全文获取类型
收费全文 | 223953篇 |
免费 | 14984篇 |
国内免费 | 49篇 |
专业分类
238986篇 |
出版年
2021年 | 1773篇 |
2018年 | 3125篇 |
2017年 | 3023篇 |
2016年 | 3666篇 |
2015年 | 3201篇 |
2014年 | 4437篇 |
2013年 | 6322篇 |
2012年 | 7542篇 |
2011年 | 8060篇 |
2010年 | 5721篇 |
2009年 | 4876篇 |
2008年 | 7198篇 |
2007年 | 7477篇 |
2006年 | 7178篇 |
2005年 | 6703篇 |
2004年 | 6848篇 |
2003年 | 6567篇 |
2002年 | 6524篇 |
2001年 | 9274篇 |
2000年 | 8953篇 |
1999年 | 6987篇 |
1998年 | 2122篇 |
1997年 | 1953篇 |
1996年 | 1819篇 |
1992年 | 5467篇 |
1991年 | 5677篇 |
1990年 | 5650篇 |
1989年 | 5620篇 |
1988年 | 5212篇 |
1987年 | 4862篇 |
1986年 | 4442篇 |
1985年 | 4677篇 |
1984年 | 3696篇 |
1983年 | 3025篇 |
1982年 | 2013篇 |
1981年 | 1722篇 |
1980年 | 1726篇 |
1979年 | 3338篇 |
1978年 | 2576篇 |
1977年 | 2375篇 |
1976年 | 2330篇 |
1975年 | 2826篇 |
1974年 | 3117篇 |
1973年 | 3084篇 |
1972年 | 2746篇 |
1971年 | 2604篇 |
1970年 | 2212篇 |
1969年 | 2158篇 |
1968年 | 2031篇 |
1967年 | 1797篇 |
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
621.
Identification of the functional site of erythrocyte protein 4.1 involved in spectrin-actin associations 总被引:23,自引:0,他引:23
I Correas T L Leto D W Speicher V T Marchesi 《The Journal of biological chemistry》1986,261(7):3310-3315
Peptides produced by mild chymotryptic digestion of human erythrocyte protein 4.1 mimic the ability of intact 4.1 to promote the binding of spectrin to F-actin. This complex-promoting activity was found to reside in an 8-kDa peptide which was fully functional when dissociated from other protein 4.1-derived peptides, indicating that noncovalent complexes of multiple peptides were not essential for activity. The 8-kDa peptide was incorporated into a ternary complex with spectrin and F-actin in approximately stoichiometric amounts. Amino acid composition and two-dimensional peptide mapping show that the 8-kDa active peptide is located within the 10-kDa region of protein 4.1 which contains a cAMP-dependent phosphorylated site. 相似文献
622.
623.
Peter V Scott 《BMJ (Clinical research ed.)》1982,285(6350):1277-1278
624.
E S Revazova Iu N Solov'ev T M Khizhniakova T V Iudicheva 《Biulleten' eksperimental'no? biologii i meditsiny》1985,99(4):469-471
The authors describe human cancer strains established from 6 cell lines transplanted to nude mice and rats: cancer of the liver, colon, lung, bladder and Burkitt's lymphoma. In spite of a long history (for several years) of cell line transfers in vitro, on transplantation of tumor cells, nude animals established tumors histologically identical to the primary cancer. 相似文献
625.
626.
Zh T A?tbaeva P N Deriabin B V Karal'nik K G Kaverina 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1989,(5):16-20
Highly sensitive and specific erythrocyte diagnostic agents (ED) for the determination of antibodies to Proteus O-antigens have been obtained by the sensitization of formolated sheep red blood cells (SPBC) with activated lipopolysaccharides (LPS) without the use of mediators. The tannin treatment of formolated SRBC and/or the increase of temperature from 45 degrees C to 100 degrees C in the process of the preparation of ED have been found to produce no increase in effectiveness. Antibody ED permitting the detection of Proteus O- and H-antigens has been obtained by the sensitization of formolated chick red blood cells with immunoglobulin preparations to Proteus hydroxylamine antigens, carried out with the use of amidol. The experiments have shown the possibility of using this antibody ED for the determination of O-antibodies in the antigen neutralization test with nonactivated LPS used as an agglutinating agent. The passive hemagglutination test with antibody ED has proved to be a more sensitive method for the detection of O-antibodies than the antigen neutralization test with antigenic ED. The determination of Proteus etiology in the passive hemagglutination test with the use of antigenic ED has been shown to be highly effective in the examination of patients with chronic osteomyelitis at the stage of exacerbation. 相似文献
627.
S V Revenko V V Ermishkin L Ia Selektor 《Biulleten' eksperimental'no? biologii i meditsiny》1989,107(4):395-396
Direct electric current of 3 microA applied through platinum electrode during 10 s to a fine strand teased mechanically from saphenous nerve, inhibits selectively C-fibre spikes in the strand and does not inhibit A-fiber spikes. The selective inhibition of C-fibers spikes in a fine strand is proposed as a method to identify a type of a single nerve fiber. 相似文献
628.
Multiple aligned sequence editor (MASE) 总被引:24,自引:0,他引:24
629.
Phenylalanine hydroxylase (PH) activity was discovered in the liver of 7-12 week old human embryos. Embryonic and adult PHs were identical, as shown by immunoelectrophoresis. Unlike the adult liver PH, the PH content of the extract of cytoplasmic proteins of embryonic liver was reduced but the specific activity was increased more than by one order of magnitude. H (57,000 D) and L (55,000 D) subunits were detected by immunoblotting. The L subunit predominates in the extract of membrane proteins of embryonic liver. Hence, the major part of phenylalanine oxidizing activity in the embryonic liver is related to the enzyme immunochemically identical with the PH of adult liver but differing from it in some structural and functional properties. 相似文献
630.
Immunoperoxidase labeling of fibronectin in one-day-old mouse first lower molars allowed to visualize a striking redistribution of this glycoprotein during terminal cytodifferentiation of odontoblasts. The modifications involved both extracellular and cell surface localizations. The possible roles of these modifications in terminal differentiation of odontoblasts are discussed. 相似文献