全文获取类型
收费全文 | 293039篇 |
免费 | 34532篇 |
国内免费 | 152篇 |
专业分类
327723篇 |
出版年
2018年 | 2399篇 |
2016年 | 3086篇 |
2015年 | 4036篇 |
2014年 | 4914篇 |
2013年 | 6733篇 |
2012年 | 7700篇 |
2011年 | 7906篇 |
2010年 | 5199篇 |
2009年 | 5032篇 |
2008年 | 7145篇 |
2007年 | 7319篇 |
2006年 | 7202篇 |
2005年 | 6920篇 |
2004年 | 6782篇 |
2003年 | 6615篇 |
2002年 | 6464篇 |
2001年 | 17258篇 |
2000年 | 17444篇 |
1999年 | 13300篇 |
1998年 | 3862篇 |
1997年 | 4128篇 |
1996年 | 3851篇 |
1995年 | 3489篇 |
1994年 | 3467篇 |
1993年 | 3540篇 |
1992年 | 10388篇 |
1991年 | 10319篇 |
1990年 | 9805篇 |
1989年 | 9636篇 |
1988年 | 8992篇 |
1987年 | 8356篇 |
1986年 | 7556篇 |
1985年 | 7408篇 |
1984年 | 5823篇 |
1983年 | 5074篇 |
1982年 | 3613篇 |
1981年 | 3179篇 |
1980年 | 3030篇 |
1979年 | 5348篇 |
1978年 | 4114篇 |
1977年 | 3749篇 |
1976年 | 3300篇 |
1975年 | 3776篇 |
1974年 | 3947篇 |
1973年 | 3891篇 |
1972年 | 3422篇 |
1971年 | 3183篇 |
1970年 | 2822篇 |
1969年 | 2741篇 |
1968年 | 2412篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Construction of a human cytochrome c gene and its functional expression in Saccharomyces cerevisiae 总被引:1,自引:0,他引:1
Y Tanaka T Ashikari Y Shibano T Amachi H Yoshizumi H Matsubara 《Journal of biochemistry》1988,103(6):954-961
The nucleotide sequences of a partial cDNA and three pseudogenes of human cytochrome c were determined. The complete nucleotide sequences which encode human cytochrome c were constructed on the basis of one of the pseudogenes by in vitro mutagenesis. The constructed human cytochrome c was functionally expressed in Saccharomyces cerevisiae. The recombinant human cytochrome c was purified and characterized. 相似文献
62.
63.
64.
T Smith 《BMJ (Clinical research ed.)》1984,289(6449):909-910
65.
66.
Intraperitoneal stimulation of adoptively sensitized rats with bacterial antigen promotes the localization of lymphoblasts at the site of antigen deposition. Lymphoblast extravasation activity (LEA) is generated only when specifically immune donor lymphocytes and the recipients of these cells share at least on Ag-B haplotype. However, if the specificity criteria for its formation are satisfied, LEA promotes the local development of lymphoblasts of all available specificities and irrespective of their Ag-B genotype. Allogeneic lymphoblasts do not participate actively in the delayed inflammatory reaction even when they are passively recruited into exudates. The results suggest that LEA is a T cell-derived mediator that amplifies the delayed type hypersensitivity reaction by directing recently activated lymphocytes into lesions. 相似文献
67.
68.
69.
70.
G. Rai M. Stamenkovi-Radak T. Savi M. Andjelkovi 《Journal of Zoological Systematics and Evolutionary Research》2008,46(1):31-37
The adaptive significance of inversion polymorphism of Drosophila subobscura is well established. However, little is known about gene combinations within inversions which are coadapted because of population-specific effects. We studied this aspect of Dobzhansky's coadaptation hypothesis, using the systematic inbreeding method. Differences in magnitude and quality of inversion polymorphism in two ecologically and topologically distinct habitats were compared after several generations of continuous full-sib inbreeding. Populations from the two habitats differ in frequency of homokaryotypes after third and fifth generation of inbreeding and in the levels of homozygosity of different gene arrangements. The effect of homozygosity appears population and chromosome specific. 相似文献