全文获取类型
收费全文 | 16350篇 |
免费 | 1462篇 |
国内免费 | 12篇 |
出版年
2022年 | 129篇 |
2021年 | 228篇 |
2020年 | 139篇 |
2019年 | 193篇 |
2018年 | 220篇 |
2017年 | 192篇 |
2016年 | 345篇 |
2015年 | 566篇 |
2014年 | 639篇 |
2013年 | 796篇 |
2012年 | 989篇 |
2011年 | 973篇 |
2010年 | 648篇 |
2009年 | 577篇 |
2008年 | 840篇 |
2007年 | 831篇 |
2006年 | 787篇 |
2005年 | 799篇 |
2004年 | 797篇 |
2003年 | 741篇 |
2002年 | 761篇 |
2001年 | 176篇 |
2000年 | 147篇 |
1999年 | 226篇 |
1998年 | 241篇 |
1997年 | 123篇 |
1996年 | 157篇 |
1995年 | 131篇 |
1994年 | 150篇 |
1993年 | 149篇 |
1992年 | 170篇 |
1991年 | 162篇 |
1990年 | 165篇 |
1989年 | 122篇 |
1988年 | 125篇 |
1987年 | 141篇 |
1986年 | 123篇 |
1985年 | 111篇 |
1984年 | 167篇 |
1983年 | 124篇 |
1982年 | 154篇 |
1981年 | 147篇 |
1980年 | 149篇 |
1979年 | 115篇 |
1978年 | 124篇 |
1977年 | 123篇 |
1976年 | 104篇 |
1975年 | 89篇 |
1974年 | 95篇 |
1973年 | 104篇 |
排序方式: 共有10000条查询结果,搜索用时 593 毫秒
31.
32.
T Henry A Ferguson 《Comparative biochemistry and physiology. B, Comparative biochemistry》1986,85(2):491-496
Informative crosses have verified the genetic basis of a polymorphism at the Ldh-1 locus in brown trout and enzyme activity measurements indicate that the previously described polymorphism at this locus is best explained by a null allele. The LDH-1, LDH-2, LDH-3 and LDH-4 homotetrameric isozymes were purified and subjected to enzyme kinetic analysis. While LDH-1 and LDH-2 displayed catalytic equivalence, important kinetic differences were found between the LDH-3 and LDH-4 isozymes. 相似文献
33.
34.
35.
Henry MacCormac 《BMJ (Clinical research ed.)》1943,2(4325):667-669
36.
37.
38.
Edmund H. Frank Boyce W. Burge Boleslaw H. Liwnicz Linda J. Lotspeich Jocelyn C. White Steven L. Wechsler Frank H. Mayfield Jeffrey T. Keller 《Experimental cell research》1983,146(2):371-376
Cells from cranial and spinal arachnoid membranes of humans were grown in culture. Their growth characteristics, morphology and details of their cytoskeletal composition are described. Arachnoid membranes, obtained at autopsy, were finely minced and incubated in tissue culture medium. Monolayers of cells of homogeneous morphology grew from these tissue fragments. The cells were flat and polygonal. They divided slowly to form non-overlapping monolayers of low cell density. Electron microscopic examination of cultured arachnoid cells revealed numerous desmosome-like tight junctions and abundant intermediate filaments (tonofilaments). Both morphological features are characteristic of arachnoid cells in situ, but not of cells in the fibroblast-rich dura mater. Immunofluorescence microscopy with monoclonal antibodies demonstrated cytokeratin in the cytoplasm of primary cultures of arachnoid cells. Thus we demonstrated that these cultured cells retained certain of the specific differentiated properties of arachnoid cells in situ and that they are not fibroblasts (which lack tight junctions and cytokeratins). To our knowledge, there have been no previous reports of in vitro growth of arachnoid cells. This in vitro model should be useful in studying the response of arachnoid cells to a variety of substances thought to be involved in the chronic inflammatory condition of the meninges known as arachnoiditis. 相似文献
39.
40.
Henry Souttar 《BMJ (Clinical research ed.)》1951,2(4746):1503-1504