全文获取类型
收费全文 | 468篇 |
免费 | 93篇 |
出版年
2021年 | 8篇 |
2020年 | 5篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2015年 | 14篇 |
2014年 | 15篇 |
2013年 | 18篇 |
2012年 | 21篇 |
2011年 | 16篇 |
2010年 | 17篇 |
2009年 | 8篇 |
2008年 | 17篇 |
2007年 | 17篇 |
2006年 | 14篇 |
2005年 | 20篇 |
2004年 | 26篇 |
2003年 | 13篇 |
2002年 | 19篇 |
2001年 | 7篇 |
2000年 | 15篇 |
1999年 | 18篇 |
1998年 | 14篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 11篇 |
1992年 | 11篇 |
1991年 | 11篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 10篇 |
1987年 | 14篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1982年 | 5篇 |
1979年 | 5篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1974年 | 11篇 |
1973年 | 8篇 |
1972年 | 5篇 |
1971年 | 7篇 |
1969年 | 5篇 |
1968年 | 7篇 |
1962年 | 6篇 |
1946年 | 5篇 |
1926年 | 4篇 |
1925年 | 3篇 |
排序方式: 共有561条查询结果,搜索用时 15 毫秒
81.
82.
83.
A Yasui A J Douglas B Walker D F Magee R F Murphy 《International journal of peptide and protein research》1990,35(4):301-305
The C-terminal tetrapeptide, Trp-Met-Asp-Phe-NH2, is a full agonist of gastrin, but des-Phe analogues, including Boc-Trp-Met-Asp-NH2, are antagonists. To ascertain the minimum structural requirement for an antagonist, we used conventional solution phase methodology to synthesize analogues with further modifications including removal of the alpha-amino group of Trp, conversion of the indole to a phenyl ring, and methylation of amide bonds. These analogues were tested for their effect on pentagastrin-stimulated acid release in dogs surgically prepared with a gastric fistula. When infused intravenously at a dose of 20 pmol kg-1 h-1, the peptides significantly inhibited acid secretion. The extent of inhibition ranged from 12% to 60%. Thus, tripeptide analogues based on the C-terminal sequence of gastrin act as potent and specific antagonists of gastrin-stimulated acid secretion. 相似文献
84.
The dog is the main reservoir of Leishmania infantum, the causative agent of visceral leishmaniasis (VL) in humans in Southern Europe. In order to identify the risk of dogs from
a Leishmania non-endemic area traveling to a Leishmania -endemic area becoming infected and the risk of transmitting infection to humans in non-endemic areas an investigation was
performed, in which the results of a questionnaire were combined with the results of a serologic survey. 相似文献
85.
86.
87.
THE INTERACTION OF CATIONIC LIPOSOMES CONTAINING ENTRAPPED HORSERADISH PEROXIDASE WITH CELLS IN CULTURE 总被引:8,自引:6,他引:2 下载免费PDF全文
Wayne E. Magee Charles W. Goff Jean Schoknecht M. Diane Smith K. Cherian 《The Journal of cell biology》1974,63(2):492-504
Cationic liposomes composed of sphingomyelin, cholesterol, and stearylamine were prepared with horseradish peroxidase trapped inside. Stable particles were formed in which 10–12% of the enzymic activity appeared to be located at, or near, the outer surface of the liposome. Adsorption and uptake of liposomes by HeLa cells were followed cytochemically by electron microscopy and quantitated by enzyme assay and by the distribution and fate of particles labeled with [14C]cholesterol and [125I]horseradish peroxidase. The particles were adsorbed by HeLa cells at least 300 times as efficiently as was free horseradish peroxidase. Many of the particles remained at the cell surface, but numerous membrane-bound cytoplasmic inclusions were observed to contain peroxidase-staining material. In addition, many areas of the cell membrane gave a positive staining reaction. It was concluded that many particles (presumably the larger ones) did not gain access to the interior of the cells, many were phagocytized, and some enzyme was transferred to the cell membrane, perhaps as a result of fusion of the liposomal membrane with the cell membrane. 相似文献
88.
89.
90.