全文获取类型
收费全文 | 90292篇 |
免费 | 7643篇 |
国内免费 | 55篇 |
出版年
2023年 | 375篇 |
2022年 | 888篇 |
2021年 | 1638篇 |
2020年 | 1120篇 |
2019年 | 1299篇 |
2018年 | 1787篇 |
2017年 | 1517篇 |
2016年 | 2543篇 |
2015年 | 3863篇 |
2014年 | 3968篇 |
2013年 | 4905篇 |
2012年 | 6186篇 |
2011年 | 5977篇 |
2010年 | 3698篇 |
2009年 | 3533篇 |
2008年 | 4596篇 |
2007年 | 4658篇 |
2006年 | 4291篇 |
2005年 | 4443篇 |
2004年 | 4403篇 |
2003年 | 3871篇 |
2002年 | 3429篇 |
2001年 | 1875篇 |
2000年 | 1676篇 |
1999年 | 1664篇 |
1998年 | 1031篇 |
1997年 | 885篇 |
1996年 | 903篇 |
1995年 | 736篇 |
1994年 | 710篇 |
1993年 | 701篇 |
1992年 | 1172篇 |
1991年 | 1017篇 |
1990年 | 936篇 |
1989年 | 953篇 |
1988年 | 907篇 |
1987年 | 822篇 |
1986年 | 760篇 |
1985年 | 772篇 |
1984年 | 758篇 |
1983年 | 565篇 |
1982年 | 474篇 |
1981年 | 455篇 |
1980年 | 418篇 |
1979年 | 503篇 |
1978年 | 443篇 |
1977年 | 374篇 |
1975年 | 334篇 |
1974年 | 341篇 |
1973年 | 344篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Highly purified feather keratin mRNA, prepared by dissociation of mRNP particles in Na dodecyl sulphate, was translated in a wheat embryo cell-free system with similar efficiency to rabbit globin mRNA and RNA purified from cucumber mosaic virus. The only detectable products of translation of the keratin mRNA were keratin chains, which were identical to native keratin chains as judged by several different criteria. These results support previous conclusions that the keratin mRNA can be obtained in a pure state. 相似文献
993.
Lusinete Aciole de Queiroz 《Mycopathologia》1974,54(4):559-564
A new species of the genusEndomycopsis is proposed. It was isolated from wast water, at Montevideo-Uruguay.By its morphological and biochemical proprieties it differs from allEndomycopsis previously described.Este trabajo fue desarrollado en el Laboratorio de Micologia de la Facultad de Quimica de Montevideo, Uruguay y en uso de una beca de la Universidad Federal de Pernambuco para perfeccio bamiento en el estudo de las levaduras. 相似文献
994.
Does New Guinea cannibalism have nutritional value? 总被引:1,自引:0,他引:1
This paper examines the question of the nutritional value of cannibalism. Although other authors have concluded that the practice does not have such value, we argue that this cannot properly be determined except in the context of the total subsistence economy and local human ecology. The paper also presents a format for the empirical investigation of foodgetting and new ethnographic information about New Guinea cannibalism. Our major conclusion is that this practice does have nutritional value for certain human groups, specifically tropical peoples living at lowmedium population densities and exploiting a diverse range of animal foods. 相似文献
995.
996.
997.
Isobel Braidman Mark Carroll Norman Dance Donald Robinson 《The Biochemical journal》1974,143(2):295-301
Hexosaminidase C was separated from human brain supernatant by immunoadsorption of the A and B forms on to a column of immobilized antibody followed by preparative starch-block electrophoresis. There were some differences in the properties of hexosaminidase C preparations after each of these stages, shown by comparison of their heat-inactivation characteristics and filtration through Bio-Gel P-200. The C form prepared by both separation steps had properties which differed markedly from those of the A and B isoenzymes; its molecular weight was much larger, greater than 200000, it had optimum activity between pH6 and 7 and could not be successfully eluted from DEAE-cellulose, even with high salt concentrations, or from Sephadex G-200. These results seem to support the proposal that the C form is under a separate genetic control from the others. 相似文献
998.
999.
1000.