全文获取类型
收费全文 | 1343篇 |
免费 | 74篇 |
国内免费 | 1篇 |
出版年
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 8篇 |
2018年 | 17篇 |
2017年 | 17篇 |
2016年 | 20篇 |
2015年 | 19篇 |
2014年 | 42篇 |
2013年 | 46篇 |
2012年 | 79篇 |
2011年 | 63篇 |
2010年 | 35篇 |
2009年 | 52篇 |
2008年 | 66篇 |
2007年 | 61篇 |
2006年 | 60篇 |
2005年 | 66篇 |
2004年 | 75篇 |
2003年 | 56篇 |
2002年 | 64篇 |
2001年 | 37篇 |
2000年 | 38篇 |
1999年 | 35篇 |
1998年 | 13篇 |
1997年 | 15篇 |
1996年 | 9篇 |
1995年 | 14篇 |
1994年 | 12篇 |
1993年 | 12篇 |
1992年 | 28篇 |
1991年 | 30篇 |
1990年 | 30篇 |
1989年 | 27篇 |
1988年 | 22篇 |
1987年 | 20篇 |
1986年 | 22篇 |
1985年 | 17篇 |
1984年 | 16篇 |
1983年 | 11篇 |
1982年 | 10篇 |
1980年 | 7篇 |
1979年 | 14篇 |
1978年 | 16篇 |
1977年 | 8篇 |
1976年 | 8篇 |
1974年 | 8篇 |
1972年 | 11篇 |
1971年 | 14篇 |
1970年 | 8篇 |
1969年 | 9篇 |
排序方式: 共有1418条查询结果,搜索用时 14 毫秒
1.
2.
3.
Genes for the biosynthesis of spinosyns: applications for yield improvement in Saccharopolyspora spinosa 总被引:2,自引:0,他引:2
K Madduri C Waldron P Matsushima M C Broughton K Crawford D J Merlo R H Baltz 《Journal of industrial microbiology & biotechnology》2001,27(6):399-402
Spinosyns A and D are the active ingredients in an insect control agent produced by fermentation of Saccharopolyspora spinosa. Spinosyns are macrolides with a 21-carbon, tetracyclic lactone backbone to which the deoxysugars forosamine and tri-O-methylrhamnose are attached. The spinosyn biosynthesis genes, except for the rhamnose genes, are located in a cluster that
spans 74 kb of the S. spinosa genome. DNA sequence analysis, targeted gene disruptions and bioconversion studies identified five large genes encoding type
I polyketide synthase subunits, and 14 genes involved in sugar biosynthesis, sugar attachment to the polyketide or cross-bridging
of the polyketide. Four rhamnose biosynthetic genes, two of which are also necessary for forosamine biosynthesis, are located
outside the spinosyn gene cluster. Duplication of the spinosyn genes linked to the polyketide synthase genes stimulated the
final step in the biosynthesis — the conversion of the forosamine-less pseudoaglycones to endproducts. Duplication of genes
involved in the early steps of deoxysugar biosynthesis increased spinosyn yield significantly. Journal of Industrial Microbiology & Biotechnology (2001) 27, 399–402.
Received 31 May 2001/ Accepted in revised form 09 July 2001 相似文献
4.
Molecular cloning and DNA sequence analysis of the human guanine nucleotide-binding protein Go alpha 总被引:4,自引:0,他引:4
S Lavu J Clark R Swarup K Matsushima K Paturu J Moss H F Kung 《Biochemical and biophysical research communications》1988,150(2):811-815
The nucleotide sequence of human Go alpha was determined from a partial human brain cDNA clone and the sequence of the first two 5' coding exons of a human genomic Go alpha clone. Comparison of this sequence with bovine and rat Go alpha shows greater than 90% homology at the nucleotide and deduced amino acid level. There is 100% identity at the amino acid level for the cholera and pertussis toxin-catalyzed ADP ribosylation sites, the putative guanine nucleotide binding, and the GTP hydrolysis sites. 相似文献
5.
6.
This paper comments on the evaluation of Erin and co-workers (Biochim. Biophys. Acta 774 (1984) 96-102) of equilibrium constants for alpha-tocopherol interactions with fatty acids on the basis of the changes of absorbance in a 200 nm ultraviolet region. It is concluded that the ultraviolet method is inadequate because it is affected by absorption in that region of the solvent, ethanol and fatty acids which they used. 相似文献
7.
8.
9.
Summary A newly isolated bacterium, strain TB-135, produces solely D-lactic acid from 1,2-propanediol (1,2-PD). From taxonomical studies, the strain was concluded to belong to the genusPseudomonas. The optimal conditions for the acid production were found to be at 4% 1,2-PD and 0.2% yeast extract, when the strain produced 21mg/ml of the acid of a high optical purity (over 99% e.e.) after 4days of cultivation. Since it was considered that the acid was produced from (R)-(–)-1,2-PD, the molar yield was estimated to be 86%. 相似文献
10.
A Ajima S G Cao K Takahashi A Matsushima Y Saito Y Inada 《Biotechnology and applied biochemistry》1987,9(1):53-57
Hemin, having two carboxyl groups, was coupled with alpha-(3-aminopropyl)-omega-methoxypoly(oxyethylene) through the acid-amide bond formed with carbodiimide. The modified hemin catalyzed the peroxidase reaction in 1,1,1-trichloroethane using benzoyl peroxide or peroxides in unsaturated fatty acids as the hydrogen acceptor and leuco crystal violet as the hydrogen donor. A basic study on quantitative microanalysis of the lipid peroxides was attempted. 相似文献