全文获取类型
收费全文 | 2606篇 |
免费 | 203篇 |
专业分类
2809篇 |
出版年
2022年 | 24篇 |
2021年 | 37篇 |
2020年 | 27篇 |
2019年 | 29篇 |
2018年 | 48篇 |
2017年 | 52篇 |
2016年 | 58篇 |
2015年 | 119篇 |
2014年 | 133篇 |
2013年 | 161篇 |
2012年 | 234篇 |
2011年 | 186篇 |
2010年 | 146篇 |
2009年 | 142篇 |
2008年 | 163篇 |
2007年 | 185篇 |
2006年 | 193篇 |
2005年 | 150篇 |
2004年 | 161篇 |
2003年 | 134篇 |
2002年 | 131篇 |
2001年 | 42篇 |
2000年 | 46篇 |
1999年 | 34篇 |
1998年 | 26篇 |
1997年 | 20篇 |
1996年 | 14篇 |
1995年 | 8篇 |
1994年 | 12篇 |
1993年 | 7篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1981年 | 4篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 5篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有2809条查询结果,搜索用时 0 毫秒
31.
32.
33.
Sandrine Lagarrigue Lisa Martin Farhad Hormozdiari Pierre-Fran?ois Roux Calvin Pan Atila van Nas Olivier Demeure Rita Cantor Anatole Ghazalpour Eleazar Eskin Aldons J. Lusis 《Genetics》2013,195(3):1157-1166
We report an analysis of allele-specific expression (ASE) and parent-of-origin expression in adult mouse liver using next generation sequencing (RNA-Seq) of reciprocal crosses of heterozygous F1 mice from the parental strains C57BL/6J and DBA/2J. We found a 60% overlap between genes exhibiting ASE and putative cis-acting expression quantitative trait loci (cis-eQTL) identified in an intercross between the same strains. We discuss the various biological and technical factors that contribute to the differences. We also identify genes exhibiting parental imprinting and complex expression patterns. Our study demonstrates the importance of biological replicates to limit the number of false positives with RNA-Seq data. 相似文献
34.
Benoit Marteyn Samer Sakr Sandrine Farci Mariette Bedhomme Solenne Chardonnet Paulette Decottignies Stéphane D. Lemaire Corinne Cassier-Chauvat Franck Chauvat 《Journal of bacteriology》2013,195(18):4138-4145
In a continuing effort to analyze the selectivity/redundancy of the three glutaredoxin (Grx) enzymes of the model cyanobacterium Synechocystis PCC6803, we have characterized an enzyme system that plays a crucial role in protection against two toxic metal pollutants, mercury and uranium. The present data show that Grx1 (Slr1562 in CyanoBase) selectively interacts with the presumptive mercuric reductase protein (Slr1849). This MerA enzyme plays a crucial role in cell defense against both mercuric and uranyl ions, in catalyzing their NADPH-driven reduction. Like MerA, Grx1 operates in cell protection against both mercury and uranium. The Grx1-MerA interaction requires cysteine 86 (C86) of Grx1 and C78 of MerA, which is critical for its reductase activity. MerA can be inhibited by glutathionylation and subsequently reactivated by Grx1, likely through deglutathionylation. The two Grx1 residues C31, which belongs to the redox active site (CX2C), and C86, which operates in MerA interactions, are both required for reactivation of MerA. These novel findings emphasize the role of glutaredoxins in tolerance to metal stress as well as the evolutionary conservation of the glutathionylation process, so far described mostly for eukaryotes. 相似文献
35.
Frédéric Plewniak Sandrine Koechler Benjamin Navet Éric Dugat‐Bony Olivier Bouchez Pierre Peyret Fabienne Séby Fabienne Battaglia‐Brunet Philippe N. Bertin 《Molecular ecology》2013,22(19):4870-4883
Microorganisms dwelling in sediments have a crucial role in biogeochemical cycles and are expected to have a strong influence on the cycle of arsenic, a metalloid responsible for severe water pollution and presenting major health risks for human populations. We present here a metagenomic study of the sediment from two harbours on the Mediterranean French coast, l'Estaque and St Mandrier. The first site is highly polluted with arsenic and heavy metals, while the arsenic concentration in the second site is below toxicity levels. The goal of this study was to elucidate the potential impact of the microbial community on the chemical parameters observed in complementary geochemical studies performed on the same sites. The metagenomic sequences, along with those from four publicly available metagenomes used as control data sets, were analysed with the RAMMCAP workflow. The resulting functional profiles were compared to determine the over‐represented Gene Ontology categories in the metagenomes of interest. Categories related to arsenic resistance and dissimilatory sulphate reduction were over‐represented in l'Estaque. More importantly, despite very similar profiles, the identification of specific sequence markers for sulphate‐reducing bacteria and sulphur‐oxidizing bacteria showed that sulphate reduction was significantly more associated with l'Estaque than with St Mandrier. We propose that biotic sulphate reduction, arsenate reduction and fermentation may together explain the higher mobility of arsenic observed in l'Estaque in previous physico‐chemical studies of this site. This study also demonstrates that it is possible to draw sound conclusions from comparing complex and similar unassembled metagenomes at the functional level, even with very low sequence coverage. 相似文献
36.
37.
Jadwiga Handzlik Ewa Szymańska Sandrine Alibert Jacqueline Chevalier Ewa Otrębska Elżbieta Pękala Jean-Marie Pagès Katarzyna Kieć-Kononowicz 《Bioorganic & medicinal chemistry》2013,21(1):135-145
A series of amine-alkyl derivatives of 5-arylidenehydantoin 3–21 was evaluated for their ability to improve antibiotic effectiveness in two strains of Gram-negative Enterobacter aerogenes: the reference strain (ATCC-13048) and the chloramphenicol-resistant derivative over-producing the AcrAB-TolC efflux pump (CM-64). Three antibiotics, chloramphenicol, nalidixic acid and sparfloxacin were used as markers of efflux pump activity. New compounds (5–16) were obtained within 3–4 step synthesis using Knoevenagel condensation, Mitsunobu reaction and microwave aided N-alkylation. Molecular modeling based structure–activity relationship (SAR) studies were performed. The most active compounds: (Z)-5-(4-(diethylamino)benzylidene)-3-(2-hydroxy-3-(4-(2-hydroxyethyl)piperazin-1-yl)propyl)imidazolidine-2,4-dione (14) and (Z)-5-(2,4-dimethoxybenzylidene)-3-(2-hydroxy-3-(isopropylamino)propyl)imidazolidine-2,4-dione (15) induced fourfold decrease of minimal inhibition concentration (MIC) of all tested antibiotics in the strain CM-64 overexpressing the AcrAB-TolC pump. 相似文献
38.
39.
Johannes Penner Gilbert B. Adum Matthew T. McElroy Thomas Doherty-Bone Mareike Hirschfeld Laura Sandberger Ché Weldon Andrew A. Cunningham Torsten Ohst Emma Wombwell Daniel M. Portik Duncan Reid Annika Hillers Caleb Ofori-Boateng William Oduro J?rg Pl?tner Annemarie Ohler Adam D. Leaché Mark-Oliver R?del 《PloS one》2013,8(2)
A putative driver of global amphibian decline is the panzootic chytrid fungus Batrachochytrium dendrobatidis (Bd). While Bd has been documented across continental Africa, its distribution in West Africa remains ambiguous. We tested 793 West African amphibians (one caecilian and 61 anuran species) for the presence of Bd. The samples originated from seven West African countries - Bénin, Burkina Faso, Côte d''Ivoire, Ghana, Guinea, Liberia, Sierra Leone - and were collected from a variety of habitats, ranging from lowland rainforests to montane forests, montane grasslands to humid and dry lowland savannahs. The species investigated comprised various life-history strategies, but we focused particularly on aquatic and riparian species. We used diagnostic PCR to screen 656 specimen swabs and histology to analyse 137 specimen toe tips. All samples tested negative for Bd, including a widespread habitat generalist Hoplobatrachus occipitalis which is intensively traded on the West African food market and thus could be a potential dispersal agent for Bd. Continental fine-grained (30 arc seconds) environmental niche models suggest that Bd should have a broad distribution across West Africa that includes most of the regions and habitats that we surveyed. The surprising apparent absence of Bd in West Africa indicates that the Dahomey Gap may have acted as a natural barrier. Herein we highlight the importance of this Bd-free region of the African continent - especially for the long-term conservation of several threatened species depending on fast flowing forest streams (Conraua alleni (“Vulnerable”) and Petropedetes natator (“Near Threatened”)) as well as the “Critically Endangered” viviparous toad endemic to the montane grasslands of Mount Nimba (Nimbaphrynoides occidentalis). 相似文献
40.