全文获取类型
收费全文 | 280篇 |
免费 | 0篇 |
专业分类
教育与普及 | 21篇 |
理论与方法论 | 3篇 |
现状及发展 | 11篇 |
研究方法 | 33篇 |
综合类 | 212篇 |
出版年
2012年 | 10篇 |
2011年 | 20篇 |
2010年 | 2篇 |
2009年 | 1篇 |
2008年 | 13篇 |
2007年 | 16篇 |
2006年 | 14篇 |
2005年 | 18篇 |
2004年 | 15篇 |
2003年 | 20篇 |
2002年 | 13篇 |
2001年 | 13篇 |
2000年 | 22篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1972年 | 1篇 |
1971年 | 7篇 |
1970年 | 12篇 |
1960年 | 2篇 |
1959年 | 4篇 |
1958年 | 9篇 |
1957年 | 6篇 |
1956年 | 6篇 |
1955年 | 4篇 |
1954年 | 4篇 |
1948年 | 12篇 |
排序方式: 共有280条查询结果,搜索用时 0 毫秒
151.
152.
Global analysis of protein expression in yeast 总被引:2,自引:0,他引:2
Ghaemmaghami S Huh WK Bower K Howson RW Belle A Dephoure N O'Shea EK Weissman JS 《Nature》2003,425(6959):737-741
153.
154.
155.
156.
157.
158.
159.
Tellides G Tereb DA Kirkiles-Smith NC Kim RW Wilson JH Schechner JS Lorber MI Pober JS 《Nature》2000,403(6766):207-211
Atherosclerosis and post-transplant graft arteriosclerosis are both characterized by expansion of the arterial intima as a result of the infiltration of mononuclear leukocytes, the proliferation of vascular smooth muscle cells (VSMCs) and the accumulation of extracellular matrix. They are also associated with the presence of the immunomodulatory cytokine interferon-gamma (IFN-gamma). Moreover, in mouse models of atheroma formation or allogeneic transplantation, the serological neutralization or genetic absence of IFN-gamma markedly reduces the extent of intimal expansion. However, other studies have found that exogenous IFN-gamma inhibits cultured VSMC proliferation and matrix synthesis, and reduces intimal expansion in response to mechanical injury. This discrepancy is generally explained by the idea that IFN-gamma either directly activates macrophages, or, by increasing antigen presentation, indirectly activates T cells within the lesions of atherosclerosis and graft arteriosclerosis. These activated leukocytes are thought to express the VSMC-activating cytokines and cell-surface molecules that cause the observed arteriosclerotic responses. Here we have inserted pig and human arteries into the aorta of immunodeficient mice, and we show that IFN-gamma can induce arteriosclerotic changes in the absence of detectable immunocytes by acting on VSMCs to potentiate growth-factor-induced mitogenesis. 相似文献
160.
The lyase activity of the DNA repair protein beta-polymerase protects from DNA-damage-induced cytotoxicity 总被引:11,自引:0,他引:11
Small DNA lesions such as oxidized or alkylated bases are repaired by the base excision repair (BER) pathway. BER includes removal of the damaged base by a lesion-specific DNA glycosylase, strand scission by apurinic/apyrimidinic endonuclease, DNA resynthesis and ligation. BER may be further subdivided into DNA beta-polymerase (beta-pol)-dependent single-nucleotide repair and beta-pol-dependent or -independent long patch repair subpathways. Two important enzymatic steps in mammalian single-nucleotide BER are contributed by beta-pol: DNA resynthesis of the repair patch and lyase removal of 5'-deoxyribose phosphate (dRP). Fibroblasts from beta-pol null mice are hypersensitive to mono-functional DNA-methylating agents, resulting in increases in chromosomal damage, apoptosis and necrotic cell death. Here we show that only the dRP lyase activity of beta-pol is required to reverse methylating agent hypersensitivity in beta-pol null cells. These results indicate that removal of the dRP group is a pivotal step in BER in vivo. Persistence of the dRP moiety in DNA results in the hypersensitivity phenotype of beta-pol null cells and may signal downstream events such as apoptosis and necrotic cell death. 相似文献