全文获取类型
收费全文 | 9950篇 |
免费 | 836篇 |
国内免费 | 4篇 |
出版年
2022年 | 43篇 |
2021年 | 116篇 |
2020年 | 71篇 |
2019年 | 86篇 |
2018年 | 164篇 |
2017年 | 204篇 |
2016年 | 311篇 |
2015年 | 436篇 |
2014年 | 474篇 |
2013年 | 596篇 |
2012年 | 770篇 |
2011年 | 776篇 |
2010年 | 454篇 |
2009年 | 391篇 |
2008年 | 585篇 |
2007年 | 582篇 |
2006年 | 542篇 |
2005年 | 560篇 |
2004年 | 482篇 |
2003年 | 432篇 |
2002年 | 416篇 |
2001年 | 167篇 |
2000年 | 179篇 |
1999年 | 149篇 |
1998年 | 61篇 |
1997年 | 54篇 |
1996年 | 50篇 |
1995年 | 47篇 |
1994年 | 40篇 |
1993年 | 39篇 |
1992年 | 72篇 |
1991年 | 79篇 |
1990年 | 49篇 |
1989年 | 86篇 |
1988年 | 68篇 |
1987年 | 60篇 |
1986年 | 53篇 |
1985年 | 57篇 |
1984年 | 52篇 |
1983年 | 56篇 |
1982年 | 45篇 |
1981年 | 44篇 |
1979年 | 42篇 |
1978年 | 34篇 |
1976年 | 45篇 |
1975年 | 40篇 |
1974年 | 56篇 |
1973年 | 43篇 |
1972年 | 36篇 |
1971年 | 42篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
952.
953.
954.
Cyclic lipopeptides from Bacillus subtilis activate distinct patterns of defence responses in grapevine 下载免费PDF全文
Giovanni Farace Olivier Fernandez Lucile Jacquens François Coutte François Krier Philippe Jacques Christophe Clément Essaid Ait Barka Cédric Jacquard Stéphan Dorey 《Molecular Plant Pathology》2015,16(2):177-187
Non‐self‐recognition of microorganisms partly relies on the perception of microbe‐associated molecular patterns (MAMPs) and leads to the activation of an innate immune response. Bacillus subtilis produces three main families of cyclic lipopeptides (LPs), namely surfactins, iturins and fengycins. Although LPs are involved in induced systemic resistance (ISR) activation, little is known about defence responses induced by these molecules and their involvement in local resistance to fungi. Here, we showed that purified surfactin, mycosubtilin (iturin family) and plipastatin (fengycin family) are perceived by grapevine plant cells. Although surfactin and mycosubtilin stimulated grapevine innate immune responses, they differentially activated early signalling pathways and defence gene expression. By contrast, plipastatin perception by grapevine cells only resulted in early signalling activation. Gene expression analysis suggested that mycosubtilin activated salicylic acid (SA) and jasmonic acid (JA) signalling pathways, whereas surfactin mainly induced an SA‐regulated response. Although mycosubtilin and plipastatin displayed direct antifungal activity, only surfactin and mycosubtilin treatments resulted in a local long‐lasting enhanced tolerance to the necrotrophic fungus Botrytis cinerea in grapevine leaves. Moreover, challenge with specific strains overproducing surfactin and mycosubtilin led to a slightly enhanced stimulation of the defence response compared with the LP‐non‐producing strain of B. subtilis. Altogether, our results provide the first comprehensive view of the involvement of LPs from B. subtilis in grapevine plant defence and local resistance against the necrotrophic pathogen Bo. cinerea. Moreover, this work is the first to highlight the ability of mycosubtilin to trigger an immune response in plants. 相似文献
955.
956.
957.
Florent Querini Jean-Christophe Béziat Stéphane Morel Valérie Boch Patrick Rousseaux 《The International Journal of Life Cycle Assessment》2011,16(5):454-464
Purpose
As new alternative automotive fuels are being developed, life cycle assessment (LCA) is being used to assess the sustainability of these new options. A fuel LCA is commonly referred as a “Well To Wheels” analysis and calculates the environmental impacts of producing the fuel (the “Well To Tank” stage) and using it to move a car (the “Tank To Wheels” stage, TTW). The TTW environmental impacts are the main topic of this article. 相似文献958.
Florent Querini Stéphane Morel Valérie Boch Patrick Rousseaux 《The International Journal of Life Cycle Assessment》2011,16(8):829-840
Purpose
In order to provide more sustainable fuels and address the depletion of oil as a feedstock, the automotive industry must adapt to a growing market share of alternative fuels. The environmental impacts of the automotive industry to date would suggest that these alternatives will be more environmentally friendly than petroleum-based fuels. This is nonetheless an assumption that cannot be confirmed without a systematic life cycle assessment (LCA). This article explores the feasibility of USEtox to provide information needed for automotive-fuel LCA. 相似文献959.
Martina Höckner Reinhard Dallinger Stephen R. Stürzenbaum 《Journal of biological inorganic chemistry》2011,16(7):1057-1065
Metallobiologists have, at large, neglected soil dwelling invertebrates; exceptions are the nematode (Caenorhabditis elegans) and snails (Helix pomatia and Cantareus aspersus). This review aims to compare and contrast the molecular, protein and cellular mechanisms of the multifunctional nematode
and snail metallothioneins (MTs). The C. elegans genome contains two MT genes, mtl-1, which is constitutively expressed in the pharynx and likely to act as an essential and/or toxic metal sensor, and mtl-2, which plays a negligible role under normal physiological conditions but is strongly induced (as mtl-1) in intestinal cells upon metal exposure. It has been possible to follow the intricate phenotypic responses upon the knockdown/knockout
of single and multiple MT isoforms and we have started to decipher the multifunctional role of C. elegans MTs. The snails have contributed to our understanding regarding MT evolution and diversity, structure and metal-specific
functionality. The H. pomatia and C. aspersus genomes contain at least three MT isoform genes. CdMT is responsible for cadmium detoxification, CuMT is involved in copper
homeostasis and Cd/CuMT is a putative ancestral MT possibly only of minor importance in metal metabolism. Further investigations
of nematode, snail and other invertebrate MTs will allow the development of alternative biomarker approaches and lead to an
improved understanding of metallobiology, protein evolution and toxicogenomics. 相似文献
960.
Graveline R Mourez M Hancock MA Martin C Boisclair S Harel J 《Molecular microbiology》2011,81(5):1286-1299
F165(1) and the pyelonephritis-associated pili (Pap) are two members of the type P family of adhesive factors that play a key role in the establishment of disease caused by extraintestinal Escherichia coli (ExPEC) strains. They are both under the control of an epigenetic and reversible switch that defines the number of fimbriated (ON) and afimbriated (OFF) cells within a clonal population. Our present study demonstrates that the high level of ON cells found during F165(1) phase variation is due to altered stability of the DNA complex formed by the leucine-responsive regulatory protein (Lrp) at its repressor binding sites 1-3; after each cell cycle, complex formation is also modulated by the local regulator FooI (homologue to PapI) which promotes the transit of Lrp towards its activator binding sites 4-6. Furthermore, we identified two nucleotides (T490, G508) surrounding the Lrp binding site 1 that are critical to maintaining a high OFF to ON switch rate during F165(1) phase variation, as well as switching Pap fimbriae towards the OFF state. 相似文献