全文获取类型
收费全文 | 12800篇 |
免费 | 1129篇 |
国内免费 | 4篇 |
专业分类
13933篇 |
出版年
2023年 | 45篇 |
2022年 | 100篇 |
2021年 | 213篇 |
2020年 | 101篇 |
2019年 | 161篇 |
2018年 | 183篇 |
2017年 | 167篇 |
2016年 | 345篇 |
2015年 | 546篇 |
2014年 | 699篇 |
2013年 | 799篇 |
2012年 | 1023篇 |
2011年 | 995篇 |
2010年 | 660篇 |
2009年 | 575篇 |
2008年 | 838篇 |
2007年 | 822篇 |
2006年 | 789篇 |
2005年 | 715篇 |
2004年 | 679篇 |
2003年 | 700篇 |
2002年 | 642篇 |
2001年 | 104篇 |
2000年 | 85篇 |
1999年 | 131篇 |
1998年 | 205篇 |
1997年 | 127篇 |
1996年 | 114篇 |
1995年 | 133篇 |
1994年 | 100篇 |
1993年 | 123篇 |
1992年 | 114篇 |
1991年 | 73篇 |
1990年 | 70篇 |
1989年 | 59篇 |
1988年 | 57篇 |
1987年 | 42篇 |
1986年 | 52篇 |
1985年 | 51篇 |
1984年 | 66篇 |
1983年 | 40篇 |
1982年 | 52篇 |
1981年 | 44篇 |
1980年 | 33篇 |
1979年 | 28篇 |
1978年 | 23篇 |
1977年 | 35篇 |
1976年 | 23篇 |
1974年 | 28篇 |
1973年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Christine Rosenthal 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1957,27(6):280-284
Ohne ZusammenfassungMit 9 Abbildungen 相似文献
993.
994.
995.
996.
Either of the CD45RB and CD45RO isoforms are effective in restoring T cell,but not B cell,development and function in CD45-null mice 总被引:4,自引:0,他引:4
Ogilvy S Louis-Dit-Sully C Cooper J Cassady RL Alexander DR Holmes N 《Journal of immunology (Baltimore, Md. : 1950)》2003,171(4):1792-1800
The protein tyrosine phosphatase CD45 is expressed as a series of isoforms whose tissue and differentiation stage specificity is broadly conserved in evolution. CD45 has been shown to be an important regulator of a variety of functions in many different hemopoietic lineages. We have chosen an in vivo genetic complementation strategy to investigate the differential functions between isoforms. In this study, we report the characterization of transgenic mice which express the isoforms CD45RO or CD45RB as their only CD45 molecules, at a variety of expression levels and in the majority of hemopoietic lineages. Both CD45RO and CD45RB isoforms reconstitute thymocyte development in a CD45-null mouse background when expressed above a threshold level. The resulting mature T cells populate the peripheral lymphoid organs where they are found at normal frequency. Both CD45RO and CD45RB isoforms also permit T cell function in the periphery, although the threshold for normal function here appears to be set higher than in the thymus. In contrast, neither isoform is capable of fully restoring peripheral B cell maturation, even at levels approaching those in heterozygous CD45(+/-) mice in which maturation is normal. In vitro activation of B cells by Ag-receptor stimulation is only minimally complemented by these CD45RO and CD45RB transgenes. Our results suggest that CD45 isoforms play unique roles which differ between the T and B lineages. 相似文献
997.
Frequency of large granular lymphocytes in peripheral blood of healthy persons and breast cancer patients 总被引:1,自引:0,他引:1
The frequency of large granular lymphocytes (LGL) in the peripheral blood of healthy persons (n = 56) and breast cancer patients (31 cases with stage-I and -II disease and 42 cases with stage-III and -IV disease) was studied. The frequency of LGL in peripheral blood was significantly depressed in cancer patients, and particularly in patients with advanced breast cancer. 相似文献
998.
While the number of sequenced genomes continues to grow, experimentally verified functional annotation of whole genomes remains patchy. Structural genomics projects are yielding many protein structures that have unknown function. Nevertheless, subsequent experimental investigation is costly and time-consuming, which makes computational methods for predicting protein function very attractive. There is an increasing number of noteworthy methods for predicting protein function from sequence and structural data alone, many of which are readily available to cell biologists who are aware of the strengths and pitfalls of each available technique. 相似文献
999.
Aagaard A Listwan P Cowieson N Huber T Ravasi T Wells CA Flanagan JU Kellie S Hume DA Kobe B Martin JL 《Structure (London, England : 1993)》2005,13(2):309-317
Latexin, the only known mammalian carboxypeptidase inhibitor, has no detectable sequence similarity with plant and parasite inhibitors, but it is related to a human putative tumor suppressor protein, TIG1. Latexin is expressed in the developing brain, and we find that it plays a role in inflammation, as it is expressed at high levels and is inducible in macrophages in concert with other protease inhibitors and potential protease targets. The crystal structure of mouse latexin, solved at 1.83 A resolution, shows no structural relationship with other carboxypeptidase inhibitors. Furthermore, despite a lack of detectable sequence duplication, the structure incorporates two topologically analogous domains related by pseudo two-fold symmetry. Surprisingly, these domains share a cystatin fold architecture found in proteins that inhibit cysteine proteases, suggesting an evolutionary and possibly functional relationship. The structure of the tumor suppressor protein TIG1 was modeled, revealing its putative membrane binding surface. 相似文献
1000.