全文获取类型
收费全文 | 323篇 |
免费 | 10篇 |
国内免费 | 11篇 |
出版年
2024年 | 2篇 |
2023年 | 1篇 |
2022年 | 11篇 |
2021年 | 8篇 |
2020年 | 6篇 |
2019年 | 9篇 |
2018年 | 16篇 |
2017年 | 4篇 |
2016年 | 28篇 |
2015年 | 65篇 |
2014年 | 51篇 |
2013年 | 34篇 |
2012年 | 20篇 |
2011年 | 10篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 11篇 |
2007年 | 11篇 |
2006年 | 8篇 |
2005年 | 10篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1986年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有344条查询结果,搜索用时 15 毫秒
21.
22.
J.A. Poveda A.M. GiudiciM.L. Renart M.L. MolinaE. Montoya A. Fernández-CarvajalG. Fernández-Ballester J.A. EncinarJ.M. González-Ros 《生物化学与生物物理学报:生物膜》2014
Ion channel conformational changes within the lipid membrane are a key requirement to control ion passage. Thus, it seems reasonable to assume that lipid composition should modulate ion channel function. There is increasing evidence that this implicates not just an indirect consequence of the lipid influence on the physical properties of the membrane, but also specific binding of selected lipids to certain protein domains. The result is that channel function and its consequences on excitability, contractility, intracellular signaling or any other process mediated by such channel proteins, could be subjected to modulation by membrane lipids. From this it follows that development, age, diet or diseases that alter lipid composition should also have an influence on those cellular properties. The wealth of data on the non-annular lipid binding sites in potassium channel from Streptomyces lividans (KcsA) makes this protein a good model to study the modulation of ion channel structure and function by lipids. The fact that this protein is able to assemble into clusters through the same non-annular sites, resulting in large changes in channel activity, makes these sites even more interesting as a potential target to develop lead compounds able to disrupt such interactions and hopefully, to modulate ion channel function. This Article is Part of a Special Issue Entitled: Membrane Structure and Function: Relevance in the Cell's Physiology, Pathology and Therapy. 相似文献
23.
Fabien Gosselet Julien Saint-PolLaurence Fenart 《Biochemical and biophysical research communications》2014
Altered brain cholesterol homeostasis plays a key role in neurodegenerative diseases such as Alzheimer’s disease (AD). For a long time, the blood–brain barrier (BBB) was basically considered as a barrier isolating the brain from circulating cholesterol, however, several lines of evidence now suggest that the BBB strictly regulates the exchanges of sterol between the brain and the peripheral circulation. Oxysterols, synthesized by neurons or by peripheral cells, cross the BBB easily and modulate the expression of several enzymes, receptors and transporters which are involved not only in cholesterol metabolism but also in other brain functions. This review article deals with the way oxysterols impact BBB cells. These perspectives open new routes for designing certain therapeutical approaches that target the BBB so that the onset and/or progression of brain diseases such as AD may be modulated. 相似文献
24.
Ricardo Cabrera 《Archives of biochemistry and biophysics》2010,502(1):23-30
Phosphofructokinase-2 (Pfk-2) belongs to the ribokinase family and catalyzes the ATP-dependent phosphorylation of fructose-6-phosphate, showing allosteric inhibition by a second ATP molecule. Several structures have been deposited on the PDB for this family of enzymes. A structure-based multiple sequence alignment of a non-redundant set of these proteins was used to infer phylogenetic relationships between family members with different specificities and to dissect between globally conserved positions and those common to phosphosugar kinases. We propose that phosphosugar kinases appeared early in the evolution of the ribokinase family. Also, we identified two conserved sequence motifs: the TR motif, not described previously, present in phosphosugar kinases but not in other members of the ribokinase family, and the globally conserved GXGD motif. Site-directed mutagenesis of R90 and D256 present in these motifs, indicate that R90 participates in the binding of the phosphorylated substrate and that D256 is involved in the phosphoryl transfer mechanism. 相似文献
25.
Ricardo Z. Lorenzon Carlos E.L. Cunha Marcelo F. Marcondes Maria A. Juliano Luiz R. Travassos Adriana K. Carmona 《Archives of biochemistry and biophysics》2010,500(2):131-136
Oligopeptidase A (OpdA) belongs to the M3A subfamily of bacterial peptidases with catalytic and structural properties similar to mammalian thimet-oligopeptidase (TOP) and neurolysin (NEL). The three enzymes have four conserved Tyr residues on a flexible loop in close proximity to the catalytic site. In OpdA, the flexible loop is formed by residues 600-614 (600SHIFAGGYAAGYYSY614). Modeling studies indicated that in OpdA the Tyr607 residue might be involved in the recognition of the substrate with a key role in catalysis. Two mutants were constructed replacing Tyr607 by Phe (Y607F) or Ala (Y607A) and the influence of the site-directed mutagenesis in the catalytic process was examined. The hydrolysis of Abz-GXSPFRQ-EDDnp derivatives (Abz = ortho-aminobenzoic acid; EDDnp N-[2,4-dinitrophenyl]-ethylenediamine; X = different amino acids) was studied to compare the activities of wild-type OpdA (OpdA WT) and those of Y607F and Y607A mutants The results indicated that OpdA WT cleaved all the peptides only on the X-S bond whereas the Y607F and Y607A mutants were able to hydrolyze both the X-S and the P-F bonds. The kinetic parameters showed the importance of Tyr607 in OpdA catalytic activity as its substitution promoted a decrease in the kcat/Km value of about 100-fold with Y607F mutant and 1000-fold with Y607A. Both mutations, however, did not affect protein folding as indicated by CD and intrinsic fluorescence analysis. Our results indicate that the OpdA Tyr607 residue plays an important role in the enzyme-substrate interaction and in the hydrolytic activity. 相似文献
26.
27.
Four species of the ant genus Ponera Latreille, 1804, are recorded from India. The present study reports one new species Ponera
sikkimensis
sp. n., a divergent population of Ponera
indica Bharti & Wachkoo, 2012 and one new record, Ponera
paedericera Zhou, 2001 from India. An identification key and distributions for the four known Indian species of Ponera based on the worker caste are provided. 相似文献
28.
The genus Zachobiella Banks, 1920 is reviewed and a new species Zachobiella
yunanica
sp. n. described from China. All species found in China are redescribed, and Zachobiella
submarginata Esben-Petersen, 1929 is recorded from China for the first time. A key to the adults of Zachobiella is provided. 相似文献
29.
30.
A new tortoise beetle species, Cyrtonota
abrili, is described from the Antioquia and Caldas departments in Colombia. New faunistic data are provided for 87 species, including 16 new additions to the country’s fauna. A checklist of the known 238 species of tortoise beetles recorded from Colombia is given. 相似文献