全文获取类型
收费全文 | 22419篇 |
免费 | 2835篇 |
国内免费 | 11篇 |
出版年
2021年 | 291篇 |
2019年 | 223篇 |
2018年 | 275篇 |
2017年 | 241篇 |
2016年 | 408篇 |
2015年 | 649篇 |
2014年 | 791篇 |
2013年 | 1047篇 |
2012年 | 1155篇 |
2011年 | 1171篇 |
2010年 | 720篇 |
2009年 | 684篇 |
2008年 | 978篇 |
2007年 | 987篇 |
2006年 | 862篇 |
2005年 | 840篇 |
2004年 | 860篇 |
2003年 | 862篇 |
2002年 | 809篇 |
2001年 | 591篇 |
2000年 | 559篇 |
1999年 | 504篇 |
1998年 | 323篇 |
1997年 | 287篇 |
1996年 | 269篇 |
1995年 | 267篇 |
1994年 | 258篇 |
1993年 | 236篇 |
1992年 | 411篇 |
1991年 | 378篇 |
1990年 | 399篇 |
1989年 | 346篇 |
1988年 | 328篇 |
1987年 | 344篇 |
1986年 | 317篇 |
1985年 | 334篇 |
1984年 | 277篇 |
1983年 | 254篇 |
1982年 | 234篇 |
1981年 | 226篇 |
1980年 | 190篇 |
1979年 | 303篇 |
1978年 | 258篇 |
1977年 | 204篇 |
1976年 | 191篇 |
1975年 | 192篇 |
1974年 | 218篇 |
1973年 | 191篇 |
1972年 | 202篇 |
1969年 | 178篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Regulatory and essential light-chain-binding sites in myosin heavy chain subfragment-1 mapped by site-directed mutagenesis 总被引:2,自引:0,他引:2
E J Mitchell J Karn D M Brown A Newman R Jakes J Kendrick-Jones 《Journal of molecular biology》1989,208(1):199-205
Site-directed mutagenesis of the cloned subfragment-1 (S-1) region of the unc-54 gene, encoding the myosin heavy chain B (MHC B) from Caenorhabditis elegans, has been used to locate binding sites for the regulatory and essential light chains. MHC B S-1 synthesized in Escherichia coli co-migrated with rabbit skeletal muscle myosin S-1 (Mr 90,000), was recognized by anti-nematode myosin antiserum on immunoblots, and specifically bound to 125I-labelled regulatory and essential light chains in a gel overlay assay. Deletion of 102 residues from the C terminus (mutant 655) reduced regulatory and essential light-chain binding to about 30% and 20% of wild-type levels, respectively. Similar reductions in relative binding of the two light chains were seen with mutant 534, in which 38 residues were deleted from the C terminus. Potential binding sites within 75 residues of the C terminus of S-1 were mapped by construction of five other mutant S-1 clones (398, 399, 400, 409 and 411) containing internal deletions of ten to 12 amino acid residues. These showed up to 30% reductions in their ability to bind essential light chains, but did not differ significantly from wild-type in their ability to bind regulatory light chains. Another mutant, 415, containing a deletion of a conserved acidic hexapeptide, E-D-I-R-D-E, showed enhancement of binding of regulatory and essential light chains to 150% and 165% of wild-type levels. Hence, the major binding sites for both light chains are within 38 amino acid residues of the C terminus. 相似文献
62.
63.
64.
65.
66.
S E Hitchcock-DeGregori M D Gerhard W E Brown 《The Journal of biological chemistry》1985,260(5):3228-3231
We have shown that the platelet tropomyosin binding protein described in the accompanying paper (Gerhard, M. D., DiGirolamo, P. M., and Hitchcock-DeGregori, S. E. (1985) J. Biol. Chem. 260, 3221-3227) is identical with human serum albumin. The immunological determinants are completely shared; the tryptic peptide maps are the same; the proteins comigrate on two-dimensional gels; and the amino acid sequences of the first 33 amino acids are the same. Although human serum albumin in plasma or commercially prepared protein will not bind tropomyosin-Affi-Gel 15, it will bind following purification from plasma by chromatography on hydroxylapatite. 相似文献
67.
68.
69.
70.
William Brown 《BMJ (Clinical research ed.)》1920,2(3127):847-851