全文获取类型
收费全文 | 445篇 |
免费 | 7篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 36篇 |
金属工艺 | 14篇 |
机械仪表 | 2篇 |
建筑科学 | 12篇 |
矿业工程 | 2篇 |
能源动力 | 8篇 |
轻工业 | 49篇 |
水利工程 | 4篇 |
石油天然气 | 5篇 |
无线电 | 33篇 |
一般工业技术 | 44篇 |
冶金工业 | 208篇 |
原子能技术 | 1篇 |
自动化技术 | 30篇 |
出版年
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 18篇 |
2012年 | 5篇 |
2011年 | 12篇 |
2010年 | 14篇 |
2009年 | 8篇 |
2008年 | 8篇 |
2007年 | 8篇 |
2006年 | 8篇 |
2005年 | 11篇 |
2004年 | 10篇 |
2003年 | 8篇 |
2002年 | 10篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 20篇 |
1998年 | 50篇 |
1997年 | 29篇 |
1996年 | 22篇 |
1995年 | 6篇 |
1994年 | 11篇 |
1993年 | 16篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 11篇 |
1989年 | 7篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 9篇 |
1978年 | 3篇 |
1977年 | 7篇 |
1976年 | 14篇 |
1975年 | 5篇 |
1973年 | 6篇 |
1971年 | 2篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有452条查询结果,搜索用时 0 毫秒
451.
A Comoglio AH Gibbs IN White T Gant EA Martin LL Smith SR Gamalero F DeMatteis 《Canadian Metallurgical Quarterly》1996,17(8):1687-1693
Tamoxifen induces hepatocellular carcinomas in rats and is converted by rat hepatic cytochrome P450 enzymes into reactive metabolites capable of forming adducts with nucleic acids, proteins and chromosomal aberrations. In rats tamoxifen has also been shown to induce liver cytochrome P450 enzymes, to stimulate its own metabolism leading to greater covalent binding and to induce a higher degree of unscheduled DNA synthesis. This suggests that, at least in the rat, a sensitive species, tamoxifen may contribute significantly to its genotoxic and carcinogenic potential, by assisting its own metabolic activation. We have now investigated the effect of feeding tamoxifen to male and female Rhesus monkeys. A marked induction of the hepatic cytochrome(s) P450 is found in the monkey but, in spite of this, the in vitro metabolism of 7-ethoxyresorufin by microsomes from treated animals is markedly inhibited and so is the dealkylation of two other 7-alkoxyresorufin substrates. Evidence is presented for the accumulation in the liver of monkeys treated with tamoxifen of a powerful inhibitor of drug metabolism, and the inhibitor is identified as a metabolite of tamoxifen, its N,N-didesmethyl derivative. The level of 32P-postlabelled DNA adducts was considerably higher in rats given tamoxifen than in similarly treated monkeys. Also, whereas rats responded to tamoxifen treatment with a marked increase in covalent binding to microsomal protein, in the monkeys, where accumulation of the inhibitory metabolite in the microsomal fraction was also seen, covalent binding was not greater with microsomes from treated animals than in the corresponding controls. N,N-Didesmethyl-tamoxifen, added in vitro to human and rat microsomes, reduced significantly the extent of covalent binding, suggesting that the accumulation of the metabolite observed in the liver of primates may discourage the cytochrome P450-dependent conversion of tamoxifen into reactive derivatives and in this way protect against the formation of adducts. This mechanism may also contribute to protecting the primate against tamoxifen- induced liver cancer. 相似文献
452.