全文获取类型
收费全文 | 94534篇 |
免费 | 461篇 |
国内免费 | 884篇 |
专业分类
95879篇 |
出版年
2022年 | 18篇 |
2021年 | 36篇 |
2020年 | 21篇 |
2018年 | 11857篇 |
2017年 | 10692篇 |
2016年 | 7479篇 |
2015年 | 631篇 |
2014年 | 325篇 |
2013年 | 356篇 |
2012年 | 4263篇 |
2011年 | 12867篇 |
2010年 | 12038篇 |
2009年 | 8256篇 |
2008年 | 9834篇 |
2007年 | 11413篇 |
2006年 | 316篇 |
2005年 | 549篇 |
2004年 | 1003篇 |
2003年 | 1078篇 |
2002年 | 814篇 |
2001年 | 297篇 |
2000年 | 206篇 |
1999年 | 61篇 |
1998年 | 26篇 |
1997年 | 34篇 |
1996年 | 24篇 |
1993年 | 43篇 |
1992年 | 50篇 |
1991年 | 71篇 |
1990年 | 33篇 |
1989年 | 42篇 |
1988年 | 46篇 |
1987年 | 53篇 |
1986年 | 29篇 |
1985年 | 27篇 |
1984年 | 29篇 |
1983年 | 32篇 |
1982年 | 17篇 |
1980年 | 16篇 |
1979年 | 25篇 |
1978年 | 22篇 |
1977年 | 17篇 |
1976年 | 16篇 |
1975年 | 27篇 |
1973年 | 21篇 |
1972年 | 267篇 |
1971年 | 288篇 |
1970年 | 19篇 |
1965年 | 23篇 |
1962年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Jacek Kęsy Beata Maciejewska Magdalena Sowa Magdalena Szumilak Krzysztof Kawałowski Maja Borzuchowska Jan Kopcewicz 《Plant Growth Regulation》2008,55(1):43-50
It has been shown that both IAA and ethylene application inhibit flower induction in the short-day plant Pharbitis nil. However application of IAA has elevated ethylene production in this plant, as well. Strong enhancement of ethylene production
is also correlated with the night-break effect, which completely inhibits flowering. In order to determine what the role of
IAA and ethylene is in the photoperiodic flower induction in Pharbitis nil, we measured changes in their levels during inductive and non-inductive photoperiods, and the effects of ethylene biosynthesis
and action inhibitors on inhibition of flowering by IAA. Our results have shown that the inhibitory effect of IAA on Pharbitis nil flowering is not physiological but is connected with its effect on ethylene biosynthesis. 相似文献
62.
63.
64.
R483, an atypical, I pilus-determining plasmid, and also R144, a typical one, were shown to suppress the DnaA phenotype by integration into the Escherichia coli chromosome. 相似文献
65.
66.
67.
68.
Genetic and physical characterization of proBA genes of the marine bacterium Vibrio parahaemolyticus
Intracellular proline pools have been implicated in the halotolerance of many organisms. To examine this relationship in a moderately halotolerant marine bacterium, Vibrio parahaemolyticus, proline biosynthesis genes were cloned in various plasmids. Some genetic and structural properties of those genes were examined. Subcloning showed that about 3.1 kilobases of V. parahaemolyticus DNA could complement proA and proB but not proC mutations of Escherichia coli. The same fragment would also complement some Pro- mutants of V. parahaemolyticus. Gamma-delta insertion mutagenesis of this subcloned fragment indicated that proB and proA genes of V. parahaemolyticus might be transcribed from different promoters. Two other genes, phoE and gpt, which map closely to the proBA genes in E. coli, were also found to be in close proximity to the proBA genes of V. parahaemolyticus. 相似文献
69.
70.
Purification and characterization of microsomal glutathione S-transferase produced by Aspergillus ochraceus TS are reported. The isozymes are located in microsomes and were active against 1-chloro-2,4-dinitrobenzene, ethacrynic acid, 1,2-dichloro-4-nitrobenzene, trans-4- phenyl-3-buten-2-one,p-nitrobenzyl chloride and bromosulphophthalein. They were inhibited by N-ethylmaleimide and bromosulphophthalein. The GST isozymes produced by Aspergillus ochraceus TS are indistinguishable in respect of their molecular mass both in native and denatured state. The subunit of the purified protein had an apparent Mr of 11 kDa while molecular mass of the native protein is around 56 kDa. The substrate specificity and pl values of the isozymes were different. The GSTs produced by Aspergillus ochraceus TS fairly share functional properties with mammalian cytosolic isozymes. 相似文献