全文获取类型
收费全文 | 2267篇 |
免费 | 192篇 |
国内免费 | 1篇 |
出版年
2021年 | 10篇 |
2020年 | 10篇 |
2018年 | 16篇 |
2017年 | 14篇 |
2016年 | 36篇 |
2015年 | 40篇 |
2014年 | 54篇 |
2013年 | 185篇 |
2012年 | 102篇 |
2011年 | 133篇 |
2010年 | 62篇 |
2009年 | 57篇 |
2008年 | 120篇 |
2007年 | 102篇 |
2006年 | 102篇 |
2005年 | 111篇 |
2004年 | 125篇 |
2003年 | 130篇 |
2002年 | 134篇 |
2001年 | 47篇 |
2000年 | 53篇 |
1999年 | 49篇 |
1998年 | 38篇 |
1997年 | 37篇 |
1996年 | 29篇 |
1995年 | 22篇 |
1994年 | 32篇 |
1993年 | 27篇 |
1992年 | 48篇 |
1991年 | 30篇 |
1990年 | 42篇 |
1989年 | 38篇 |
1988年 | 45篇 |
1987年 | 35篇 |
1986年 | 28篇 |
1985年 | 27篇 |
1984年 | 19篇 |
1983年 | 14篇 |
1982年 | 22篇 |
1981年 | 10篇 |
1980年 | 17篇 |
1979年 | 25篇 |
1978年 | 26篇 |
1977年 | 18篇 |
1975年 | 16篇 |
1974年 | 16篇 |
1973年 | 15篇 |
1971年 | 10篇 |
1970年 | 15篇 |
1968年 | 13篇 |
排序方式: 共有2460条查询结果,搜索用时 15 毫秒
31.
32.
Hideya Hayashi Seiji Ito Teruo Tanaka Manabu Negishi Hideo Kawabe Yokohama Hiromitsu Kikuko Watanabe Osamu Hayaishi 《Prostaglandins & other lipid mediators》1987,33(4)
In view of the recent finding that prostaglandin D2 is stereospecifically converted to 9α,11β-prostaglandin F2, an isomer of prostaglandin F2α, a highly specific and sensitive radioimmunoassay for 9α,11β-prostaglandin F2 was developed and applied to determine the content of this prostaglandin in various rat tissues. Antisera against 9α-11β-prostaglandin F2 were raised in rabbits immunized with the bovine serum albumin conjugate, and [3H]9α,11β-prostaglandin F2 was enzymatically prepared from [3H]prostaglandin D2. The assay detected 9α,11β-prostaglandin F2 over the range of 20 pg to 1 ng, and the antiserum showed less than 0.04% cross-section with prostaglandin F2α, prostaglandin F2β and 9β,11β-prostaglandin F2. To avoid postmortem changes, tissues were frozen in liquid nitrogen immediately after removal. The basal level of 9α,11β-prostaglandin F2 was hardly detectable in various tissues of the rat examined, including spleen, lung, liver and brain; although it was found to be 0.31 ± 0.06 ng/g wet weight in the small intestine. During convulsion induced by pentylenetetrazole, enormous amounts of prostaglandin D2 (ca. 180 ng/g wet weight) and prostaglandin F2α (ca. 70 ng/g) were produced in the brain; however, 9α,11β-prostaglandin F2 was detected neither there nor in the blood. This result demonstrates that the conversion to 9α,11β-prostaglandin F2 is a minor pathway, if one at all, of prostaglandin D2 metabolism in the rat brain. 相似文献
33.
Isopropylidenation of lactose with 2,2-dimethoxypropane in the presence ofp-toluenesulfonic acid gave two products, which were identified by1H- and13C-NMR as 2,35,63,4-tri-O-isopropylidenelactose dimethyl acetal (1) and its 6-O-(2-methoxy)-isopropyl derivative (2). These products were used for the synthesis of 2-O-methyllactose (7), 2,6-di-O-methyllactose (9) and 2-O-benzyllactose (13). 相似文献
34.
35.
36.
37.
Inactivation of kanamycin, neomycin, and streptomycin by enzymes obtained in cells of Pseudomonas aeruginoa 总被引:8,自引:0,他引:8
下载免费PDF全文
![点击此处可从《Applied microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ten strains of Pseudomonas aeruginosa were disrupted and centrifuged. The supernatant fluids from centrifugation at 105,000 x g contained enzymes inactivating kanamycin, neomycin, and streptomycin in the presence of adenosine triphosphate. Kanamycin-inactivating enzyme was precipitated with ammonium sulfate at 66% of saturated concentration, and the inactivated kanamycin was shown to be kanamycin-3'-phosphate in which the C-3 hydroxyl group of 6-amino-6-deoxy-d-glucose moiety was phosphorylated. This is identical with kanamycin inactivated by Escherichia coli carrying R factor. Streptomycin-inactivating enzyme was precipitated with ammonium sulfate at 33% of saturated concentration. 相似文献
38.
The NH2-terminal residues of Bacillus subtilis proteins 总被引:4,自引:0,他引:4
39.
40.