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   1679篇
  免费   79篇
  国内免费   1篇
  1759篇
  2024年   3篇
  2023年   20篇
  2022年   44篇
  2021年   74篇
  2020年   40篇
  2019年   48篇
  2018年   66篇
  2017年   59篇
  2016年   72篇
  2015年   96篇
  2014年   103篇
  2013年   138篇
  2012年   160篇
  2011年   132篇
  2010年   66篇
  2009年   62篇
  2008年   77篇
  2007年   79篇
  2006年   46篇
  2005年   42篇
  2004年   41篇
  2003年   39篇
  2002年   31篇
  2001年   19篇
  2000年   17篇
  1999年   11篇
  1998年   8篇
  1997年   9篇
  1996年   4篇
  1995年   9篇
  1994年   7篇
  1993年   9篇
  1992年   12篇
  1991年   14篇
  1990年   17篇
  1989年   10篇
  1988年   7篇
  1987年   7篇
  1986年   4篇
  1985年   9篇
  1984年   4篇
  1982年   3篇
  1981年   3篇
  1980年   3篇
  1978年   4篇
  1977年   3篇
  1976年   3篇
  1975年   3篇
  1959年   2篇
  1958年   4篇
排序方式: 共有1759条查询结果,搜索用时 0 毫秒
21.
Adenovirus Internalization and Infection Require Dynamin   总被引:5,自引:9,他引:5       下载免费PDF全文
The cell receptors that facilitate adenovirus internalization into cells have been identified; however, the infectious pathway of virus entry has not been established. Adenovirus entry and infection were examined in HeLa cells lacking or overexpressing mutant dynamin, a protein that specifically regulates clathrin-mediated endocytosis. Expression of mutant dynamin significantly reduced adenovirus internalization and gene delivery, indicating a functional requirement for this molecule. These findings are consistent with virus entry via the clathrin-coated pit pathway.  相似文献   
22.
23.
24.
Pseudomonas aeruginosa is a metabolically versatile bacterium that is found in a wide range of biotic and abiotic habitats. It is a major human opportunistic pathogen causing numerous acute and chronic infections. The critical traits contributing to the pathogenic potential of P. aeruginosa are the production of a myriad of virulence factors, formation of biofilms and antibiotic resistance. Expression of these traits is under stringent regulation, and it responds to largely unidentified environmental signals. This review is focused on providing a global picture of virulence gene regulation in P. aeruginosa. In addition to key regulatory pathways that control the transition from acute to chronic infection phenotypes, some regulators have been identified that modulate multiple virulence mechanisms. Despite of a propensity for chaotic behaviour, no chaotic motifs were readily observed in the P. aeruginosa virulence regulatory network. Having a ‘birds-eye’ view of the regulatory cascades provides the forum opportunities to pose questions, formulate hypotheses and evaluate theories in elucidating P. aeruginosa pathogenesis. Understanding the mechanisms involved in making P. aeruginosa a successful pathogen is essential in helping devise control strategies.  相似文献   
25.
26.
During the survey of two successive years 2012–2013, in nearby places of Gorakhpur districts, Uttar Pradesh, India, Arundo donax plants were found to be exhibiting witches’ broom, excessive branching accompanied with little leaf symptoms with considerable disease incidence. Nested PCR carried out with universal primers pair R16F2n/R16R2 employing the PCR (P1/P7) product as a template DNA (1:20) resulted in expected size positive amplification ~1.2 kb in all symptom-bearing plants suggested the association of phytoplasma with witches’ broom disease of Narkat plants. BLASTn analysis of the 16S rRNA gene sequence showed the highest (99%) sequence identity with Candidatus phytoplasma asteris (16SrI group). In phylogenetic analysis, the sequence data showed close relationships with the members of 16SrI phytoplasma and clustered within a single clade of 16SrI group and closed to B subgroup representatives. This is a first report of 16Sr I-B group phytoplasma associated with witches’ broom accompanied with little leaf disease of Narkat in India.  相似文献   
27.
International Journal of Peptide Research and Therapeutics - Marine snails are abundant sources of biologically important conopeptides with their potential applications in drug development. The...  相似文献   
28.
Russian Journal of Bioorganic Chemistry - Discovery towards the potent antimicrobial agents is indispensable for the treatment of infections caused by resistant microbes. Thus, we prepared a novel...  相似文献   
29.
Entomopathogenic nematodes and parasitoid larvae of some wasps play important roles in the natural control of the pest insects. However, it has not been excluded that competition between nematodes and wasps may in some cases reduce their efficacy in the pest control. Using caterpillars of Spodoptera littoralis, we examined interactions between the nematode Steinernema carpocapsae and the venom of the parasitoid Habrobracon hebetor. The survival of S. littoralis caterpillars was reduced in a dose-dependent manner when 5 to 500 nematodes or 0.005–0.1 venom units were applied to single caterpillars. High doses of either nematodes or the venom caused death within 1–3 days in all treated hosts. The low doses of nematodes killed caterpillars within a week, in some cases when they attempted to pupate. Caterpillars receiving low venom doses were characterized by extended survival time terminated with death due to starvation. Combined treatment of nematodes and the venom were mutually synergistic and elicited severe lethal effects. The nematodes were fully resistant to the venom and can feed and grow on the symbiotic bacteria in vitro. The venom impairs food processing and causes death of caterpillars due to starvation. Disruption of the hormonal regulation of metamorphosis by ecdysteroids and juvenile hormone could be responsible for defective moults block at different stages of the moulting process, regionally restricted moulting, moults to “intermediates” combining regions of newly secreted larval and pupal cuticles.  相似文献   
30.
Journal of Plant Biochemistry and Biotechnology - Pigeonpea, an important legume crop is a good host plant for lac cultivation in North East India. In the present study, sixty-three polymorphic EST...  相似文献   
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