全文获取类型
收费全文 | 31351篇 |
免费 | 2763篇 |
国内免费 | 25篇 |
专业分类
34139篇 |
出版年
2023年 | 161篇 |
2022年 | 367篇 |
2021年 | 776篇 |
2020年 | 415篇 |
2019年 | 549篇 |
2018年 | 654篇 |
2017年 | 537篇 |
2016年 | 965篇 |
2015年 | 1631篇 |
2014年 | 1709篇 |
2013年 | 1999篇 |
2012年 | 2632篇 |
2011年 | 2679篇 |
2010年 | 1632篇 |
2009年 | 1353篇 |
2008年 | 2009篇 |
2007年 | 1985篇 |
2006年 | 1930篇 |
2005年 | 1655篇 |
2004年 | 1679篇 |
2003年 | 1476篇 |
2002年 | 1439篇 |
2001年 | 275篇 |
2000年 | 201篇 |
1999年 | 264篇 |
1998年 | 298篇 |
1997年 | 214篇 |
1996年 | 197篇 |
1995年 | 167篇 |
1994年 | 149篇 |
1993年 | 143篇 |
1992年 | 114篇 |
1991年 | 140篇 |
1990年 | 102篇 |
1989年 | 92篇 |
1988年 | 82篇 |
1987年 | 66篇 |
1986年 | 82篇 |
1985年 | 89篇 |
1984年 | 92篇 |
1983年 | 92篇 |
1982年 | 111篇 |
1981年 | 110篇 |
1980年 | 87篇 |
1979年 | 60篇 |
1978年 | 45篇 |
1977年 | 45篇 |
1976年 | 47篇 |
1975年 | 46篇 |
1974年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
75.
76.
77.
Andrew M. Smith 《Journal of experimental marine biology and ecology》1992,160(2):205-220
The attachment mechanism used by limpets in the rocky, wave-swept intertidal zone of California was determined during high tide and low tide. The two mechanisms that limpets are known to use, suction and glue-like adhesion, were distinguished by measuring the limpets' attachment forces in shear and by staining for glue-like residues where the limpets had been attached. The results show that ≈ 73% of limpets at high tide use suction, while the rest use glue-like adhesion. Conversely, ≈ 75% of limpets at low tide use glue-like adhesion, while the rest use suction. The normal tenacity of limpets was also measured at high and low tide. The mean tenacity at high tide was significantly less than that at low tide. From these data it was estimated that the mean tenacity of glue-like adhesion is ≈ 0.23 MN·m−2 and the mean tenacity of suction adhesion is ≈ 0.09 MN·m−2. It is hypothesized that the cycle of alternating attachment mechanisms is linked to the limpets foraging cycles. 相似文献
78.
Summary Culture conditions have been optimised to enable resting cell cultures ofAcinetobacter calcoaceticus NCIMB 9871 to selectively undertake either oxidative or reductive biotransformations of various bicyclic ketones. 相似文献
79.
Porphyrins and corrins have been immobilized onto solid-phase supports and used to dehalogenate organohalides under reducing conditions. One such system has been used to dehalogenate an aqueous solution (10 ppm) of lindane for over 90 days at over 98% efficiency and for a further 150 days in excess of 65% efficiency. Dichloromethane has been shown to be effectively dehalogenated when supplied to immobilized systems in gaseous form.
Correspondence to: T. S. Marks 相似文献
80.
Evidence is presented for the passive release of monoclonal antibodies (MCAB) from hybridoma cells grown in either batch or continuous-flow culture. This release is promoted at room temperature. Passively released MCAB is indistinguishable from that released by actively growing cells, as judged by SDS-polyacrylamide gel electrophoresis. The significance of these observations in relation to the continuous culture of hybridoma cells is discussed.Maximum MCAB content of TB/C3 hybridoma cells is about 55pg per cell, any additional MCAB produced is secreted.Abbreviations MCAB
monoclonal antibodies
- PBS
phosphate buffered saline
- RT
room temperature
- SDS
sodium dodecyl sulphate 相似文献