全文获取类型
收费全文 | 8772篇 |
免费 | 542篇 |
出版年
2023年 | 62篇 |
2022年 | 50篇 |
2021年 | 206篇 |
2020年 | 150篇 |
2019年 | 163篇 |
2018年 | 221篇 |
2017年 | 177篇 |
2016年 | 300篇 |
2015年 | 460篇 |
2014年 | 455篇 |
2013年 | 661篇 |
2012年 | 707篇 |
2011年 | 692篇 |
2010年 | 448篇 |
2009年 | 411篇 |
2008年 | 497篇 |
2007年 | 492篇 |
2006年 | 470篇 |
2005年 | 451篇 |
2004年 | 410篇 |
2003年 | 360篇 |
2002年 | 366篇 |
2001年 | 68篇 |
2000年 | 45篇 |
1999年 | 69篇 |
1998年 | 75篇 |
1997年 | 83篇 |
1996年 | 52篇 |
1995年 | 63篇 |
1994年 | 54篇 |
1993年 | 47篇 |
1992年 | 32篇 |
1991年 | 41篇 |
1990年 | 29篇 |
1989年 | 18篇 |
1988年 | 28篇 |
1987年 | 23篇 |
1985年 | 18篇 |
1984年 | 34篇 |
1983年 | 26篇 |
1982年 | 28篇 |
1981年 | 35篇 |
1980年 | 28篇 |
1979年 | 17篇 |
1978年 | 28篇 |
1977年 | 17篇 |
1976年 | 17篇 |
1975年 | 10篇 |
1974年 | 12篇 |
1965年 | 10篇 |
排序方式: 共有9314条查询结果,搜索用时 203 毫秒
61.
Ana Rosa Santa Cruza Luis A. Quesada Allue Alberto Baldi 《Molecular and cellular biochemistry》1983,56(1):55-66
Microsomal preparations from malignant human breast tumors catalyzed the transfer of mannose and glucose from GDP-[14C]-Man and UDP-[14C]-Glc into lipid-linked sugars and glycoprotein-like substances. As judged by several criteria the obtained lipid-linked monosaccharides behaved as dolichyl phosphate mannose and dolichyl phosphate glucose whereas lipid-linked oligosaccharides behaved as polyprenyl diphosphate derivatives. The optimum conditions for mannosyl- and glucosyl-transfer reactions and the effect of dolichyl phosphate, detergent and EDTA on incubation mixture were described. 相似文献
62.
63.
64.
65.
66.
67.
68.
Reaction center-B875 pigment-protein complexes were purified from Rhodocyclus gelatinosus. The proteic components consist of 7–8 polypeptides among which some were identified by their apparent molecular weights: the light harvesting B875 polypeptides and of 8 and 6 kDa, reaction center L (23 kDa), M (28 kDa) and H (34 kDa), cytochrome c (43 kDa). Four c-type hemes were found per reaction center. Flash-induced absorbance changes showed the presence of both QA and QB in the complex. Charge recombination times were determined to be: 1.16±0.2 (n=30) for P+QAQB
- and 7–10 ms for P+QA
- in presence of herbicides. From quinone analysis on one hand and kinetics of charge recombination on the other hand, we proposed that in the reaction center of Rhodocyclus gelatinosus QA is menaquinone 8 and QB is ubiquinone 8. 相似文献
69.
70.
The Lotka-Volterra competition model was used to represent the interaction between Laurencia obtusa and Hypnea spinella. A new model that considers effects of competition on algal carrying capacity is suggested. To test the models, data from field experiments conducted in an intertidal region at Cabo Frio Island, Rio de Janeiro, Brazil, were used. Both models showed that Hypnea was a stronger competitor than Laurencia. The model of interaction through the carrying capacity showed a stable coexistence between the algal populations and better represented the experimental data. 相似文献