全文获取类型
收费全文 | 1083篇 |
免费 | 68篇 |
出版年
2021年 | 8篇 |
2019年 | 6篇 |
2018年 | 13篇 |
2017年 | 5篇 |
2016年 | 13篇 |
2015年 | 31篇 |
2014年 | 28篇 |
2013年 | 113篇 |
2012年 | 64篇 |
2011年 | 73篇 |
2010年 | 36篇 |
2009年 | 38篇 |
2008年 | 68篇 |
2007年 | 69篇 |
2006年 | 76篇 |
2005年 | 60篇 |
2004年 | 63篇 |
2003年 | 64篇 |
2002年 | 60篇 |
2001年 | 18篇 |
2000年 | 22篇 |
1999年 | 11篇 |
1998年 | 13篇 |
1997年 | 10篇 |
1996年 | 9篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 12篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 16篇 |
1988年 | 12篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1984年 | 13篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1977年 | 8篇 |
1976年 | 7篇 |
1974年 | 3篇 |
1967年 | 2篇 |
1964年 | 2篇 |
1963年 | 2篇 |
1959年 | 4篇 |
排序方式: 共有1151条查询结果,搜索用时 15 毫秒
1.
Austin A. Robinson Kevin Ikuta Jonathan Soverow 《The Yale journal of biology and medicine》2014,87(2):199-206
Few prospective studies support the use of anticoagulation during the acute phase of ischemic stroke, though observational data suggest a role in certain populations. Depending on the mechanism of stroke, systemic anticoagulation may prevent recurrent cerebral infarction, but concomitantly carries a risk of hemorrhagic transformation. In this article, we describe a case where anticoagulation shows promise for ischemic stroke and review the evidence that has discredited its use in some circumstances while showing its potential in others. 相似文献
2.
3.
Kunitoshi Yamanaka Teru Ogura Kazuyoshi Murata Toshinobu Suzaki Hironori Niki Sota Hiraga 《FEMS microbiology letters》1994,116(1):61-66
Abstract The smbA gene of Escherichia coli is essential for cell proliferation. The smbA2 mutant shows cold-sensitive colony formation at 22°C. A novel morphological phenotype, formation of a translucent segment at midcell or at a cell pole, was observed by phase-contrastt microscopy at a high frequency in the smbA2 mutant cells incubated in L medium lacking NaCl at 22°C, but not observed in L medium containing 1% NaCl or 20% sucrose at the same temperature. No translucent segment was observed in the wild-type cells in any of the media used. Electron microscopic observation revealed that the translucent segments resulted from the enlargement of a periplasmic space by separation of the inner membrane from the peptidoglycan layer and the outer membrane. 相似文献
4.
5.
Walter Soares Leal Yasumasa Kuwahara Takahisa Suzuki Kazuyoshi Kurosa 《Bioscience, biotechnology, and biochemistry》2013,77(10):2703-2709
The stored-product mite Suidasia medanensis has been found in human-provided habitats in Japan. The mite uses neral as the alarm pheromone, and also secretes (Z,E)- and (£,£)-farnesal, which were isolated from an astigmatid mite for the first time. On the other hand, S. medanensis is the only mite out of fifteen species investigated so far that does not secrete volatile hydrocarbons along with the alarm pheromone, though 9-nonadecene and 6,9-nonadecadiene were found in a hexane extract of the mite. GC-MS, JH-NMR and 13C-NMR of the four isomers of synthetic farnesal, which were isolated by LC and preparative GLC, cleared up some confusion in the literature concerning the stereochemistry of this sesquiterpenoid. 相似文献
6.
7.
Tadao Kunihiro Bart Veuger Diana Vasquez-Cardenas Lara Pozzato Marie Le Guitton Kazuyoshi Moriya Michinobu Kuwae Koji Omori Henricus T. S. Boschker Dick van Oevelen 《PloS one》2014,9(4)
Phospholipid-derived fatty acids (PLFA) and respiratory quinones (RQ) are microbial compounds that have been utilized as biomarkers to quantify bacterial biomass and to characterize microbial community structure in sediments, waters, and soils. While PLFAs have been widely used as quantitative bacterial biomarkers in marine sediments, applications of quinone analysis in marine sediments are very limited. In this study, we investigated the relation between both groups of bacterial biomarkers in a broad range of marine sediments from the intertidal zone to the deep sea. We found a good log-log correlation between concentrations of bacterial PLFA and RQ over several orders of magnitude. This relationship is probably due to metabolic variation in quinone concentrations in bacterial cells in different environments, whereas PLFA concentrations are relatively stable under different conditions. We also found a good agreement in the community structure classifications based on the bacterial PLFAs and RQs. These results strengthen the application of both compounds as quantitative bacterial biomarkers. Moreover, the bacterial PLFA- and RQ profiles revealed a comparable dissimilarity pattern of the sampled sediments, but with a higher level of dissimilarity for the RQs. This means that the quinone method has a higher resolution for resolving differences in bacterial community composition. Combining PLFA and quinone analysis as a complementary method is a good strategy to yield higher resolving power in bacterial community structure. 相似文献
8.
9.
10.
The water-extracted proteins, C and D fractions prepared from defatted soybean meals were fractionated by a method of gel filtration with Sephadex G–200, resulting in higher purification of the C and D components. The dissociated subunits of the C and D components were seen as bands B and B′ on the starch-gel electrophoretical pattern of system without urea. By the starch-gel electrophoresis in system with urea, the subunits of C component were mainly corresponding to the bands 7, 8 and 9, and those of the D component mainly to the band 10. Those subunits were fractionated by column chromatography on DEAE-cellulose contained urea. 相似文献