首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   443篇
  国内免费   7篇
  完全免费   43篇
  2019年   1篇
  2018年   6篇
  2017年   6篇
  2016年   12篇
  2015年   5篇
  2014年   4篇
  2013年   11篇
  2012年   6篇
  2011年   13篇
  2010年   5篇
  2009年   22篇
  2008年   16篇
  2007年   26篇
  2006年   18篇
  2005年   23篇
  2004年   34篇
  2003年   27篇
  2002年   28篇
  2001年   17篇
  2000年   20篇
  1999年   26篇
  1998年   28篇
  1997年   21篇
  1996年   16篇
  1995年   11篇
  1994年   12篇
  1993年   16篇
  1992年   15篇
  1991年   11篇
  1990年   11篇
  1989年   10篇
  1988年   3篇
  1987年   5篇
  1986年   1篇
  1984年   3篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1978年   1篇
排序方式: 共有493条查询结果,搜索用时 109 毫秒
1.
Oligosaccharins: structures and signal transduction   总被引:33,自引:0,他引:33  
2.
3.
在南方红豆杉细胞悬浮培养过程中,研究了在指数生长期的末期加入真菌诱导子(尖孢镰刀菌的胞壁组分粗提物)对细胞态势及紫杉醇合成的影响。结果表明,真菌诱导子能在短期内激发细胞的防御性应答反应而产生氧迸发,细胞的氧化还原态势发生了明显的变化,培养基发生碱化现象,表征酶含量的蛋白质含量明显提高,SOD、POD、CAT的活力出现波动性变化,并具有一定的时序性。同时,南方红豆杉悬浮培养体系中产次生代谢途径中重要的酶PAL的活力得到提高,紫杉醇的合成被加强,产量得到了显著提高,达到了对照组的5倍左右。  相似文献
4.
5.
The molecular biology of disease resistance   总被引:22,自引:0,他引:22  
6.
7.
Taxus chinensis suspension cells were cultured in the modified Gamborg's B5 medium. Addition of 50 mg chitosan l–1, 60 M methyl jasmonate and 30 M Ag+ resulted in the greatest paclitaxel production, at 25 mg l–1 in the cultures, being almost 40 times higher than that of the control culture, 10 times higher than that of the culture exposed to Ag+, 6 times higher than that of the culture elicited by chitosan and almost double that of the culture elicited by methyl jasmonate.  相似文献
8.
The Origin of the Oxidative Burst in Plants   总被引:18,自引:0,他引:18  
A large number of publications recently have drawn strong analogies between the production of active oxygen species in plant cells and the “oxidative burst” of the phagocyte, even to the point of constructing elaborate models involving receptor mediated G-protein activation of a plasmalemma NADPH oxidase in plant cells. However there are potentially other active oxygen species generating systems at the plant cell surface. The present work examines these alternatives with particular emphasis on the rapid production of active oxygen species, in common with a number of other systems, by suspension-cultured cells of French bean on exposure to an elicitor preparation from the fungal pathogen Colletotrichum lindemuthianum. The cells show a rapid increase in oxygen uptake which is followed shortly afterwards by the appearance of a burst of these active oxygen species, as measured by a luminescence assay, which is probably all accounted for by hydrogen peroxide. An essential factor in this production of H2O2 appears to be a transient alkalinization of the apoplast where the pH rises to 7.0-7.2. Dissipation of this pH change with a number of treatments, including ionophores and strong buffers, substantially inhibits the oxidative burst. Little evidence was found for enhanced activation of a membrane-bound NADPH oxidase. However the production of H2O2 under alkaline conditions can be modelled in vitro with a number of peroxidases, one of which, an Mr 46,000 wall-bound cationic peroxidase, is able to sustain H2O2 production at neutral pH unlike the other peroxidases which only show low levels of this reaction under such conditions and have pH optima at values greater than 8.0. On the basis of such comparative pH profiles between the cells and the purified peroxidase and further inhibition studies a direct production of H2O2 from the wall peroxidase in French bean cells is proposed. These experiments may mimic some of the responses to plant pathogens, particularly the hypersensitive response, which is an important feature of resistance. A cell wall peroxidase-origin for the oxidative burst is clearly different from a model consisting of receptor activation of a plasmaiemma-localised NADPH oxidase generating superoxide. An alternative simple and rapid mechanism thus exists for the generation of H2O2 which does not require such multiple proteinaceous components.  相似文献
9.
寡聚糖诱导的植物抗性信号转导   总被引:17,自引:0,他引:17  
来源于植物及其病原体细胞壁的寡聚糖,可作为激发子诱导植物细胞发生抗性反应,寡聚糖信号被植物细胞识别后,可迅速引起质膜去极化,离子通道开放,胞外培养基碱化等瞬间反应;还可通过硬脂酸代谢途径合成茉莉酸信号分子,诱导抗性相关基因的表达。  相似文献
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号