全文获取类型
收费全文 | 384篇 |
免费 | 17篇 |
出版年
2022年 | 6篇 |
2021年 | 12篇 |
2019年 | 5篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 16篇 |
2014年 | 14篇 |
2013年 | 26篇 |
2012年 | 23篇 |
2011年 | 24篇 |
2010年 | 9篇 |
2009年 | 5篇 |
2008年 | 16篇 |
2007年 | 13篇 |
2006年 | 12篇 |
2005年 | 12篇 |
2004年 | 15篇 |
2003年 | 5篇 |
2002年 | 8篇 |
2001年 | 16篇 |
2000年 | 4篇 |
1998年 | 3篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1992年 | 7篇 |
1991年 | 10篇 |
1990年 | 9篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 13篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 6篇 |
1970年 | 2篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1966年 | 4篇 |
1960年 | 2篇 |
排序方式: 共有401条查询结果,搜索用时 15 毫秒
81.
We have examined cytokeratin distribution and their nature in toe pads of the Himalayan tree-frog Philautus annandalii. Toe pads are expanded tips of digits and show modifications of their ventral epidermis for adhesion. The toe pad epidermal cells, being organized into 3–4 rows, possess keratin bundles, especially in surface nanostructures that are involved in adhesion. Immunohistochemical localization using a pan-cytokeratin antibody revealed that cytokeratin immunoreactivity is the strongest in the mid- to basal cell rows of the epidermis, which parallels our previous ultrastructural observation of dense keratin bundles present in this part of the epidermis. The remainder of the epidermis (i.e., the superficial cell layer) showed little immunoreactivity. Immunoblot analysis revealed that toe-pads possessed keratins prominently in the molecular mass of 50 kDa. Possible presence of keratin 5 in toe pad epidermis has been correlated with its usual distribution pattern in mammalian epidermis. 相似文献
82.
Grzegorzewski KJ Yao XT Kreider B Olsen HS Morris TS Zhang L Sanyal I Nardelli B Zukauskas D Brewer L Bong GW Kim Y Garotta G Salcedo TW 《Cytokine》2001,13(4):209-219
Myeloid progenitor inhibitory factor (MPIF)-2 is a beta-chemokine with select and potent activities on eosinophils and myeloid progenitors. In the beta-chemokine family, biological activity is modulated by differential processing of the amino-terminus. Here, for MPIF-2, we describe the biological activities of NH(2)-terminal deletion mutants and compare regions necessary for eosinophil and myeloid progenitor activities. Five MPIF-2 proteins with deletions at the amino-terminus were produced in Escherichia coli and assayed for calcium mobilization, chemotaxis and receptor binding activities on eosinophils, and for their ability to inhibit colony formation of human myeloid bone marrow progenitors. For eosinophils, deletion of the first two amino acids did not markedly alter activity, while subsequent truncations result in a complete loss of activity. One of the MPIF-2 mutants, MPIF-2 (P30-R99) was converted from an agonist to an antagonist of eotaxin, MPIF-2 and MCP-4 functional responses in eosinophil calcium flux and chemotaxis assays. Surprisingly, while displaying a complete loss of agonist activity toward eosinophils, MPIF-2 (P30-R99) retains ability to inhibit human bone marrow myeloid progenitor cell colony formation. In addition, processing at the amino terminus of MPIF-2 in vivo, may result in a chemokine with altered biological activities. 相似文献
83.
84.
85.
86.
87.
88.
89.
Acs2p is one of two acetyl-coenzyme A synthetases in Saccharomyces cerevisiae. We have prepared and characterized a monoclonal antibody specific for Acs2p and find that Acs2p is localized primarily to the nucleus, including the nucleolus, with a minor amount in the cytosol. We find that Acs2p is required for replicative longevity: an acs2? strain has a reduced replicative life span compared to wild-type and acs1? strains. Furthermore, replicatively aged acs2? cells contain elevated levels of extrachromosomal rDNA circles, and silencing at the rDNA locus is impaired in an acs2? strain. These findings indicate that Acs2p-mediated synthesis of acetyl-CoA in the nucleus functions to promote rDNA silencing and replicative longevity in yeast. 相似文献
90.
G M Edwards H E Huber D DeFeo-Jones G Vuocolo P J Goodhart R Z Maigetter G Sanyal A Oliff D C Heimbrook 《The Journal of biological chemistry》1992,267(12):7971-7974
The retinoblastoma susceptibility gene (RB) encodes a 928-amino acid protein (pRB) that is hypothesized to function in a pathway that restricts cell proliferation. The immortalizing proteins from three distinct DNA tumor viruses (SV40 large T antigen, adenovirus E1a, and human papilloma virus Type 16 E7) have been shown to interact with RB protein through two noncontiguous regions comprised of amino acids 393-572 (domain A) and 646-772 (domain B). We constructed a truncated form of RB (RB p60) that retains these two domains but eliminates the N-terminal 386 amino acids of RB. RB p60 was expressed in Escherichia coli in inclusion bodies. After solubilization, it was refolded in the presence of magnesium chloride, and the active protein was isolated with an E7 peptide affinity column. The protein that elutes from this column is functionally homogenous in its ability to bind immobilized E7 protein. Thermal denaturation studies provide additional evidence for the conformational homogeneity of the isolated protein. This purification scheme allows the isolation of significant amounts of RB p60 protein that is suitable for structural and functional studies. 相似文献