全文获取类型
收费全文 | 3084篇 |
免费 | 303篇 |
出版年
2022年 | 22篇 |
2021年 | 56篇 |
2020年 | 24篇 |
2019年 | 25篇 |
2018年 | 37篇 |
2017年 | 41篇 |
2016年 | 88篇 |
2015年 | 150篇 |
2014年 | 148篇 |
2013年 | 164篇 |
2012年 | 247篇 |
2011年 | 230篇 |
2010年 | 177篇 |
2009年 | 144篇 |
2008年 | 165篇 |
2007年 | 176篇 |
2006年 | 160篇 |
2005年 | 147篇 |
2004年 | 174篇 |
2003年 | 152篇 |
2002年 | 149篇 |
2001年 | 54篇 |
2000年 | 41篇 |
1999年 | 58篇 |
1998年 | 52篇 |
1997年 | 30篇 |
1996年 | 22篇 |
1995年 | 25篇 |
1994年 | 30篇 |
1993年 | 33篇 |
1992年 | 38篇 |
1991年 | 28篇 |
1990年 | 37篇 |
1989年 | 32篇 |
1988年 | 27篇 |
1987年 | 16篇 |
1986年 | 18篇 |
1985年 | 17篇 |
1984年 | 15篇 |
1983年 | 12篇 |
1982年 | 13篇 |
1981年 | 12篇 |
1980年 | 8篇 |
1979年 | 11篇 |
1978年 | 11篇 |
1977年 | 9篇 |
1974年 | 7篇 |
1972年 | 6篇 |
1969年 | 6篇 |
1966年 | 8篇 |
排序方式: 共有3387条查询结果,搜索用时 15 毫秒
281.
Tian Fang Qin Wen Zhang Ran Herzschuh Ulrike Ni Jian Zhang Chengjun Mischke Steffen Cao Xianyong 《Vegetation History and Archaeobotany》2022,31(6):549-558
Vegetation History and Archaeobotany - The terrestrial ecosystem in the Yellow River Source Area (YRSA) is sensitive to climate change and human impacts, although past vegetation change and the... 相似文献
282.
Emanuela Zaharieva Irmgard U. Haussmann Ulrike Br?uer Matthias Soller 《Molecular and cellular biology》2015,35(18):3104-3115
Neuronally coexpressed ELAV/Hu proteins comprise a family of highly related RNA binding proteins which bind to very similar cognate sequences. How this redundancy is linked to in vivo function and how gene-specific regulation is achieved have not been clear. Analysis of mutants in Drosophila ELAV/Hu family proteins ELAV, FNE, and RBP9 and of genetic interactions among them indicates that they have mostly independent roles in neuronal development and function but have converging roles in the regulation of synaptic plasticity. Conversely, ELAV, FNE, RBP9, and human HuR bind ELAV target RNA in vitro with similar affinities. Likewise, all can regulate alternative splicing of ELAV target genes in nonneuronal wing disc cells and substitute for ELAV in eye development upon artificially increased expression; they can also substantially restore ELAV''s biological functions when expressed under the control of the elav gene. Furthermore, ELAV-related Sex-lethal can regulate ELAV targets, and ELAV/Hu proteins can interfere with sexual differentiation. An ancient relationship to Sex-lethal is revealed by gonadal expression of RBP9, providing a maternal fail-safe for dosage compensation. Our results indicate that highly related ELAV/Hu RNA binding proteins select targets for mRNA processing through alteration of their expression levels and subcellular localization but only minimally by altered RNA binding specificity. 相似文献
283.
Metabolic and transcriptomic signatures of rice floral organs reveal sugar starvation as a factor in reproductive failure under heat and drought stress 总被引:2,自引:0,他引:2
下载免费PDF全文
![点击此处可从《Plant, cell & environment》网站下载免费的PDF全文](/ch/ext_images/free.gif)
284.
Lars?Thomas Julian?Kahr Peter?Schmidt Ulrike?Krug Holger?A.?Scheidt Daniel?HusterEmail author 《Journal of biomolecular NMR》2015,61(3-4):347-359
In contrast to the static snapshots provided by protein crystallography, G protein-coupled receptors constitute a group of proteins with highly dynamic properties, which are required in the receptors’ function as signaling molecule. Here, the human neuropeptide Y2 receptor was reconstituted into a model membrane composed of monounsaturated phospholipids and solid-state NMR was used to characterize its dynamics. Qualitative static 15N NMR spectra and quantitative determination of 1H–13C order parameters through measurement of the 1H–13C dipolar couplings of the CH, CH2 and CH3 groups revealed axially symmetric motions of the whole molecule in the membrane and molecular fluctuations of varying amplitude from all molecular segments. The molecular order parameters (Sbackbone = 0.59–0.67, SCH2 = 0.41–0.51 and SCH3 = 0.22) obtained in directly polarized 13C NMR experiments demonstrate that the Y2 receptor is highly mobile in the native-like membrane. Interestingly, according to these results the receptor was found to be slightly more rigid in the membranes formed by the monounsaturated phospholipids than by saturated phospholipids as investigated previously. This could be caused by an increased chain length of the monounsaturated lipids, which may result in a higher helical content of the receptor. Furthermore, the incorporation of cholesterol, phosphatidylethanolamine, or negatively charged phosphatidylserine into the membrane did not have a significant influence on the molecular mobility of the Y2 receptor. 相似文献
285.
286.
Carina Knauer Anja K. Dörrich Sebastian Bubendorfer Ulrike Ruppert Gert Bange Kai M. Thormann 《Molecular microbiology》2015,98(4):727-742
Spatiotemporal regulation of cell polarity plays a role in many fundamental processes in bacteria and often relies on ‘landmark’ proteins which recruit the corresponding clients to their designated position. Here, we explored the localization of two multi‐protein complexes, the polar flagellar motor and the chemotaxis array, in Shewanella putrefaciens CN‐32. We demonstrate that polar positioning of the flagellar system, but not of the chemotaxis system, depends on the GTPase FlhF. In contrast, the chemotaxis array is recruited by a transmembrane protein which we identified as the functional ortholog of Vibrio cholerae HubP. Mediated by its periplasmic N‐terminal LysM domain, SpHubP exhibits an FlhF‐independent localization pattern during cell cycle similar to its Vibrio counterpart and also has a role in proper chromosome segregation. In addition, while not affecting flagellar positioning, SpHubP is crucial for normal flagellar function and is involved in type IV pili‐mediated twitching motility. We hypothesize that a group of HubP/FimV homologs, characterized by a rather conserved N‐terminal periplasmic section required for polar targeting and a highly variable acidic cytoplasmic part, primarily mediating recruitment of client proteins, serves as polar markers in various bacterial species with respect to different cellular functions. 相似文献
287.
Identification of NoxD/Pro41 as the homologue of the p22phox NADPH oxidase subunit in fungi
下载免费PDF全文
![点击此处可从《Molecular microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Isabelle Lacaze Hervé Lalucque Ulrike Siegmund Philippe Silar Sylvain Brun 《Molecular microbiology》2015,95(6):1006-1024
NADPH oxidases (Nox) are membrane complexes that produce O2?. Researches in mammals, plants and fungi highlight the involvement of Nox‐generated ROS in cell proliferation, differentiation and defense. In mammals, the core enzyme gp91phox/Nox2 is associated with p22phox forming the flavocytochrome b558 ready for activation by a cytosolic complex. Intriguingly, no homologue of the p22phox gene has been found in fungal genomes, questioning how the flavoenzyme forms. Using whole genome sequencing combined with phylogenetic analysis and structural studies, we identify the fungal p22phox homologue as being mutated in the Podospora anserina mutant IDC509. Functional studies show that the fungal p22phox, PaNoxD, acts along PaNox1, but not PaNox2, a second fungal gp91phox homologue. Finally, cytological analysis of functional tagged versions of PaNox1, PaNoxD and PaNoxR shows clear co‐localization of PaNoxD and PaNox1 and unravel a dynamic assembly of the complex in the endoplasmic reticulum and in the vacuolar system. 相似文献
288.
Kirsten I. Bos Günter J?ger Verena J. Schuenemann ?shild J. V?gene Maria A. Spyrou Alexander Herbig Kay Nieselt Johannes Krause 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2015,370(1660)
DNA capture coupled with next generation sequencing is highly suitable for the study of ancient pathogens. Screening for pathogens can, however, be meticulous when assays are restricted to the enrichment of single organisms, which is common practice. Here, we report on an array-based DNA capture screening technique for the parallel detection of nearly 100 pathogens that could have potentially left behind molecular signatures in preserved ancient tissues. We demonstrate the sensitivity of our method through evaluation of its performance with a library known to harbour ancient Mycobacterium leprae DNA. This rapid and economical technique will be highly useful for the identification of historical diseases that are difficult to characterize based on archaeological information alone. 相似文献
289.
290.
Thomas O. Eichmann Lukas Grumet Ulrike Taschler Jürgen Hartler Christoph Heier Aaron Woblistin Laura Pajed Manfred Kollroser Gerald Rechberger Gerhard G. Thallinger Rudolf Zechner Günter Haemmerle Robert Zimmermann Achim Lass 《Journal of lipid research》2015,56(10):1972-1984
Lipid droplets (LDs) of hepatic stellate cells (HSCs) contain large amounts of vitamin A [in the form of retinyl esters (REs)] as well as other neutral lipids such as TGs. During times of insufficient vitamin A availability, RE stores are mobilized to ensure a constant supply to the body. To date, little is known about the enzymes responsible for the hydrolysis of neutral lipid esters, in particular of REs, in HSCs. In this study, we aimed to identify LD-associated neutral lipid hydrolases by a proteomic approach using the rat stellate cell line HSC-T6. First, we loaded cells with retinol and FAs to promote lipid synthesis and deposition within LDs. Then, LDs were isolated and lipid composition and the LD proteome were analyzed. Among other proteins, we found perilipin 2, adipose TG lipase (ATGL), and comparative gene identification-58 (CGI-58), known and established LD proteins. Bioinformatic search of the LD proteome for α/β-hydrolase fold-containing proteins revealed no yet uncharacterized neutral lipid hydrolases. In in vitro activity assays, we show that rat (r)ATGL, coactivated by rat (r)CGI-58, efficiently hydrolyzes TGs and REs. These findings suggest that rATGL and rCGI-58 are LD-resident proteins in HSCs and participate in the mobilization of both REs and TGs. 相似文献