3):129-138
Adenocarcinoma cells often form intracellular lumens and intercellular cysts. In order to study the structural relationships between these lumens and the apical domain of normal enterocytes, we have applied electron microscopy and confocal microscopy to a cloned cell line derived from the human colon adenocarcinoma cell line LoVo which express a high number of intracellular lumens and intercellular cysts. Microvilli reminiscent of those detected in the brush border of small intestinal cells are formed in the two types of compartments. By immunofluorescence, we found that a 135 kDa membrane glycoprotein characterized by a monoclonal Ab and normally associated with the brush-border of enterocytes is expressed at the surface of the intracellular lumens and intercellular cysts present in the adenocarcinoma cells. Comparison of fluorescence and reflection contrast micrographs obtained by confocal microscopy demonstrate the presence of spherical intracellular lumens in the juxtanuclear region of single cells, and of more complex shaped intercellular cysts located within clusters of cells. The later cells form junctional complexes limiting an apical plasma membrane domain in contact with the intercellular cyst. It is suggested that the intracellular lumens may represent the abortive form of an apical plasma membrane due to the lack of components required to establish epithelial cell contacts. As opposed to conventional fluorescence microscopy, confocal microscopy allows rapid inspection of the tridimensional organization of intracellular lumens and intercellular cysts even when they are located in cell multilayers. 相似文献