全文获取类型
收费全文 | 321篇 |
免费 | 26篇 |
出版年
2019年 | 2篇 |
2017年 | 7篇 |
2016年 | 8篇 |
2015年 | 12篇 |
2014年 | 11篇 |
2013年 | 9篇 |
2012年 | 12篇 |
2011年 | 10篇 |
2010年 | 14篇 |
2009年 | 12篇 |
2008年 | 12篇 |
2007年 | 11篇 |
2006年 | 8篇 |
2005年 | 15篇 |
2004年 | 14篇 |
2003年 | 15篇 |
2002年 | 11篇 |
2001年 | 20篇 |
2000年 | 12篇 |
1999年 | 11篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 8篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 9篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 8篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 2篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 6篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1969年 | 1篇 |
1965年 | 1篇 |
1934年 | 1篇 |
排序方式: 共有347条查询结果,搜索用时 15 毫秒
91.
92.
93.
Wagner Vital Gustavo Lazzaro Rezende Leonardo Abreu Jorge Moraes Francisco JA Lemos Itabajara da Silva VazJr Carlos Logullo 《BMC developmental biology》2010,10(1):25
Background
The mosquito A. aegypti is vector of dengue and other viruses. New methods of vector control are needed and can be achieved by a better understanding of the life cycle of this insect. Embryogenesis is a part of A. aegypty life cycle that is poorly understood. In insects in general and in mosquitoes in particular energetic metabolism is well studied during oogenesis, when the oocyte exhibits fast growth, accumulating carbohydrates, lipids and proteins that will meet the regulatory and metabolic needs of the developing embryo. On the other hand, events related with energetic metabolism during A. aegypti embryogenesis are unknown. 相似文献94.
95.
Well-known as an important regulator of lipid metabolism and adipocyte differentiation, the peroxisome proliferator-activated receptor gamma (PPARgamma) also has potential use as a target for antitumor therapy in certain cancers. To develop agents for radionuclide imaging PPARgamma in vivo, we synthesized fluorine, bromine, and iodine-substituted analogs (1-3) of a high-affinity benzophenone-tyrosine PPARgamma ligand; all three analogs retain very high affinity for the PPARgamma receptor. In preparation for the synthesis of these PPARgamma ligands in radiolabeled form, we have synthesized two types of precursors: (a) an aryltributylstannane (9), from which the bromine and iodine-substituted analogs (2 and 3) can readily be prepared by electrophilic destannylation, and (b) three diaryliodonium tosylate derivatives (12a-c), precursors for nucleophilic aromatic fluorination using fluoride ion. Conditions were developed whereby the thiophenyliodonium tosylate (12c) underwent nucleophilic aromatic substitution with fluoride ion, efficiently and in short reaction times, to produce the desired fluorine-substituted target compound 1. These reactions laid the groundwork for producing these three PPARgamma ligands in radiolabeled form; in addition, our use of diaryliodonium ion precursors for aromatic fluorination in this series provides an example that should encourage application of this approach for radiofluorination of more complicated radiopharmaceuticals. 相似文献
96.
A tripodal bifunctional chelator for gallium has been prepared with a chelation core consisting of three thiols and a tertiary amine. The synthesis proceeds in 13 steps with an overall yield of 22%. An aromatic amine is available for conjugation to peptides through carbodiimide coupling. Gallium(III) complexes were readily prepared from both the bifunctional chelator and a phenylalanine-conjugated system. These complexes underwent stability evaluation and were found to be stable to ligand exchange and enzymatic hydrolysis. This bifunctional chelator appears to be suitable for conjugation to peptides for the preparation of gallium radiopharmaceuticals. 相似文献
97.
98.
99.
Katzenellenbogen E Kocharova NA Zatonsky GV Bogulska M Rybka J Gamian A Shashkov AS Knirel YA 《Carbohydrate research》2003,338(13):1389-1395
The O-specific polysaccharide of the lipopolysaccharide of Citrobacter gillenii PCM 1540 (serogroup O11) consists of D-Glc, D-Man, D-GalNAc, D-GlcNAc, 2-acetamido-2,6-dideoxy-D-galactose (D-FucNAc) and O-acetyl groups in the ratios 2:1:1:1:1:1. On the basis of sugar and methylation analyses and Smith-degradation along with 1D and 2D 1H and 13C NMR spectroscopy, the following structure of the branched hexasaccharide repeating unit was established: [structure: see text]. Citrobacter werkmanii PCM 1541 belonging to the same serogroup O11 was found to have an R-form lipopolysaccharide devoid of the O-specific polysaccharide. 相似文献
100.