全文获取类型
收费全文 | 1155646篇 |
免费 | 126062篇 |
国内免费 | 827篇 |
专业分类
1282535篇 |
出版年
2018年 | 10854篇 |
2017年 | 10262篇 |
2016年 | 14779篇 |
2015年 | 19917篇 |
2014年 | 23459篇 |
2013年 | 33769篇 |
2012年 | 37599篇 |
2011年 | 38154篇 |
2010年 | 25916篇 |
2009年 | 23840篇 |
2008年 | 33639篇 |
2007年 | 34638篇 |
2006年 | 32666篇 |
2005年 | 31523篇 |
2004年 | 31182篇 |
2003年 | 29891篇 |
2002年 | 29000篇 |
2001年 | 53663篇 |
2000年 | 53841篇 |
1999年 | 42714篇 |
1998年 | 15002篇 |
1997年 | 15708篇 |
1996年 | 14645篇 |
1995年 | 13675篇 |
1994年 | 13260篇 |
1993年 | 13139篇 |
1992年 | 34943篇 |
1991年 | 33885篇 |
1990年 | 32961篇 |
1989年 | 32019篇 |
1988年 | 29721篇 |
1987年 | 27917篇 |
1986年 | 25960篇 |
1985年 | 25738篇 |
1984年 | 21440篇 |
1983年 | 17969篇 |
1982年 | 13679篇 |
1981年 | 12283篇 |
1980年 | 11553篇 |
1979年 | 19701篇 |
1978年 | 15330篇 |
1977年 | 13935篇 |
1976年 | 12676篇 |
1975年 | 14035篇 |
1974年 | 15095篇 |
1973年 | 14849篇 |
1972年 | 13425篇 |
1971年 | 12232篇 |
1970年 | 10519篇 |
1969年 | 10084篇 |
排序方式: 共有10000条查询结果,搜索用时 6 毫秒
981.
982.
983.
984.
985.
M Janowski L Baugnet-Mahiec J Merregaert L de Saint-Georges A Sassen J N Ihle J R Maisin 《Comptes rendus des séances de la Société de biologie et de ses filiales》1980,174(5):832-839
Two distinct rat propagates of a radiation leukemia virus (RadLV-Rs) from the C57BL mouse respectively induced characteristic leukemogenic effects. These were found to be related with the infection titers of the isolates, but not with either their antigenic specificities or their viral and proviral genome sequences. 相似文献
986.
Microsporidia 2003: IWOP-8 总被引:1,自引:0,他引:1
LOUIS M. WEISS 《The Journal of eukaryotic microbiology》2003,50(S1):566-568
987.
On the measurement of growth with applications to the modelling and analysis of plant growth 总被引:3,自引:0,他引:3
M. L. Roderick 《Functional ecology》2000,14(2):244-251
988.
Human long-latency auditory evoked potentials were studied during simulation with variable-amplitude pulse sequences from a sound source moving to and from the subject. The N1 peak parameters were shown to depend on an accurate estimate of the direction of the change in the distance to the sound source. Differences in the processing of signals that simulated the approaching and/or distancing of the sound source were found in the N1 and P2 component parameters of on- and off-responses as was a more pronounced long negative potential shift in the evoked response to the approaching source as compared to the distancing source. 相似文献
989.
990.
Yeast cell mortality related to a high-pressure shift: occurrence of cell membrane permeabilization 总被引:3,自引:0,他引:3
The shrinkage of yeast cells caused by high-pressure treatment (250 MPa, 15 min) was investigated using direct microscopic observation. A viable staining method after treatment allowed the volume variation of two populations to be distinguished: an irreversible volume decrease (about 35% of the initial volume) of pressure-inactivated cells during pressure holding time, and viable cells, which were less affected. A mass transfer was then induced during high-pressure treatment. Causes of this transfer seem to be related to a pressure-induced membrane permeabilization, allowing a subsequent leakage of internal solutes, where three ions (Na+, K+ and Ca2+), plus endogenous glycerol, were verified. This glycerol leakage was found to occur after yeast pressurization in a medium having low water activity, although the yeast was not inactivated. All these observations lead to the hypothesis that pressure-induced cell permeabilization could be the cause of yeast inactivation under pressure. 相似文献