全文获取类型
收费全文 | 402篇 |
免费 | 17篇 |
专业分类
419篇 |
出版年
2023年 | 1篇 |
2022年 | 7篇 |
2021年 | 12篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 7篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 20篇 |
2014年 | 15篇 |
2013年 | 40篇 |
2012年 | 35篇 |
2011年 | 37篇 |
2010年 | 25篇 |
2009年 | 23篇 |
2008年 | 25篇 |
2007年 | 17篇 |
2006年 | 17篇 |
2005年 | 29篇 |
2004年 | 23篇 |
2003年 | 13篇 |
2002年 | 9篇 |
2001年 | 1篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1989年 | 5篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1974年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有419条查询结果,搜索用时 0 毫秒
131.
Self-assembly cloning: a rapid construction method for recombinant molecules from multiple fragments
Enzyme-free cloning (EFC) can rapidly produce an in-frame fusion gene with multiple fragments. To practically apply EFC, we investigated the extent and sequence of complementary staggered overhangs necessary to direct self-assembly of multiple fragments as well as a size limitation of the constructed DNA molecule. Six-base pair overhangs with 50% GC content were sufficient to direct self-assembly. A functional plasmid that exceeded 10 kb, which includes an in-frame fusion domain, was efficiently constructed from four PCR fragments in one step by our improved method. 相似文献
132.
Kanno Y Ishisaki A Kawashita E Chosa N Nakajima K Nishihara T Toyoshima K Okada K Ueshima S Matsushita K Matsuo O Matsuno H 《The Journal of biological chemistry》2011,286(11):8952-8960
The contribution of plasminogen (Plg)/plasmin, which have claimed to be the main fibrinolytic regulators in the bone metabolism, remains unclear. This study evaluated how the absence of Plg affects the function of osteoblast (OB) and osteoclast (OC). There was a larger population of pre-OCs in bone marrow-derived cells from the Plg(-/-) mice than the population of that from the WT mice. In addition, the absence of Plg suppressed the expression of osteoprotegerin in OBs. Moreover, an exogenous plasmin clearly induced the osteoprotegerin expression in Plg(-/-) OBs. The osteoclastogenesis of RAW264.7 mouse monocyte/macrophage lineage cells in co-culture with OBs from the Plg(-/-) mice was significantly accelerated in comparison with that in co-culture with OBs from the WT mice. Intriguingly, the accelerated OC differentiation of RAW264.7 cells co-cultured with Plg(-/-) OBs was clearly suppressed by the treatment of an exogenous plasmin. Consequently, Plg(-/-) mice display decreased bone mineral density. These findings could eventually lead to the development of new clinical therapies for bone disease caused by a disorder of the fibrinolytic system. 相似文献
133.
134.
135.
Kawao N Okada K Kawata S Okamoto C Tsuritani M Ueshima S Matsuo O 《Biochimica et biophysica acta》2007,1773(6):718-727
Since the signal transduction mechanisms responsible for liver regeneration mediated by the plasminogen/plasmin system remain largely undetermined, we have investigated whether plasmin regulates the pro-apoptotic protein Bim(EL) in primary hepatocytes. Plasmin bound to hepatocytes in part via its lysine binding sites (LBS). Plasmin also triggered phosphorylation of ERK1/2 without cell detachment. The plasmin-induced phosphorylation of ERK1/2 was inhibited by the LBS inhibitor epsilon-aminocaproic acid (EACA), the serine protease inhibitor aprotinin, and the MEK inhibitor PD98059. DFP-inactivated plasmin failed to phosphorylate ERK1/2. Plasmin temporally decreased the starvation-induced expression of Bim(EL) and activation of caspase-3 via the ERK1/2 signaling pathway, resulting in an enhancement of cell survival. The amount of mRNA for Bim increased 1 day after the injection of CCl(4) in livers of plasminogen knockout (Plg-KO) and the wild-type (WT) mice. The increase in Bim(EL) protein persisted for at least 7 days post-injection in livers of Plg-KO mice, whereas WT mice showed an increase in Bim(EL) protein 1 day after the injection. Plg-KO and WT mice showed notable phosphorylation of ERK1/2 7 and 3 days after the injection of CCl(4), respectively. Our data suggest that the plasminogen/plasmin system could decrease Bim(EL) expression via the ERK1/2 signaling pathway during liver regeneration. 相似文献
136.
Mesenchymal progenitor cells in adult human dental pulp and their ability to form bone when transplanted into immunocompromised mice 总被引:3,自引:0,他引:3
Otaki S Ueshima S Shiraishi K Sugiyama K Hamada S Yorimoto M Matsuo O 《Cell biology international》2007,31(10):1191-1197
The technique of tissue engineering is developing for the restoration of lost tissues. This new technique requires cells that fabricate tissue. Mesenchymal stem cells in bone marrow have been used as the cell source for this technique; however, dental pulp cells have recently been shown to possess stem-cell-like properties. We earlier demonstrated that dental pulp cells proliferate and produce an extracellular matrix that subsequently becomes mineralized in vitro. We now report that such dental pulp cells (first to eighth passage) produced bone instead of dentin when those cells were implanted into subcutaneous sites in immunocompromised mice with HA/TCP powder as their carrier. This evidence shows that dental pulp cells are the common progenitors of odontoblasts and osteoblasts, or dental pulp cells are mesenchymal stem cells themselves. It is expected that dental pulp cells can be a useful candidate cell source for tissue engineering, and contain the potential of new therapeutic approaches for the restoration of damaged or diseased tissue. 相似文献
137.
138.
Ngoc‐Ha Thi Tran Taichi Oguchi Nobuhumi Akatsuka Etsuko Matsunaga Akiyoshi Kawaoka Akiyo Yamada Yoshihiro Ozeki Kazuo N. Watanabe Akira Kikuchi 《Plant biotechnology journal》2019,17(4):801-811
The breeding of plantation forestry trees for the possible afforestation of marginal land would be one approach to addressing global warming issues. Here, we developed novel transgenic Eucalyptus trees (Eucalyptus camaldulensis Dehnh.) harbouring an RNA‐Binding‐Protein (McRBP) gene derived from a halophyte plant, common ice plant (Mesembryanthemum crystallinum L.). We conducted screened‐house trials of the transgenic Eucalyptus using two different stringency salinity stress conditions to evaluate the plants’ acute and chronic salt stress tolerances. Treatment with 400 mM NaCl, as the high‐stringency salinity stress, resulted in soil electrical conductivity (EC) levels >20 mS/cm within 4 weeks. With the 400 mM NaCl treatment, >70% of the transgenic plants were intact, whereas >40% of the non‐transgenic plants were withered. Treatment with 70 mM NaCl, as the moderate‐stringency salinity stress, resulted in soil EC levels of approx. 9 mS/cm after 2 months, and these salinity levels were maintained for the next 4 months. All plants regardless of transgenic or non‐transgenic status survived the 70 mM NaCl treatment, but after 6‐month treatment the transgenic plants showed significantly higher growth and quantum yield of photosynthesis levels compared to the non‐transgenic plants. In addition, the salt accumulation in the leaves of the transgenic plants was 30% lower than that of non‐transgenic plants after 15‐week moderate salt stress treatment. There results suggest that McRBP expression in the transgenic Eucalyptus enhances their salt tolerance both acutely and chronically. 相似文献
139.
140.
Maintenance of self-renewal and pluripotency in mouse embryonic stem cells (mESCs) is regulated by the balance between several extrinsic signaling pathways. Recently, we demonstrated that heparan sulfate (HS) chains play important roles in the maintenance and differentiation of mESCs by regulating extrinsic signaling. Sulfated HS structures are modified by various sulfotransferases during development. However, the significance of specific HS structures during development remains unclear. Here, we show that 3-O-sulfated HS structures synthesized by HS 3-O-sulfotransferases (3OSTs) and recognized by the antibody HS4C3 increase during differentiation of mESCs. Furthermore, expression of Fas on the cell surface of the differentiated cells also increased. Overexpression of the HS4C3-binding epitope in mESCs induced apoptosis and spontaneous differentiation even in the presence of LIF and serum. These data showed that the HS4C3-binding epitope was required for differentiation of mESCs. Up-regulation of the HS4C3-binding epitope resulted in the recruitment of Fas from the cytoplasm to lipid rafts on the cell surface followed by activation of Fas signaling. Indeed, the HS4C3-binding epitope interacted with a region that included the heparin-binding domain (KLRRRVH) of Fas. Reduced self-renewal capability in cells overexpressing 3OST resulted from the degradation of Nanog by activated caspase-3, which is downstream of Fas signaling, and was rescued by the inhibition of Fas signaling. We also found that knockdown of 3OST and inhibition of Fas signaling reduced the potential for differentiation into the three germ layers during embryoid body formation. This is the first demonstration that activation of Fas signaling is mediated by an increase in the HS4C3-binding epitope and indicates a novel signaling pathway for differentiation in mESCs. 相似文献