全文获取类型
收费全文 | 17423篇 |
免费 | 1592篇 |
国内免费 | 4篇 |
专业分类
19019篇 |
出版年
2022年 | 113篇 |
2021年 | 258篇 |
2020年 | 168篇 |
2019年 | 224篇 |
2018年 | 244篇 |
2017年 | 239篇 |
2016年 | 411篇 |
2015年 | 608篇 |
2014年 | 750篇 |
2013年 | 921篇 |
2012年 | 1079篇 |
2011年 | 1118篇 |
2010年 | 693篇 |
2009年 | 678篇 |
2008年 | 907篇 |
2007年 | 898篇 |
2006年 | 856篇 |
2005年 | 808篇 |
2004年 | 783篇 |
2003年 | 749篇 |
2002年 | 734篇 |
2001年 | 305篇 |
2000年 | 243篇 |
1999年 | 266篇 |
1998年 | 198篇 |
1997年 | 172篇 |
1996年 | 172篇 |
1995年 | 178篇 |
1994年 | 148篇 |
1993年 | 183篇 |
1992年 | 222篇 |
1991年 | 196篇 |
1990年 | 186篇 |
1989年 | 178篇 |
1988年 | 160篇 |
1987年 | 152篇 |
1986年 | 143篇 |
1985年 | 156篇 |
1984年 | 173篇 |
1983年 | 144篇 |
1982年 | 155篇 |
1981年 | 160篇 |
1980年 | 119篇 |
1979年 | 115篇 |
1978年 | 111篇 |
1977年 | 103篇 |
1975年 | 93篇 |
1974年 | 130篇 |
1973年 | 101篇 |
1972年 | 96篇 |
排序方式: 共有10000条查询结果,搜索用时 21 毫秒
71.
Ian Gregg 《BMJ (Clinical research ed.)》1964,1(5375):115-116
72.
73.
74.
75.
Ian Carr 《Cell and tissue research》1967,80(1):140-144
Summary Membranous whorls have been seen in the nuclei of peritoneal and testicular cells which had been subjected to various experimental manoeuvres. It seems likely that this is an early manifestation of cell degeneration which is demonstrated readily only by glutaraldehyde fixation, and to that extent can be regarded as a glutaraldehyde artifact.
Acknowledgements. This work was supported by grants from the Medical Research Council, and the University of Sheffield Tuberculosis Research Fund, and by a grant to the Department from Unilever Ltd.I am grateful to Professor R. Barer for his advice and criticism, to Dr. G. A. Meek for guidance on electron microscopy, to Dr. E. J. Clegg for permission to use material from joint experiments. Technical and photographic assistance was provided by Messrs. P. GarLick and L. Murgatroyd and by Miss M. Tune. 相似文献
76.
Growth and Invasiveness of Candida albicans in the Germ-Free and Conventional Mouse After Oral Challenge 总被引:15,自引:1,他引:14 下载免费PDF全文
Candida albicans was established in large numbers throughout the gut after one oral challenge in the germ-free and in the conventional mouse. Of the strains tested, only the germ-free ND 1 mouse appeared to be susceptible to infection, and this was confined to the stomach mucosa; lesions contained large numbers of hyphal and mycelial forms with blastospores. These forms were also seen in the gut of resistant germ-free ND 4 mice after challenge. Only budding yeast forms were seen in the gut contents from conventional animals. The concentration of sulfhydryl-containing compounds was decreased in the stomach contents from germ-free mice. The stomach tissue of conventional animals seemed to be more acidic than that of germ-free animals, and association of C. albicans with conventional mice neutralized some of this acidity. E(h) values of contents from the gut of unchallenged mice were usually higher in conventional than in germ-free animals; after challenge, the E(h) in both groups decreased. Some reciprocal effects of intestinal microorganisms and host are discussed in relation to intestinal candidiasis. 相似文献
77.
A. J. Phillips 《CMAJ》1965,92(8):391-393
A five-year study was undertaken to determine the incidence of primary bone cancer in Canada in order to assess the effects of subsequent increases in background radiation, should such occur. Eight hundred and twenty-seven cases were investigated, and the annual incidence rate was estimated to be 6.3 per million population. Osteosarcoma was the most common type of tumour, accounting for more than half of all confirmed cases. Over 60% of the tumours occurred in males. 相似文献
78.
79.
80.