全文获取类型
收费全文 | 539篇 |
免费 | 8篇 |
国内免费 | 4篇 |
专业分类
551篇 |
出版年
2022年 | 9篇 |
2021年 | 7篇 |
2020年 | 4篇 |
2018年 | 9篇 |
2017年 | 10篇 |
2016年 | 15篇 |
2015年 | 13篇 |
2014年 | 18篇 |
2013年 | 9篇 |
2012年 | 26篇 |
2011年 | 21篇 |
2010年 | 17篇 |
2009年 | 19篇 |
2008年 | 16篇 |
2007年 | 9篇 |
2006年 | 19篇 |
2005年 | 30篇 |
2004年 | 19篇 |
2003年 | 26篇 |
2002年 | 18篇 |
2001年 | 18篇 |
2000年 | 19篇 |
1999年 | 7篇 |
1998年 | 7篇 |
1992年 | 3篇 |
1991年 | 18篇 |
1990年 | 12篇 |
1989年 | 6篇 |
1988年 | 12篇 |
1987年 | 12篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 9篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 3篇 |
1976年 | 6篇 |
1975年 | 11篇 |
1974年 | 8篇 |
1973年 | 9篇 |
1972年 | 6篇 |
1971年 | 4篇 |
1970年 | 8篇 |
1969年 | 5篇 |
1968年 | 4篇 |
1967年 | 4篇 |
1966年 | 4篇 |
1965年 | 3篇 |
排序方式: 共有551条查询结果,搜索用时 15 毫秒
541.
542.
Olga V. Egorova Vera M. Nikolayeva Galina V. Sukhodolskaya Marina V. Donova 《Journal of Molecular Catalysis .B, Enzymatic》2009,57(1-4):198-203
Redox conversions of exogenic C19-steroids (androstenedione (AD), androstadienedione (ADD), testosterone and 1(2)-dehydrotestosterone) were studied using a mutant strain of Mycobacterium sp. Et1 with high level of 17β-hydroxysteroid dehydrogenase (17-HSD) activity. Factors affecting target 17β-reduction and side reactions by resting and growing cells were estimated. The effects of glucose supplementation, pH, mode of substrate addition were identified. The results confirmed that double reduction of androstadienedione, both of 17-keto group and 1(2)-double bond, is more effective for testosterone formation than a single reduction of 17-keto group of AD. These findings argued for the application of the strain capable of sterol side chain degradation and expressed 17-HSD, 3-ketosteroid-1(2)-dehydrogenase and 1-ene-reductase activities, for testosterone obtaining from sitosterol. Under optimal conditions, the conversion of sitosterol (5 g/l) by Mycobacterium sp. VKM Ac-1816D in laboratory fermenter resulted in 50–55% molar yield of testosterone. 相似文献
543.
544.
545.
546.
547.
N N Brustovetsky M V Egorova E I Mayevsky 《Comparative biochemistry and physiology. B, Comparative biochemistry》1992,102(3):635-638
1. In the present work the initially lowered oxidase activity of liver mitochondria of hibernating gophers is shown to increase upon Ca(2+)-loading, after freezing-thawing repeated three times and after swelling in a medium containing potassium acetate as well as in a hypotonic sucrose medium. 2. In all cases the inhibition of phospholipase A2 hindered the increase of the oxidase activity of mitochondria. 3. Mitochondria of hibernating gophers have a lowered delta psi in comparison with active animals, which is restored in the hypotonic medium. 相似文献
548.
N N Brustovetsky M V Egorova E V Grishina E I Mayevsky 《Comparative biochemistry and physiology. B, Comparative biochemistry》1992,103(3):755-758
1. The causes of the suppression of oxidative phosphorylation and energy-dependent cationic transport into liver mitochondria of hibernating gophers have been analysed. 2. The decrease of the ATP synthesis rate and suppression of the energy-dependent K(+)- and Ca(2+)-transport into mitochondria during hibernation has been found to be mainly related to a delta psi decrease in mitochondria of hibernating gophers. 3. The increase delta psi upon incubation of the mitochondria of hibernating animals in a hypotonic medium results in an essential acceleration of ATP synthesis and energy-dependent cationic transport. 相似文献
549.
550.
V I Levenson Z P Belkin T P Egorova 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1991,(8):5-9
The isolation and properties of endotoxin protein, or lipid A-associated protein (LAP), from Shigella sonnei were described earlier (Zh. mikrobiol. epidemiol. immunobiol., 1991, No. 4, pp. 11-17, and No. 7). In this report the data on its protective activity are presented. In experiments on mice one nanogram of LAP injected i. v. protected 50% of the animals against i. p. challenge with 40 LD50 of virulent S. sonnei. Guinea pigs injected s. c. with 10 micrograms of LAP were protected against local (keratoconjunctival) challenge with S. sonnei, the efficiency of immunization being 58%. LAP preparations containing no detectable amounts of O-antigen (less than 0.003%) were found to have a protective effect. Hyperimmune anti-LAP rabbit serum prevented local infection when incubated with S. sonnei challenge inoculum before injection into guinea pigs. Both active and passive protection induced by LAP was specific since no effect was observed in animals challenged with Shigella flexneri. In the homologous system the protective effect of anti-LAP serum was abolished by the addition of protein-free LPS. These results are compatible with the hypothesis that the protective activity of LAP depends on the presence of minute amounts of O-antigen whose immunogenic effect is greatly amplified by the protein component of the natural endotoxin complex. 相似文献