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   460篇
  免费   20篇
  480篇
  2023年   1篇
  2022年   3篇
  2021年   8篇
  2020年   4篇
  2019年   5篇
  2018年   13篇
  2017年   8篇
  2016年   20篇
  2015年   22篇
  2014年   27篇
  2013年   47篇
  2012年   46篇
  2011年   46篇
  2010年   21篇
  2009年   20篇
  2008年   25篇
  2007年   28篇
  2006年   20篇
  2005年   17篇
  2004年   17篇
  2003年   12篇
  2002年   17篇
  2001年   8篇
  2000年   3篇
  1999年   6篇
  1998年   2篇
  1997年   6篇
  1995年   1篇
  1994年   1篇
  1993年   5篇
  1992年   2篇
  1991年   1篇
  1989年   1篇
  1988年   5篇
  1987年   4篇
  1986年   2篇
  1984年   1篇
  1983年   1篇
  1979年   1篇
  1975年   3篇
排序方式: 共有480条查询结果,搜索用时 15 毫秒
31.
This study reports the introduction of gfp marker in two endophytic bacterial strains (Pantoea agglomerans C33.1, isolated from cocoa, and Enterobacter cloacae PR2/7, isolated from citrus) to monitor the colonization in Madagascar perinwinkle (Catharanthus roseus). Stability of the plasmid encoding gfp was confirmed in vitro for at least 72 h of bacterial growth and after the colonization of tissues, under non-selective conditions. The colonization was observed using fluorescence microscopy and enumeration of culturable endophytes in inoculated perinwinkle plants that grew for 10 and 20 days. Gfp-expressing strains were re-isolated from the inner tissues of surface-sterilized roots and stems of inoculated plants, and the survival of the P. agglomerans C33:1gfp in plants 20 days after inoculation, even in the absence of selective pressure, suggests that is good colonizer. These results indicated that both gfp-tagged strains, especially P. agglomerans C33.1, may be useful tools to deliver enzymes or other proteins in plant.  相似文献   
32.
33.
34.
35.
Transglutaminases (TGs) are a large family of related and ubiquitous enzymes that catalyze post-translational modifications of proteins. The main activity of these enzymes is the cross-linking of a glutaminyl residue of a protein/peptide substrate to a lysyl residue of a protein/peptide co-substrate. In addition to lysyl residues, other second nucleophilic co-substrates may include monoamines or polyamines (to form mono- or bi-substituted /crosslinked adducts) or -OH groups (to form ester linkages). In the absence of co-substrates, the nucleophile may be water, resulting in the net deamidation of the glutaminyl residue. The TG enzymes are also capable of catalyzing other reactions important for cell viability. The distribution and the physiological roles of TG enzymes have been widely studied in numerous cell types and tissues and their roles in several diseases have begun to be identified. "Tissue" TG (TG2), a member of the TG family of enzymes, has definitely been shown to be involved in the molecular mechanisms responsible for a very widespread human pathology: i.e. celiac disease (CD). TG activity has also been hypothesized to be directly involved in the pathogenetic mechanisms responsible for several other human diseases, including neurodegenerative diseases, which are often associated with CD. Neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, supranuclear palsy, Huntington's disease and other recently identified polyglutamine diseases, are characterized, in part, by aberrant cerebral TG activity and by increased cross-linked proteins in affected brains. In this review, we discuss the physio-pathological role of TG-catalyzed reactions, with particular interest in the molecular mechanisms that could involve these enzymes in the physio-pathological processes responsible for human neurodegenerative diseases.  相似文献   
36.
Following our previous research on anti-inflammatory drugs (NSAIDs), we report here the synthesis of chiral 1,5-diarylpyrroles derivatives that were characterized for their in vitro inhibitory effects toward cyclooxygenase (COX) isozymes. Analysis of enzymatic affinity and COX-2 selectivity led us to the selection of one compound (+/-)-10b that was further tested in vitro in the human whole blood (HWB) and in vivo for its anti-inflammatory activity in mice. The affinity data have been rationalized through docking simulations.  相似文献   
37.
Nonspecific binding of anandamide to plastic exhibits many features that could be mistaken as biological processes, thereby representing an important source of conflicting data on the uptake and release of this lipophilic substance. Herein, we propose an improved method to assay anandamide transport, by using glass slides (i.e., coverslips) as physical support to grow cells. Although the results obtained using plastic do not differ significantly from those obtained using glass, the new procedure has the advantage of being faster, simpler, and more accurate. In fact, the lack of aspecific adsorption of anandamide to the glass surface yields a lower background and a higher precision and accuracy in determining transport kinetics, especially for the export process. Remarkably, the kinetic parameters of anandamide uptake obtained with the old and the new procedures may be similar or different depending on the cell type, thus demonstrating the complexity of the interference of plastic on the transport process. In addition, the novel procedure is particularly suitable for visualization and measurement of anandamide transport in intact cells by using a biotinylated derivative in confocal fluorescence microscopy.  相似文献   
38.
Endocrine disruptors are chemicals able to induce adverse effects into wildlife and humans owing to their ability of interfering with the endocrine system. Bisphenol A (BPA) has been chosen as model of endocrine disruptors. To reduce the BPA pollution in waters we proposed the employment of the process of thermodialysis. Two different catalytic membranes have been prepared by covalently immobilizing laccase (from Trametes versicolor) by means of a diazotation process or tyrosinase (from mushroom) by condensation. The support was a nylon membrane. The bioremediation power of both catalytic membranes has been analysed under isothermal and non-isothermal conditions.The advantages in using non-isothermal bioreactors were discussed in terms of reduction of the bioremediation times.  相似文献   
39.
This article documents the addition of 92 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Anopheles minimus, An. sinensis, An. dirus, Calephelis mutica, Lutjanus kasmira, Murella muralis and Orchestia montagui. These loci were cross-tested on the following species: Calephelis arizonensi, Calephelis borealis, Calephelis nemesis, Calephelis virginiensis and Lutjanus bengalensis.  相似文献   
40.
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