全文获取类型
收费全文 | 1358篇 |
免费 | 68篇 |
国内免费 | 2篇 |
出版年
2023年 | 5篇 |
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 13篇 |
2017年 | 19篇 |
2016年 | 24篇 |
2015年 | 31篇 |
2014年 | 44篇 |
2013年 | 91篇 |
2012年 | 65篇 |
2011年 | 74篇 |
2010年 | 46篇 |
2009年 | 35篇 |
2008年 | 45篇 |
2007年 | 65篇 |
2006年 | 70篇 |
2005年 | 62篇 |
2004年 | 88篇 |
2003年 | 73篇 |
2002年 | 66篇 |
2001年 | 37篇 |
2000年 | 37篇 |
1999年 | 36篇 |
1998年 | 21篇 |
1997年 | 27篇 |
1996年 | 26篇 |
1995年 | 22篇 |
1994年 | 31篇 |
1993年 | 24篇 |
1992年 | 19篇 |
1991年 | 24篇 |
1990年 | 19篇 |
1989年 | 9篇 |
1988年 | 16篇 |
1987年 | 11篇 |
1986年 | 9篇 |
1985年 | 14篇 |
1984年 | 11篇 |
1982年 | 10篇 |
1981年 | 12篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1977年 | 12篇 |
1976年 | 10篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1971年 | 4篇 |
排序方式: 共有1428条查询结果,搜索用时 277 毫秒
41.
42.
43.
Hydroperoxide decomposition by the NADP-glutathione system in rat liver mitochondria was analyzed. Mitochondria were found to contain high concentrations of the reduced form of glutathione (GSH) (4.32 +/- 0.50 nmol/mg) and NADPH (4.74 +/- 0.64 nmol/mg), and high activities of glutathione peroxidase and reductase. In the initial phase of the reaction, the rate of hydroperoxide decomposition was proportional to both the GSH level and the activity of GSH peroxidase. However, in the later steady state, the step of NADP reduction was rate-limiting, and the overall reaction rate was independent of the initial concentration of GSH, and activities of glutathione peroxidase and reductase. Some GSH was released from mitochondria during incubation, but the rate of the decomposition could be simply expressed as kappa [GSH]/2, where kappa is the first-order rate constant of the peroxidase and [GSH] is the intramitochondrial level of GSH in the steady state. The rate of the reaction in the steady state was also dependent on the NADPH level, its reciprocal being linearly correlated with [NADPH]-1. The rate of decomposition of hydroperoxide was influenced by the respiratory state. During state 3 respiration, the rate was greatly depressed, but was still considered to exceed by far the rate of physiological generation of hydroperoxide. 相似文献
44.
Transport of glutathione across the mitochondrial membranes 总被引:4,自引:0,他引:4
K Kurosawa N Hayashi N Sato T Kamada K Tagawa 《Biochemical and biophysical research communications》1990,167(1):367-372
Transport of glutathione (GSH) into mitochondria was observed when mitochondria in state 4 respiration were incubated with high concentrations of GSH. This transport was suppressed by antimycin A or dicyclohexyl-carbodiimide, or in state 3 respiration. Upon dissipation of the proton gradient by a proton ionophore, mitochondrial GSH was released into the medium. GSH moved freely across the proton-permeated mitochondrial membrane, its movement depending only on the GSH gradient across the inner membrane. These results indicate that there is a transport system for GSH in the mitochondrial membrane, and that a proton gradient is necessary to maintain GSH in the matrix, and to transport GSH into mitochondria. 相似文献
45.
46.
The constituents of Virola carinata were established as dehydrodieugenol, its monomethyl ether and sitosterol. 相似文献
47.
Masatoshi Takeichi Tadao Atsumi Chikako Yoshida Kazuko Uno T.S. Okada 《Developmental biology》1981,87(2):340-350
The specificity of adhesion between embryonal carcinoma cells and fibroblastic cells of various origins was studied. Embryonal carcinoma cells have intercellular adhesion sites requiring Ca2+ (CDS). These sites were found to be sensitive to proteases but resistant to them in the presence of Ca2+. CDS with a similar protease sensitivity is present in fibroblastic cells. When embryonal carcinoma cells of different lines were mixed, they adhered to each other nonselectively by CDS. Nonselective adhesion by CDS occurred also between fibroblastic cells of various lines. When embryonal carcinoma and fibroblastic cells were mixed, they preferentially adhered to homotypic cells. Fab fragments of antibodies raised against F9 cells (a nullipotent line of embryonal carcinoma) inhibited the adhesion between embryonal carcinoma cells but not between fibroblastic cells. This inhibitory activity of Fab was absorbed with embryonal carcinoma cells with CDS, but not with fibroblastic cells with CDS or embryonal carcinoma cells from which CDS was experimentally removed. SDS-polyacrylamide gel electrophoresis of radioiodinated cell surface proteins showed that the presence of a 140K-dalton component correlated with the presence of CDS in embryonal carcinoma cells, while the presence of a 150K-dalton component correlated with the presence of CDS in fibroblastic cells. These results suggest that CDS in embryonal carcinoma and fibroblastic cells comprise distinct molecules. 相似文献
48.
Three new alkaloids isolated from Banisteriopsis caapi, were identified as harmic amide (1-carbamoyl-7-methoxy β-carboline), acetyl norharmine (1-acetyl-7-methoxy β-carboline) and ketotetrahydronorharmine (7-methoxy-1,2,3,4-tetrahydro-1-oxo-β-carboline) 相似文献
49.
Hiroo Horinishi Shuichi Hashizume Masaharu Seguchi Kazuko Takahashi 《Biochemical and biophysical research communications》1975,67(3):1136-1143
A soluble fraction from Escherichia coli B was found to incorporate methionine into 95°C CCl3COOH-insoluble fraction. The incorporation required methionyl-tRNA synthetase, methionine tRNA, ATP, Mg2+ and bovine milk casein. The casein could be replaced by arginylated bovine serum albumin and arginylated bovine α-lactalbumin. A mixture of 19 amino acids other than methionine and GTP had no effect on the incorporation. KCl was rather inhibitory. Puromycin, RNase A and trypsin inhibited the incorporation, while DNase I did not. The soluble fraction also incorporated the methionyl moiety of methionyl-tRNA. This incorporation was not affected by the addition of free methionine. 相似文献
50.
Three new bases were isolated from Banisteriopsis caapi; they are harmine N-oxide, harmic acid methyl ester (methyl 7-methoxy-β-carboline 1-carboxylate) and harmalinic acid (7-methoxy-3,4-dihydro-β-carboline 1-carboxylic acid). 相似文献