全文获取类型
收费全文 | 334952篇 |
免费 | 22693篇 |
国内免费 | 61篇 |
出版年
2021年 | 2825篇 |
2020年 | 2324篇 |
2019年 | 2648篇 |
2018年 | 5665篇 |
2017年 | 5312篇 |
2016年 | 6952篇 |
2015年 | 8156篇 |
2014年 | 9424篇 |
2013年 | 13160篇 |
2012年 | 15826篇 |
2011年 | 15845篇 |
2010年 | 10718篇 |
2009年 | 8604篇 |
2008年 | 13585篇 |
2007年 | 13904篇 |
2006年 | 13144篇 |
2005年 | 12275篇 |
2004年 | 12077篇 |
2003年 | 11415篇 |
2002年 | 11040篇 |
2001年 | 11362篇 |
2000年 | 10934篇 |
1999年 | 8743篇 |
1998年 | 3014篇 |
1997年 | 2639篇 |
1996年 | 2426篇 |
1995年 | 2285篇 |
1992年 | 6729篇 |
1991年 | 6825篇 |
1990年 | 6664篇 |
1989年 | 6569篇 |
1988年 | 6114篇 |
1987年 | 5644篇 |
1986年 | 5175篇 |
1985年 | 5476篇 |
1984年 | 4444篇 |
1983年 | 3634篇 |
1982年 | 2526篇 |
1979年 | 3945篇 |
1978年 | 3058篇 |
1977年 | 2814篇 |
1976年 | 2744篇 |
1975年 | 3268篇 |
1974年 | 3587篇 |
1973年 | 3549篇 |
1972年 | 3098篇 |
1971年 | 2956篇 |
1970年 | 2516篇 |
1969年 | 2454篇 |
1968年 | 2301篇 |
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
951.
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
952.
953.
Peter V Scott 《BMJ (Clinical research ed.)》1982,285(6350):1277-1278
954.
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
955.
956.
K. V. Minin 《Paleontological Journal》2012,46(8):927-935
A study of the morphological variability of seven species of sea urchins of the genus Echinus from the Northeast Atlantic and Arctic with different depth preferences showed that in the group of species E. tenuispinus, E. esculentus, E. melo, E. acutus, E. elegans, E. affinis, and E. alexandri, arranged based on increasing depth of occurrence, the maximum test diameter decreases, the diameter of the apical system increases, the ratio of the number of interambulacral plates to the number of ambulacral plates increases, buccal and periproctal spines tend to disappear, and the number of ambulacral plates lacking a primary tubercle sharply decreases. At the same time, the test height decreases, while the number of secondary tubercles on coronal plates and number of lateral teeth on the valves of the globiferous pedicellariae increases. The change in the first six characters reflects the process of retention of juvenile features in deep-water Echinus. Similar trends in test height, apical system diameter and the ratio of the number of interambulacral plates to the number of ambulacral plates are recorded while comparing shallow-water and deep-sea populations of the eurybathic species E. acutus. This suggests that this species may currently be in the process of speciation. 相似文献
957.
958.
959.
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
960.