全文获取类型
收费全文 | 962篇 |
免费 | 56篇 |
国内免费 | 1篇 |
出版年
2024年 | 1篇 |
2023年 | 11篇 |
2022年 | 30篇 |
2021年 | 45篇 |
2020年 | 58篇 |
2019年 | 103篇 |
2018年 | 66篇 |
2017年 | 57篇 |
2016年 | 54篇 |
2015年 | 53篇 |
2014年 | 49篇 |
2013年 | 89篇 |
2012年 | 80篇 |
2011年 | 55篇 |
2010年 | 45篇 |
2009年 | 39篇 |
2008年 | 40篇 |
2007年 | 42篇 |
2006年 | 22篇 |
2005年 | 23篇 |
2004年 | 27篇 |
2003年 | 11篇 |
2002年 | 13篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
排序方式: 共有1019条查询结果,搜索用时 15 毫秒
941.
Alireza Poshtkohi John Wade Liam McDaid Junxiu Liu Mark Dallas Angela Bithell 《PLoS computational biology》2021,17(11)
Regulation of cytosolic calcium (Ca2+) dynamics is fundamental to microglial function. Temporal and spatial Ca2+ fluxes are induced from a complicated signal transduction pathway linked to brain ionic homeostasis. In this paper, we develop a novel biophysical model of Ca2+ and sodium (Na+) dynamics in human microglia and evaluate the contribution of purinergic receptors (P2XRs) to both intracellular Ca2+ and Na+ levels in response to agonist/ATP binding. This is the first comprehensive model that integrates P2XRs to predict intricate Ca2+ and Na+ transient responses in microglia. Specifically, a novel compact biophysical model is proposed for the capture of whole-cell patch-clamp currents associated with P2X4 and P2X7 receptors, which is composed of only four state variables. The entire model shows that intricate intracellular ion dynamics arise from the coupled interaction between P2X4 and P2X7 receptors, the Na+/Ca2+ exchanger (NCX), Ca2+ extrusion by the plasma membrane Ca2+ ATPase (PMCA), and Ca2+ and Na+ leak channels. Both P2XRs are modelled as two separate adenosine triphosphate (ATP) gated Ca2+ and Na+ conductance channels, where the stoichiometry is the removal of one Ca2+ for the hydrolysis of one ATP molecule. Two unique sets of model parameters were determined using an evolutionary algorithm to optimise fitting to experimental data for each of the receptors. This allows the proposed model to capture both human P2X7 and P2X4 data (hP2X7 and hP2X4). The model architecture enables a high degree of simplicity, accuracy and predictability of Ca2+ and Na+ dynamics thus providing quantitative insights into different behaviours of intracellular Na+ and Ca2+ which will guide future experimental research. Understanding the interactions between these receptors and other membrane-bound transporters provides a step forward in resolving the qualitative link between purinergic receptors and microglial physiology and their contribution to brain pathology. 相似文献
942.
943.
Cytotechnology - Physical methods are widely utilized to deliver nucleic acids into cells such as electro-transfection or heat shock. An efficient gene electro-transfection requires the best... 相似文献
944.
Mahtab Yarmohammadi Mohammad Pourkazemi Rezvanollah Kazemi Ali Hallajian Hassan Soltanloo Mohammad Hassanzadeh Saber Alireza Abbasalizadeh 《Journal of applied genetics》2014,55(2):239-247
The effects of different periods of starvation (1, 2, 3, and 4 weeks) and subsequent re-feeding (over a 4 week) on the compensatory growth performance and insulin-like growth factor I (IGF-I) mRNA expression in liver and white muscle were investigated in juvenile Persian sturgeon (Acipenser persicus). First, a fragment of 617 nucleotides coding for IGF-I was cloned from liver, which included an open reading frame of 486 nucleotides, encoding a 162 amino acid preproIGF-I. This is composed of a 45 aa for signal peptide, a 117 aa for the mature peptide comprising the B, C, A, and D domains, and a 47 aa for E domain. The mature Persian sturgeon IGF-I exhibits high sequence identities with other sturgeon species and teleost, ranging between 68 and 95 %. The pattern of IGF-I mRNA expression in the liver and white muscle was measured in response to different periods of starvation and subsequent re-feeding. Nutritional status influenced IGF-I mRNA expression pattern in both liver and muscle. IGF-I mRNA expression in the liver increased during starvation, before decreasing after re-feeding. Furthermore, white muscle IGF-I mRNA expression showed better responses to nutritional status and decreased following starvation and increased by re-feeding. However, changes in the expression of IGF-I mRNA were not significantly different between any of the treatments in both tissues. These data suggest that muscle and liver IGF-I mRNA expression do not have a regulatory role for somatic growth induced by compensatory growth in Persain sturgeon. 相似文献
945.
Alireza Zamani Zahra Nikmagham Maryam Allahdadi Fereshteh Ghassemzadeh 《Zoology in the Middle East.》2013,59(4):362-367
We present the results of some spider surveys that were conducted in different parts of Iran. Faunistic records for 30 species which are new to Iran are presented here. Biogeographic data are provided for each species. Two families, namely Liocranidae and Mimetidae, are recorded for the first time from the country. 相似文献
946.
947.
Diazinon insecticide is widely applied in rice (Oryza sativa L.) fields in Iran. However, concerns are now being raised about its potential adverse impacts on rice. In this study, a time-course metabolic change in rice plants was investigated after diazinon treatment using gas chromatography-mass spectrometry (GC-MS) and subsequently three different methods, MetaboAnalyst, MetaboNetwork, and analysis of reporter reactions, as a potential multivariate method were used to find the underlying changes in metabolism with stronger evidence in order to link differentially expressed metabolites to biological pathways. Results clearly showed the similarity of acetylcholinesterase (AChE) of rice plants to that of animals in terms of its inhibitability by diazinon and emphasized that subsequent accumulation of AChE mainly affects the metabolism of osmolites and tricarboxylic acid intermediates subsequent accumulation of ACh mainly affects the metabolism of osmolites and TCA intermediates. 相似文献
948.
Genetic variation and evolutionary origins of parthenogenetic Artemia (Crustacea: Anostraca) with different ploidies 下载免费PDF全文
Using two nuclear (ITS1 and Na+/K+ ATPase) and three mitochondrial (COI, 16S and 12S) markers, we determined the genetic variation and evolutionary relationship of parthenogenetic and bisexual Artemia. Our analyses revealed that mitochondrial genes had higher genetic variation than nuclear genes and that the 16S showed more variety than the other mitochondrial genes in parthenogenetic populations. Triploid parthenogens showed lower genetic variation than diploid ones, whereas the tetra‐ and pentaploids had greater genetic distance than diploid parthenogens. No shared haplotype was found between individuals of parthenogenetic populations and Asian bisexual species with the exception of Na+/K+ ATPase (Artemia tibetiana). Only mitochondrial markers can demonstrate phylogenetic relationships, and showed that the parthenogenetic Artemia is a polyphyletic group in which the diploid lineages share a common ancestor with Artemia urmiana while tetraploids are closely related to Artemia sinica. The triploid and pentaploid linages are likely to be directly derived from diploid and tetraploid parthenogens, respectively. Subsequently, west Asia is origin for di‐/triploids, and tetra‐/pentaploids rose from East Asia. 相似文献
949.
In simulations of carbon materials it is common practice to view the coefficients of the cutoff function as free parameters which can be optimised according to the system of interest. This work examines a common modification to the widely used Tersoff potential in which the coefficient of the upper cutoff is increased to improve the properties of amorphous carbon. Using molecular dynamics simulations, we show that this so-called extended cutoff Tersoff model leads to nucleation of diamond nanocrystals during annealing of amorphous carbon. By varying the density of the system, and examining the radial distribution function in conjunction with the modified cutoff function, we demonstrate that this behaviour is unphysical, and does not represent a new pathway for synthesising diamond. Viewed from a broader perspective, this observation provides a cautionary tale against altering the parameters of empirical potentials without fully considering the wider implications. 相似文献
950.
Generation of Insulin‐Producing Cells From Human‐Induced Pluripotent Stem Cells Using a Stepwise Differentiation Protocol Optimized With Platelet‐Rich Plasma 下载免费PDF全文