全文获取类型
收费全文 | 1083037篇 |
免费 | 113786篇 |
国内免费 | 594篇 |
专业分类
1197417篇 |
出版年
2018年 | 9702篇 |
2016年 | 13069篇 |
2015年 | 17150篇 |
2014年 | 20445篇 |
2013年 | 29447篇 |
2012年 | 32858篇 |
2011年 | 33755篇 |
2010年 | 23116篇 |
2009年 | 21389篇 |
2008年 | 30242篇 |
2007年 | 31566篇 |
2006年 | 29565篇 |
2005年 | 28540篇 |
2004年 | 28258篇 |
2003年 | 27193篇 |
2002年 | 26692篇 |
2001年 | 46280篇 |
2000年 | 46374篇 |
1999年 | 37269篇 |
1998年 | 13612篇 |
1997年 | 13824篇 |
1996年 | 13081篇 |
1995年 | 12179篇 |
1994年 | 11813篇 |
1993年 | 11891篇 |
1992年 | 30541篇 |
1991年 | 29944篇 |
1990年 | 29224篇 |
1989年 | 28552篇 |
1988年 | 26397篇 |
1987年 | 25241篇 |
1986年 | 23740篇 |
1985年 | 23821篇 |
1984年 | 19584篇 |
1983年 | 17084篇 |
1982年 | 13140篇 |
1981年 | 12060篇 |
1980年 | 11120篇 |
1979年 | 18702篇 |
1978年 | 14922篇 |
1977年 | 13558篇 |
1976年 | 12961篇 |
1975年 | 14485篇 |
1974年 | 15679篇 |
1973年 | 15524篇 |
1972年 | 14251篇 |
1971年 | 12845篇 |
1970年 | 11197篇 |
1969年 | 11054篇 |
1968年 | 9835篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
941.
A selective system toxic towards mammalian cells expressing the liver-specific isozyme of alcohol dehydrogenase (L-ADH) has been developed. A number of alpha-unsaturated primary and secondary alcohols were assayed for their ability to serve as substrates for rat liver ADH and were screened for cytotoxicity towards L-ADH+ and L-ADH- cells. 1-Propen-3-ol and 1-penten-3-ol were identified as agents showing selective cytotoxicity. Reconstruction experiments demonstrated that 1-propen-3-ol at a concentration of 15 microM could be used to recover L-ADH- clones from mixed populations of L-ADH+ and L-ADH cells. Cells expressing the non-allelic S-ADH isozyme were not killed under these conditions. The selective system defined in this report is thus isozyme-specific. 相似文献
942.
943.
944.
945.
946.
947.
A Sólyom S Tóth I Holczinger J Vajda Z Tóth R Kálmánchey 《Applied neurophysiology》1985,48(1-6):222-225
Four thalamic and cortical recordings were carried out in 5 patients. The thalamic-evoked potentials were typical and revealed a triphasic complex, but their latencies showed a relatively high standard deviation. They could be divided into two groups according to their latencies, both of which had low SD. These data suggested that there could be two types of latency of thalamic SEP, because the 4 patients' body sizes were very similar. More detailed surface, cortical and depth recordings are needed to resolve these questions. 相似文献
948.
J H Brock 《BMJ (Clinical research ed.)》1986,293(6546):518-520
949.
950.
Isolation of serum chylomicrons prior to density gradient ultracentrifugation of other serum lipoprotein classes 总被引:1,自引:0,他引:1
A H Terpstra 《Analytical biochemistry》1985,150(1):221-227
A method for the removal of serum chylomicrons before density gradient ultracentrifugation of the other serum lipoproteins using an SW 41 swinging bucket rotor is presented. In a preliminary spin, the chylomicrons with an Sf greater than 400 X 10(-13) s float to the top of the gradient, whereas the other lipoproteins are retained in the infranatant fraction. After removal of the chylomicrons, the other serum lipoproteins are subsequently fractionated by isopycnic density gradient ultracentrifugation. Analysis of the separated lipoprotein fractions suggested that this procedure permits isolation of a chylomicron fraction consisting solely of chylomicrons but that the very low density lipoprotein fraction subsequently isolated also contains chylomicrons or chylomicron remnants with an Sf less than 400 X 10(-13) s, and that there is considerable overlap in flotation rate and particle size of very low density lipoproteins and chylomicrons. 相似文献