全文获取类型
收费全文 | 1092篇 |
免费 | 54篇 |
国内免费 | 1篇 |
专业分类
1147篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 9篇 |
2021年 | 18篇 |
2020年 | 8篇 |
2019年 | 18篇 |
2018年 | 22篇 |
2017年 | 11篇 |
2016年 | 22篇 |
2015年 | 52篇 |
2014年 | 66篇 |
2013年 | 65篇 |
2012年 | 126篇 |
2011年 | 86篇 |
2010年 | 64篇 |
2009年 | 51篇 |
2008年 | 75篇 |
2007年 | 80篇 |
2006年 | 89篇 |
2005年 | 68篇 |
2004年 | 60篇 |
2003年 | 50篇 |
2002年 | 36篇 |
2001年 | 9篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 6篇 |
1997年 | 9篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1933年 | 4篇 |
排序方式: 共有1147条查询结果,搜索用时 15 毫秒
1.
2.
Markus Hoffmann Nadine Krüger Pawel Zmora Florian Wrensch Georg Herrler Stefan P?hlmann 《PloS one》2016,11(3)
New World bats have recently been discovered to harbor influenza A virus (FLUAV)-related viruses, termed bat-associated influenza A-like viruses (batFLUAV). The internal proteins of batFLUAV are functional in mammalian cells. In contrast, no biological functionality could be demonstrated for the surface proteins, hemagglutinin (HA)-like (HAL) and neuraminidase (NA)-like (NAL), and these proteins need to be replaced by their human counterparts to allow spread of batFLUAV in human cells. Here, we employed rhabdoviral vectors to study the role of HAL and NAL in viral entry. Vectors pseudotyped with batFLUAV-HAL and -NAL were able to enter bat cells but not cells from other mammalian species. Host cell entry was mediated by HAL and was dependent on prior proteolytic activation of HAL and endosomal low pH. In contrast, sialic acids were dispensable for HAL-driven entry. Finally, the type II transmembrane serine protease TMPRSS2 was able to activate HAL for cell entry indicating that batFLUAV can utilize human proteases for HAL activation. Collectively, these results identify viral and cellular factors governing host cell entry driven by batFLUAV surface proteins. They suggest that the absence of a functional receptor precludes entry of batFLUAV into human cells while other prerequisites for entry, HAL activation and protonation, are met in target cells of human origin. 相似文献
3.
The time dependence of the human
1-antitrypsin polymerization process was studied by means of the intrinsic fluorescence stopped-flow technique as well as the fluorescence-quenching-resolved spectra (FQRS) method and native PAGE. The polymerization was induced by mild denaturing conditions (1 M GuHCl) and temperature. The data show that the dimer formation reaction under mild conditions was followed by an increase of fluorescence intensity. This phenomenon is highly temperature sensitive. The structure of
1-antitrypsin dimer resembles the conformation of antithrombin III dimer. In the presence of the denaturant the polymerization process is mainly limited to the dimer state. The
1-antitrypsin activity measurements confirm monomer-to-dimer transition under these conditions. These results are in contrast to the polymerization process induced by temperature, where the dimer state is an intermediate step leading to long-chain polymers. On the basis of stopped-flow and electrophoretic data it is suggested that both C-sheet as well as A-sheet mechanisms contribute to the polymerization process under mild conditions.Abbreviations GuHCL
guanidinium hydrochloride
- RSL
reactive site loop
- PAI-1
plasminogen activator inhibitor type 1
- AT III
antithrombin III
- FQRS
fluorescence quenching resolved spectra 相似文献
4.
Pawel Palkiewicz† Henk Zwiers† Fritz L. Lorscheider† 《Journal of neurochemistry》1994,62(5):2049-2052
Abstract: ADP-ribosylation is an essential process in the metabolism of brain neuronal proteins, including the regulation of assembly and disassembly of biological polymers. Here, we examine the effect of HgCl2 exposure on the ADP-ribosylation of tubulin and actin, both cytoskeletal proteins also found in neurons, and B-50/43-kDa growth-associated protein (B-50/GAP-43), a neuronal tissue-specific phosphoprotein. In rats we demonstrate, with both in vitro and in vivo experiments, that HgCl2 markedly inhibits the ADP-ribosylation of tubulin and actin. This is direct quantitative evidence that HgCl2, a toxic xenobiotic, alters specific neurochemical reactions involved in maintaining brain neuron structure. 相似文献
5.
Soldati Adrian Muhumuza Geresomu Dezecache Guillaume Fedurek Pawel Taylor Derry Call Josep Zuberbühler Klaus 《International journal of primatology》2023,44(1):116-139
International Journal of Primatology - Observations of early vocal behaviours in non-human primates (hereafter primates) are important for direct comparisons between human and primate vocal... 相似文献
6.
Incubation of human T cells for 18 hr with prostaglandin E2 (PGE2 3 × 10?6M) causes a slight but significant increase in the percentage of Tγ cells and a reduction in Tμ cells. When PGE was added to “non-Tγ” cells, the increase in the percentage of Tγ cells was more marked (from 1.5% Tγ without PGE to 11% Tγ with PGE2, P < 0.001). Supernates from cultures of human monocytes also caused an increase in Tγ cells (10% Tγ without supernate to 18% with supernate, P < 0.01), and this increase was blocked if the monocytes were cultured with indomethacin, a prostaglandin synthetase inhibitor (9% Tγ cells). Thus, monocytes may regulate Fcγ receptors on T cells via PGE2 production. 相似文献
7.
MOFOID is a new server developed mainly for automated modeling of protein structures by their homology to the structures deposited in the PDB database. Selection of a template and calculation of the alignment is performed with the Smith-Waterman or Needleman-Wunsch algorithms implemented in the EMBOSS package. The final model is built and optimised with programs from the JACKAL package. The wide spectrum of options in the web-based interface and the possibility of uploading user's own alignment make MOFOID a suitable platform for testing new approaches in the alignment building. The server is available at https:// valis.ibb.waw.pl/mofoid/. 相似文献
8.
Zhu Y Carragher B Glaeser RM Fellmann D Bajaj C Bern M Mouche F de Haas F Hall RJ Kriegman DJ Ludtke SJ Mallick SP Penczek PA Roseman AM Sigworth FJ Volkmann N Potter CS 《Journal of structural biology》2004,145(1-2):3-14
Manual selection of single particles in images acquired using cryo-electron microscopy (cryoEM) will become a significant bottleneck when datasets of a hundred thousand or even a million particles are required for structure determination at near atomic resolution. Algorithm development of fully automated particle selection is thus an important research objective in the cryoEM field. A number of research groups are making promising new advances in this area. Evaluation of algorithms using a standard set of cryoEM images is an essential aspect of this algorithm development. With this goal in mind, a particle selection "bakeoff" was included in the program of the Multidisciplinary Workshop on Automatic Particle Selection for cryoEM. Twelve groups participated by submitting the results of testing their own algorithms on a common dataset. The dataset consisted of 82 defocus pairs of high-magnification micrographs, containing keyhole limpet hemocyanin particles, acquired using cryoEM. The results of the bakeoff are presented in this paper along with a summary of the discussion from the workshop. It was agreed that establishing benchmark particles and using bakeoffs to evaluate algorithms are useful in promoting algorithm development for fully automated particle selection, and that the infrastructure set up to support the bakeoff should be maintained and extended to include larger and more varied datasets, and more criteria for future evaluations. 相似文献
9.
10.
A range of phenolic compounds were found in leaves of three cotton species. Water and nutrient stress (sulfur deficiency) both caused a significant decrease in phenolic content. Possible interpretations of the observed phenomena are given. 相似文献