全文获取类型
收费全文 | 414篇 |
免费 | 24篇 |
专业分类
438篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 7篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 15篇 |
2014年 | 23篇 |
2013年 | 23篇 |
2012年 | 25篇 |
2011年 | 19篇 |
2010年 | 17篇 |
2009年 | 22篇 |
2008年 | 36篇 |
2007年 | 28篇 |
2006年 | 32篇 |
2005年 | 15篇 |
2004年 | 35篇 |
2003年 | 26篇 |
2002年 | 22篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 7篇 |
1998年 | 8篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 1篇 |
1971年 | 2篇 |
排序方式: 共有438条查询结果,搜索用时 0 毫秒
121.
122.
123.
Two six-coordinated manganese(II) complexes [Mn(pydien)Cl](ClO4) · C2H5OH (1), [Mn(pydien)NCS](ClO4) (2) and two seven-coordinated manganese(II) complexes [Mn(pydado)Cl](ClO4) (3), [Mn(pydado)NCS](ClO4) (4) have been obtained using linear penta and hexadentate ligands pydien and pydado (pydien: 1,7-bis(2-pyridylmethyl)-1,4,7-triazaheptane and pydado: 1,10-bis(pyridylmethyl)-1,10-diaza-4,7-dioxadecane). The crystal structures for all compounds have been determined. 1 and 3 crystallize in the triclinic space group , 2 crystallizes in the orthorhombic space group Pbca, whereas 4 crystallizes in the monoclinic space group P21/c. The bound anion (chloro or isothiocyanato) in complexes 1 and 2 has no influence on the geometry of six-coordinate manganese(II) complexes, whereas the geometry and the wrapping of the hexadentate ligand (pydado) around Mn2+ cation depend on the nature of the bound anion. The complex 3 has a capped octahedron geometry with the two pyridyl groups in trans position, while the geometry of complex 4 can be described as pentagonal bipyramid with one pyridyl group and a thiocyanate anion in the axial positions. 相似文献
124.
125.
126.
The present study was designed to investigate the incorporation of zinc (Zn) into cultured UMR-106 osteoblasts in response
to mineralization caused by the addition of β-glycerophosphate. As a result of the induced mineralization, the contents of
calcium (Ca), phosphorus (P), and Zn in the monolayer increased, whereas the magnesium (Mg) content did not change. The activity
of alkaline phosphatase (ALP) also increased during the process.
The zinc distribution in the cell monolayer was studied using Zinquin, a fluorescent zinc ion chelator. The double fluorescent
labeling with Zinquin and calcein revealed that zinc was localized both as intracellular vesicles and extracellular clusters,
whereas calcium was colocalized with extracellular zinc. These results suggest that zinc is involved in the mineralization
process of UMR-106 cells. 相似文献
127.
Y Takubo Y Nishimura E M Zytoon T Nishihara M Kondo 《Microbiology and immunology》1989,33(12):1053-1057
From a predatory bacterium, MC-3, a mutant strain which lost predation ability was isolated by chance selection. Biological properties of the mutant were the same as the parent except only saprophytic property. Properties of the parent and the mutant strains of MC-3, such as bacteriolytic activity of the culture supernatant, digestion of peptidoglycan of the host bacteria, and growth by utilizing the host cells or their cytoplasmic substances, suggested that cell surface structure of the host cell plays an important role in predation and host specificity. 相似文献
128.
Emilie Tourneur Sanae Ben Mkaddem Cécilia Chassin Marcelle Bens Jean-Michel Goujon Nicolas Charles Christophe Pellefigues Meryem Aloulou Alexandre Hertig Renato C. Monteiro Stephen E. Girardin Dana J. Philpott Eric Rondeau Carole Elbim Catherine Werts Alain Vandewalle 《PLoS pathogens》2013,9(1)
Acute pyelonephritis (APN), which is mainly caused by uropathogenic Escherichia coli (UPEC), is the most common bacterial complication in renal transplant recipients receiving immunosuppressive treatment. However, it remains unclear how immunosuppressive drugs, such as the calcineurin inhibitor cyclosporine A (CsA), decrease renal resistance to UPEC. Here, we investigated the effects of CsA in host defense against UPEC in an experimental model of APN. We show that CsA-treated mice exhibit impaired production of the chemoattractant chemokines CXCL2 and CXCL1, decreased intrarenal recruitment of neutrophils, and greater susceptibility to UPEC than vehicle-treated mice. Strikingly, renal expression of Toll-like receptor 4 (Tlr4) and nucleotide-binding oligomerization domain 1 (Nod1), neutrophil migration capacity, and phagocytic killing of E. coli were significantly reduced in CsA-treated mice. CsA inhibited lipopolysaccharide (LPS)-induced, Tlr4-mediated production of CXCL2 by epithelial collecting duct cells. In addition, CsA markedly inhibited Nod1 expression in neutrophils, macrophages, and renal dendritic cells. CsA, acting through inhibition of the nuclear factor of activated T-cells (NFATs), also markedly downregulated Nod1 in neutrophils and macrophages. Silencing the NFATc1 isoform mRNA, similar to CsA, downregulated Nod1 expression in macrophages, and administration of the 11R-VIVIT peptide inhibitor of NFATs to mice also reduced neutrophil bacterial phagocytosis and renal resistance to UPEC. Conversely, synthetic Nod1 stimulating agonists given to CsA-treated mice significantly increased renal resistance to UPEC. Renal transplant recipients receiving CsA exhibited similar decrease in NOD1 expression and neutrophil phagocytosis of E. coli. The findings suggest that such mechanism of NFATc1-dependent inhibition of Nod1-mediated innate immune response together with the decrease in Tlr4-mediated production of chemoattractant chemokines caused by CsA may contribute to sensitizing kidney grafts to APN. 相似文献
129.
To clarify the mechanism of the cardiotoxic action of adriamycin (ADM), the participation of free radicals from ADM in cardiotoxicity was investigated through the protective action of glutathione (GSH) or by using electron spin resonance (ESR). Oxidation of ADM by horseradish peroxidase and H2O2 (HRP-H2O2) was blocked by GSH concentration dependently. Inactivation of creatine kinase (CK) induced during interaction of ADM with HRP-H2O2 was also protected by GSH. Other anthracycline antitumor drugs that have a p-hydroquinone structure in the B ring also inactivated CK, and GSH inhibited the inactivation of CK. These results suggest that ADM was activated through oxidation of the p-hydroquinone in the B ring by HRP-H2O2. Although ESR signals of the oxidative ADM B ring semiquinone were not detected, glutathionyl radicals were formed during the interaction of ADM with HRP-H2O2 in the presence of GSH. ADM may be oxidized to the ADM B ring semiquinone and then reacts with the SH group. However, ESR signals of ADM C ring semiquinone, which was reductively formed by xanthine oxidase (XO) and hypoxanthine (HX) under anaerobic conditions, were not diminished by GSH, but they completely disappeared with ferric ion. These results indicate that oxidative ADM B ring semiquinones oxidized the SH group in CK, but reductive ADM C ring semiquinone radicals may participate in the oxidation of lipids or DNA and not of the SH group. 相似文献
130.
Sujii Patricia Sanae Tambarussi Evandro Vagner Grando Carolina de Aguiar Silvestre Ellida Viana João Paulo Gomes Brancalion Pedro H. S. Zucchi Maria Imaculada 《Conservation Genetics》2021,22(3):383-396
Conservation Genetics - Gene flow may occur both through pollen movement and seed dispersal, although their relative contribution to overall species gene flow is not understood for most tropical... 相似文献