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271.
Different mechanisms that could form the molecular basis for bi-directional synaptic plasticity have been identified experimentally
and corresponding biophysical models can be constructed. However, such models are complex and therefore it is hard to deduce
their consequences to compare them to existing abstract models of synaptic plasticity. In this paper we examine two such models:
a phenomenological one inspired by the phenomena of AMPA receptor insertion, and a more complex biophysical model based on
the phenomena of AMPA receptor phosphorylation. We show that under certain approximations both these models can be mapped
on to an equivalent, calcium-dependent, differential equation. Intracellular calcium concentration varies locally in each
postsynaptic compartment, thus the plasticity rule we extract is a single-synapse rule. We convert this single synapse plasticity
equation to a multi-synapse rule by incorporating a model of the NMDA receptor. Finally we suggest a mathematical embodiment
of metaplasticity, which is consistent with observations on NMDA receptor properties and dependence on cellular activity.
These results, in combination with some of our previous results, produce converging evidence for the calcium control hypothesis
including a dependence of synaptic plasticity on the level of intercellular calcium as well as on the temporal pattern of
calcium transients.
Received: 24 April 2002 / Accepted: 15 May 2002
Acknowledgements. LCY was supported by a Burroughs Wellcome fellowship, GCC by Murst 60%.
Correspondence to: H. Z. Shouval (e-mail: Harel_Shouval@brown.edu) 相似文献
272.
Is 1-hydroxypyrene a reliable bioindicator of measured dietary polycyclic aromatic hydrocarbon under normal conditions? 总被引:3,自引:0,他引:3
Viau C Diakité A Ruzgyté A Tuchweber B Blais C Bouchard M Vyskocil A 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2002,778(1-2):165-177
Five healthy volunteers consumed similar amounts of identical foods for 5 consecutive days. The concentration of pyrene and of benzo(a)pyrene was determined in each of the 15 meals by a short analytical method that included sample saponification, solvent extraction, and HPLC analysis. The volunteers also provided three daily total volume 8-h urine samples for the duration of the study for the assessment of 1-hydroxypyrene, a biomarker of pyrene and polycyclic aromatic hydrocarbon (PAH) exposure. Mean recoveries were 83 and 75%, respectively, for pyrene and benzo(a)pyrene in food. Daily dietary pyrene doses varied from 0.7 to 3 microg. Excluding two outliers consisting of meals containing charbroiled pork and beef, pyrene content in the meals estimated from the published literature data was correlated to the measured pyrene, but overestimated the actual concentration by ca. 70%. Despite the identical ingested doses of pyrene, there was a 50-76% (coefficient of variation) interindividual variability in the daily-excreted amount of 1-hydroxypyrene. Urinary excretion of this metabolite was not correlated with ingested dose of pyrene under the normal feeding conditions used in this study. Bioavailability, enzymatic polymorphism, and differences in enterohepatic cycling of the metabolite may contribute to the observed variability. It was calculated that dietary pyrene intake accounts for between 87.5 and 99.8% of the sum of dietary and inhalation intake. From the presented data, unless the above-mentioned factors are taken into account, 1-hydroxypyrene might not be a reliable bioindicator of ingested pyrene (PAHs) under normal feeding conditions. 相似文献
273.
Activating transcription factor 4 is translationally regulated by hypoxic stress 总被引:10,自引:0,他引:10 下载免费PDF全文
Blais JD Filipenko V Bi M Harding HP Ron D Koumenis C Wouters BG Bell JC 《Molecular and cellular biology》2004,24(17):7469-7482
274.
Role of specific CCAAT/enhancer-binding protein isoforms in intestinal epithelial cells 总被引:3,自引:0,他引:3
Gheorghiu I Deschênes C Blais M Boudreau F Rivard N Asselin C 《The Journal of biological chemistry》2001,276(47):44331-44337
275.
Tamazight Cherifi Catherine Carrillo Dominic Lambert Ilhem Miniaï Sylvain Quessy Guillaume Larivière-Gauthier Burton Blais Philippe Fravalo 《BMC microbiology》2018,18(1):220
Background
The aim of this study was to characterize the genomes of 30?Listeria monocytogenes isolates collected at a pig slaughterhouse to determine the molecular basis for their persistence.Results
Comparison of the 30?L. monocytogenes genomes showed that successive isolates (i.e., persistent types) recovered from thew sampling site could be linked on the basis of single nucleotide variants confined to prophage regions. In addition, our study revealed the presence among these strains of the bcrABC cassette which is known to produce efflux pump-mediated benzalkonium chloride resistance, and which may account for the persistence of these isolates in the slaughterhouse environment. The presence of the bcrABC cassette was confirmed by WGS and PCR and the resistance phenotype was determined by measuring minimum inhibitory concentrations. Furthermore, the BC-resistant strains were found to produce lower amounts of biofilm in the presence of sublethal concentrations of BC.Conclusions
High resolution SNP-based typing and determination of the bcrABC cassette may provide a means of distinguishing between resident and sporadic L. monocytogenes isolates, and this in turn will support better management of this pathogen in the food industry.276.
Jéronime Marie-Ange Sènami Ouachinou Gbèwonmèdéa Hospice Dassou Akomian Fortuné Azihou Aristide Cossi Adomou Hounnankpon Yédomonhan 《Journal of ethnobiology and ethnomedicine》2018,14(1):66
Background
We undertook ethnobotanical and ecological studies on fodder plants grazed by cattle across Benin national area. The study aims to ascertain the top priority fodder plants in order to catalogue the indigenous knowledge regarding their use.Methods
Data were collected through semi-structured interviews and covered 690 breeders and 40 days of pasture walk. These were analysed using similarity index of Jaccard (IS), relative frequency citation (RFC) and fodder value during pasture walk (FVPW).Results
We documented a total of 257 fodder plant species, of which 116 recorded during ethnobotanical investigations and 195 during pasture walk. These species belong to 181 genera and 54 families. Both methods shared 52 species. Leaves (58%) and leafy stem (28%) were the most grazed parts of plant. The most common species used as fodder included Andropogon gayanus, Panicum maximum, Pterocarpus erinaceus and Flueggea virosa. The top species with a highest FVPW were Panicum maximum and Pterocarpus erinaceus. A total of 16 species were considered as top fodder plants in Benin.Conclusions
The wide diversity of plants reported indicates that there is a number of promising fodder species in the flora of Benin. The insight gained in this study relating to bovine feeds could guide in the selection and introduction of feed innovations that could improve livestock production.277.
278.
Nathalie Pavy France Gagnon Philippe Rigault Sylvie Blais Astrid Deschênes Brian Boyle Betty Pelgas Marie Deslauriers Sébastien Clément Patricia Lavigne Manuel Lamothe Janice E.K. Cooke Juan P. Jaramillo‐Correa Jean Beaulieu Nathalie Isabel John Mackay Jean Bousquet 《Molecular ecology resources》2013,13(2):324-336
High‐density SNP genotyping arrays can be designed for any species given sufficient sequence information of high quality. Two high‐density SNP arrays relying on the Infinium iSelect technology (Illumina) were designed for use in the conifer white spruce (Picea glauca). One array contained 7338 segregating SNPs representative of 2814 genes of various molecular functional classes for main uses in genetic association and population genetics studies. The other one contained 9559 segregating SNPs representative of 9543 genes for main uses in population genetics, linkage mapping of the genome and genomic prediction. The SNPs assayed were discovered from various sources of gene resequencing data. SNPs predicted from high‐quality sequences derived from genomic DNA reached a genotyping success rate of 64.7%. Nonsingleton in silico SNPs (i.e. a sequence polymorphism present in at least two reads) predicted from expressed sequenced tags obtained with the Roche 454 technology and Illumina GAII analyser resulted in a similar genotyping success rate of 71.6% when the deepest alignment was used and the most favourable SNP probe per gene was selected. A variable proportion of these SNPs was shared by other nordic and subtropical spruce species from North America and Europe. The number of shared SNPs was inversely proportional to phylogenetic divergence and standing genetic variation in the recipient species, but positively related to allele frequency in P. glauca natural populations. These validated SNP resources should open up new avenues for population genetics and comparative genetic mapping at a genomic scale in spruce species. 相似文献
279.
Roberto Esposito Franco Cilli Valentina Pieramico Antonio Ferretti Antonella Macchia Marco Tommasi Aristide Saggino Domenico Ciavardelli Antonietta Manna Riccardo Navarra Filippo Cieri Liborio Stuppia Armando Tartaro Stefano L. Sensi 《PloS one》2013,8(7)
Background
There is growing debate on the use of drugs that promote cognitive enhancement. Amphetamine-like drugs have been employed as cognitive enhancers, but they show important side effects and induce addiction. In this study, we investigated the use of modafinil which appears to have less side effects compared to other amphetamine-like drugs. We analyzed effects on cognitive performances and brain resting state network activity of 26 healthy young subjects.Methodology
A single dose (100 mg) of modafinil was administered in a double-blind and placebo-controlled study. Both groups were tested for neuropsychological performances with the Raven’s Advanced Progressive Matrices II set (APM) before and three hours after administration of drug or placebo. Resting state functional magnetic resonance (rs-FMRI) was also used, before and after three hours, to investigate changes in the activity of resting state brain networks. Diffusion Tensor Imaging (DTI) was employed to evaluate differences in structural connectivity between the two groups. Protocol ID: Modrest_2011; ; http://clinicaltrials.gov/ct2/show/ NCT01684306. NCT01684306Principal Findings
Results indicate that a single dose of modafinil improves cognitive performance as assessed by APM. Rs-fMRI showed that the drug produces a statistically significant increased activation of Frontal Parietal Control (FPC; p<0.04) and Dorsal Attention (DAN; p<0.04) networks. No modifications in structural connectivity were observed.Conclusions and Significance
Overall, our findings support the notion that modafinil has cognitive enhancing properties and provide functional connectivity data to support these effects.Trial Registration
ClinicalTrials.gov http://clinicaltrials.gov/ct2/show/ NCT01684306. NCT01684306相似文献280.
Prem Kumarathasan Renaud Vincent Erica Blais Anu Saravanamuthu Pallavi Gupta Heather Wyatt Ronald Mitchel Mohammed Hannan Akilesh Trivedi Stewart Whitman 《PloS one》2013,8(6)