全文获取类型
收费全文 | 2314篇 |
免费 | 204篇 |
国内免费 | 5篇 |
出版年
2022年 | 28篇 |
2021年 | 44篇 |
2020年 | 16篇 |
2019年 | 16篇 |
2018年 | 50篇 |
2017年 | 25篇 |
2016年 | 43篇 |
2015年 | 100篇 |
2014年 | 95篇 |
2013年 | 135篇 |
2012年 | 151篇 |
2011年 | 147篇 |
2010年 | 93篇 |
2009年 | 100篇 |
2008年 | 125篇 |
2007年 | 118篇 |
2006年 | 105篇 |
2005年 | 111篇 |
2004年 | 112篇 |
2003年 | 116篇 |
2002年 | 96篇 |
2001年 | 32篇 |
2000年 | 21篇 |
1999年 | 34篇 |
1998年 | 30篇 |
1997年 | 18篇 |
1995年 | 17篇 |
1994年 | 14篇 |
1993年 | 21篇 |
1992年 | 21篇 |
1991年 | 33篇 |
1990年 | 20篇 |
1989年 | 19篇 |
1988年 | 17篇 |
1987年 | 14篇 |
1986年 | 14篇 |
1985年 | 18篇 |
1984年 | 17篇 |
1983年 | 15篇 |
1982年 | 22篇 |
1981年 | 17篇 |
1980年 | 17篇 |
1979年 | 16篇 |
1978年 | 21篇 |
1977年 | 20篇 |
1976年 | 12篇 |
1975年 | 12篇 |
1973年 | 15篇 |
1971年 | 15篇 |
1968年 | 12篇 |
排序方式: 共有2523条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Ultrastructural demonstration of NAD-pyrophosphorylase activity (E.C.2.7.7.1) in isolated mouse liver nuclei was investigated with the use of an electronhistochemical procedure based on the precipitation of pyrophosphate ions with lead ions under conditions permitting simultaneous ATPase inhibition by formaldehyde/ethanol prefixation. In isolated mouse liver nuclei activity of NAD-pyrophosphorylase was found in nucleoli, in interchromatin granules, coiled bodies and strand-like structures in nucleoplasm. 相似文献
5.
6.
Sheila Polakoff 《BMJ (Clinical research ed.)》1987,294(6578):1031-1032
7.
Isolation and expression of an anther-specific gene from tomato 总被引:31,自引:0,他引:31
David Twell Rod Wing Judy Yamaguchi Sheila McCormick 《Molecular & general genetics : MGG》1989,217(2-3):240-245
8.
Glycosylation of methyl (allyl 7,8-O-carbonyl-3-deoxy-alpha-D-manno-2-octulo-pyranosid)o nate with an alpha-(2----4) linked per-O-acetylated KDO-disaccharide bromide derivative under Helferich conditions afforded a 2:1 mixture of the alpha- and beta-linked trisaccharide derivatives in 50% yield. Removal of the protecting groups gave sodium O-[sodium (3-deoxy-alpha-D-manno-2-octulopyranosyl)onate]-(2----4)-O-[ sodium (3-deoxy-alpha- and -beta-D-manno-2-octulopyranosyl)onate]-(2----4)-sodium (allyl 3-deoxy-alpha-D-manno-2-octulopyranosid)onate. Radical copolymerization of the allyl glycosides afforded artificial antigens, suitable for defining antibody specificities directed against the KDO-region of enterobacterial lipopolysaccharides. 相似文献
9.
Robert M. Levin Penelope A. Longhurst Sheila S. Levin Niels Haugaard Alan J. Wein 《Molecular and cellular biochemistry》1990,97(2):153-159
The urinary bladder depends on intracellular ATP for the support of a number of essential intracellular processes including contraction. The concentration of ATP is maintained constant primarily via the rapid transfer of a phosphate from creatine phosphate (CP) to ADP catalyzed by the enzyme creatine kinase (CK). Since muscular pathologies associated with diabetes are in part related to intracellular alterations in metabolism, we have characterized the CK activity in both skeletal muscle and urinary bladder from control and streptozotocin-diabetic rats.The following is a summary of the results: 1) Bladder tissue from control rats showed linear kinetics with a Vmax = 390 nmoles/mg protein/min, and a Km = 275 µM. 2) Urinary bladder tissue isolated from diabetic rats displayed biphasic kinetics with Vmax = 65 and 324 nmoles/mg protein/min, and Km's = 10 µM and 190 µM respectively. 3) Skeletal muscle isolated from control rats showed linear kinetics with an approximate Vmax of 800 nmoles/mg protein/min and a Km of 280 µM CP. 4) Homogenates of skeletal muscle from diabetic rats showed complex kinetics not separable into distict component forms. 5) The Km for ADP for both skeletal muscle and bladder was approximately 10 µM.These studies demonstrate that whereas bladders isolated from both control and diabetic rats possess a low-affinity isomer(s) of CK with similar maximum enzymatic activity, there is a high affinity isomer present within the urinary bladder muscle of diabetic rats that is not present in bladder tissue isolated from control rats. Skeletal muscle isolated from both diabetic and control rats exhibited a maximal activity 2 to 3 times higher than that of the bladder. 相似文献
10.
Mapping of the bcl-2 oncogene on mouse chromosome 1 总被引:1,自引:0,他引:1
B A Mock D Givol L A D'Hoostelaere K Huppi M F Seldin N Gurfinkel T Unger M Potter J F Mushinski 《Cytogenetics and cell genetics》1988,47(1-2):11-15
Two bcl-2 alleles have been identified in inbred strains of mice by restriction fragment length polymorphism (RFLP). Analysis of a bcl-2 RFLP in a series of bilineal congenic strains (C.D2), developed as a tool for chromosomal mapping studies, revealed linkage of bcl-2 to the Idh-1/Pep-3 region of murine chromosome 1. The co-segregation of bcl-2 alleles with allelic forms of two other chromosome 1 loci, Ren-1,2 and Spna-1, in a set of back-cross progeny, positions bcl-2 7.8 cM centromeric from Ren-1,2. 相似文献