全文获取类型
收费全文 | 562篇 |
免费 | 41篇 |
出版年
2022年 | 6篇 |
2021年 | 7篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 19篇 |
2014年 | 19篇 |
2013年 | 21篇 |
2012年 | 20篇 |
2011年 | 18篇 |
2010年 | 13篇 |
2009年 | 10篇 |
2008年 | 22篇 |
2007年 | 15篇 |
2006年 | 17篇 |
2005年 | 12篇 |
2004年 | 16篇 |
2003年 | 16篇 |
2002年 | 17篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 10篇 |
1998年 | 5篇 |
1994年 | 9篇 |
1990年 | 6篇 |
1979年 | 6篇 |
1977年 | 9篇 |
1973年 | 8篇 |
1972年 | 5篇 |
1971年 | 5篇 |
1970年 | 7篇 |
1969年 | 12篇 |
1968年 | 11篇 |
1967年 | 10篇 |
1966年 | 6篇 |
1965年 | 12篇 |
1964年 | 7篇 |
1963年 | 9篇 |
1961年 | 7篇 |
1960年 | 8篇 |
1959年 | 15篇 |
1958年 | 10篇 |
1957年 | 6篇 |
1956年 | 8篇 |
1955年 | 8篇 |
1954年 | 4篇 |
1953年 | 12篇 |
1951年 | 7篇 |
1950年 | 6篇 |
1949年 | 5篇 |
排序方式: 共有603条查询结果,搜索用时 15 毫秒
551.
552.
Nichola J. Hill Michelle L. Power Elizabeth M. Deane 《European Journal of Wildlife Research》2009,55(3):313-316
Ross River virus (RRV) is a mosquito-transmitted Alphavirus emerging in urban centres throughout Australia. The Common brushtail
possum (Trichosurus vulpecula), a native marsupial that has successfully adapted to human settlement, has been implicated as a maintenance reservoir for
RRV. In the present study, RRV exposure was assessed amongst 72 urban-adapted possums from Northern Sydney and ten possums
from a woodland area, remote from urbanisation. Serological screening was performed using an enzyme-linked immunosorbent assay
to detect RRV antibodies in possum sera. Findings indicated that both possum populations from urban and woodland habitats
were negative for the presence of RRV antibodies. Lack of exposure to RRV highlights that the host status of possums is contingent
upon factors other than their abundance and proximity to human settlement. In view of the potential for climate change to
favour transmission of mosquito-borne disease in Australia, identification of wildlife populations entirely absent of RRV
may prove useful for monitoring the predicted spread of the virus. 相似文献
553.
554.
F W Cope 《Physiological chemistry and physics》1977,9(6):547-553
Modern experimental evidence indicates that the cell should be regarded as analogous to an ion exchanger resin granule with structured water in the interstices and with potassium and sodium ions associated with fixed negative charges on the protein matrix. In tissues damaged by disease or trauma, a similar set of changes in properties of cell cations and water is to be expected, for which a similar set of therapies is appropriate. Tissue damage causes a configurational change of the protein matrix from the normal to the damaged state. This leads to loss of association preference for potassium vs. sodium ions and to loss of water structuring, resulting in replacement of cell potassium by sodium and abnormal uptake of water by the cell. Appropriate therapies for reestablishment of the normal configurational state of the proteins of the cell are reestablishment of normal cell ATP production, for which prostaglandin PGBx is the rational approach, plus diets or drugs that decrease sodium and/or increase potassium concentrations in the body. Partial normalization of cell protein configuration by digitalis compounds may also be possible. 相似文献
555.
Anne-Marie Carey Kirsty Hacking Nichola Picken Suvi Honkanen Sharon Kelly Dariusz M. Niedzwiedzki Robert E. Blankenship Yuuki Shimizu Zheng-Yu Wang-Otomo Richard J. Cogdell 《BBA》2014
This study systematically investigated the different types of LH2 produced by Allochromatium (Alc.) vinosum, a photosynthetic purple sulphur bacterium, in response to variations in growth conditions. Three different spectral forms of LH2 were isolated and purified, the B800-820, B800-840 and B800-850 LH2 types, all of which exhibit an unusual split 800 peak in their low temperature absorption spectra. However, it is likely that more forms are also present. Relatively more B800-820 and B800-840 are produced under low light conditions, while relatively more B800-850 is produced under high light conditions. Polypeptide compositions of the three different LH2 types were determined by a combination of HPLC and TOF/MS. The B800-820, B800-840 and B800-850 LH2 types all have a heterogeneous polypeptide composition, containing multiple types of both α and β polypeptides, and differ in their precise polypeptide composition. They all have a mixed carotenoid composition, containing carotenoids of the spirilloxanthin series. In all cases the most abundant carotenoid is rhodopin; however, there is a shift towards carotenoids with a higher conjugation number in LH2 complexes produced under low light conditions. CD spectroscopy, together with the polypeptide analysis, demonstrates that these Alc. vinosum LH2 complexes are more closely related to the LH2 complex from Phs. molischianum than they are to the LH2 complexes from Rps. acidophila. 相似文献
556.
557.
558.
559.
560.