首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   481篇
  免费   38篇
  2021年   7篇
  2018年   10篇
  2017年   4篇
  2016年   10篇
  2015年   14篇
  2014年   8篇
  2013年   14篇
  2012年   17篇
  2011年   14篇
  2010年   18篇
  2009年   16篇
  2008年   17篇
  2007年   22篇
  2006年   14篇
  2005年   20篇
  2004年   18篇
  2003年   15篇
  2002年   18篇
  2001年   20篇
  2000年   11篇
  1999年   16篇
  1998年   17篇
  1997年   6篇
  1996年   8篇
  1995年   7篇
  1994年   4篇
  1993年   5篇
  1992年   7篇
  1991年   11篇
  1990年   9篇
  1989年   4篇
  1988年   6篇
  1987年   9篇
  1986年   9篇
  1985年   9篇
  1984年   7篇
  1983年   4篇
  1982年   4篇
  1979年   5篇
  1978年   3篇
  1977年   6篇
  1975年   4篇
  1974年   3篇
  1973年   3篇
  1972年   3篇
  1878年   4篇
  1875年   2篇
  1874年   2篇
  1857年   3篇
  1854年   2篇
排序方式: 共有519条查询结果,搜索用时 15 毫秒
511.
A-kinase anchoring proteins (AKAPs) include a family of scaffolding proteins that target protein kinase A (PKA) and other signaling proteins to cellular compartments and thereby confine the activities of the associated proteins to distinct regions within cells. AKAPs bind PKA directly. The interaction is mediated by the dimerization and docking domain of regulatory subunits of PKA and the PKA-binding domain of AKAPs. Analysis of the interactions between the dimerization and docking domain and various PKA-binding domains yielded a generalized motif allowing the identification of AKAPs. Our bioinformatics and peptide array screening approaches based on this signature motif identified GSKIP (glycogen synthase kinase 3β interaction protein) as an AKAP. GSKIP directly interacts with PKA and GSK3β (glycogen synthase kinase 3β). It is widely expressed and facilitates phosphorylation and thus inactivation of GSK3β by PKA. GSKIP contains the evolutionarily conserved domain of unknown function 727. We show here that this domain of GSKIP and its vertebrate orthologues binds both PKA and GSK3β and thereby provides a mechanism for the integration of PKA and GSK3β signaling pathways.  相似文献   
512.
The adult greater Kudu antelope has two hemoglobin components, Hb A and Hb B, with one alpha and two beta chains. The complete amino-acid sequences of these three chains are presented. The two beta chains differ only in one residue at position 16 (Gly----Ser) and may be the product of two allelic genes. The primary structure of the chains was determined by sequencing the tryptic peptides after their isolation from the tryptic digest of the chains by high performance liquid chromatography. The alignment of these peptides was deduced from homology with the chains of bovine hemoglobin. Between the Kudu hemoglobins and those of cattle a high degree of homology was found.  相似文献   
513.
514.
The structures and spectroscopic properties of various conformations of two diasteromeric pairs of enantiomers of pentacoordinate CuII bispidine complexes with chiral tetradentate ligands are reported. With one of the ligands an interesting type of distortional isomerism was observed experimentally, and this was studied in detail on the basis of the experimental structural and spectroscopic data (UV-Vis-NIR, EPR) and a DFT-, MM- and ligand-field-theory-based analysis.  相似文献   
515.
Incubation of isolated rat liver mitochondria with the pure rabbit reticulocyte lipoxygenase caused a time-dependent inactivation of the monoamine oxidase activities A and B. Furthermore, a conversion of the monoamine oxidase into a diamine oxidase was observed. The inactivation kinetics for both monoamine oxidase activities A and B showed a biphasic behaviour; a reversible short-term inhibition during the first 5 min of incubation was followed by an irreversible inactivation of the enzyme. The kinetic studies suggest that the slow irreversible inactivation of the monoamine oxidase activities is due to secondary reactions subsequent to the initial attack of the lipoxygenase on the mitochondrial outer membrane. During the interaction of the lipoxygenase with the mitochondria, only about 1.5% of the polyenoic fatty acids present in the mitochondrial membranes were oxygenated. The predominant products formed during the interaction of the lipoxygenase with the mitochondrial membranes are (13S)-hydro(pero)xy-9Z,11E-octadecadienoic acid and (15S)-hydro(pero)xy-5,8,11,13(Z,Z,Z,E)-eicosatetraenoic acid.  相似文献   
516.
Ohne Zusammenfassung  相似文献   
517.
Hydrogels that mimic the natural extracellular matrix (ECM) are used in three-dimensional cell culture, cell therapy, and tissue engineering. A semi-synthetic ECM based on cross-linked hyaluronana offers experimental control of both composition and gel stiffness. The mechanical properties of the ECM in part determine the ultimate cell phenotype. We now describe a rheological study of synthetic ECM hydrogels with storage shear moduli that span three orders of magnitude, from 11 to 3 500 Pa, a range important for engineering of soft tissues. The concentration of the chemically modified HA and the cross-linking density were the main determinants of gel stiffness. Increase in the ratio of thiol-modified gelatin reduced gel stiffness by diluting the effective concentration of the HA component.  相似文献   
518.
519.
An in vitro microscopic fluorescence assay determining the phagocytic activity of isolated plasmatocytes of Galleria mellonella is described. It was developed to quantify insect cellular immune reactions. The assay, a modification of a method originally established for vertebrate blood cells, is based on the quenching effect of trypan blue on fluorescein-isothiocyanate-labelled yeast cells. Only ingested yeast cells retain their fluorescence after quenching and can be easily distinguished from adhering ones. The technique is highly reproducible and easy to perform. Using this method a phagocytosis-stimulating effect caused by a haemolymph fraction > 100 kDa isolated from G. mellonella is demonstrated.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号