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151.
Sofia Cristóvão-Ferreira Sandra H. Vaz Joaquim A. Ribeiro Ana M. Sebastião 《Journal of neurochemistry》2009,109(2):336-347
Neurotransmitter transporters are regulated by phosphorylation but little is known about endogenous substances and receptors that regulate this process. Adenosine is an ubiquitous neuromodulator operating G-protein coupled receptors, which affect the activity of several kinases. We therefore evaluated the influence of adenosine upon the GABA transporter 1 (GAT-1) mediated GABA uptake into hippocampal synaptosomes. Removal of endogenous adenosine (adenosine deaminase, 1 U/mL) decreased GABA uptake, an effect mimicked by blockade of A2A receptors (2-(2-furanyl)-7-(2-phenylethyl)-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine, 50 nM) but not A1 or A2B receptors. A2A receptor activation (4-[2-[[6-amino-9-( N -ethyl-β- d -ribofuranuronamidosyl)-9H-purin-yl]amino]ethyl]benzenepropanoic acid hydrochloride, 3–100 nM) enhanced GABA uptake by increasing the transporter Vmax without change of KM . This was mimicked by adenylate cyclase activation (forskolin, 10 μM) and prevented by protein kinase A (PKA) inhibition ( N -[2-( p -bromocinnamylamino) ethyl]-5-isoquinolinesulfonamide dihydrochloride, 1 μM), which per se did not influence GABA transport. Blockade of protein kinase C (PKC) (2-[1-(3-dimethylaminopropyl)indol-3-yl]-3-(indol-3-yl) maleimide, 1 μM) facilitated GABA transport whereas PKC activation (4-β-phorbol-didecanoate, 250 nM) inhibited it. PKA blockade did not affect the facilitatory action of the PKC inhibitor or the inhibitory action of the PKC activator. However, when adenylate cyclase was activated neither activation nor inhibition of PKC affected GABA uptake. It is concluded that A2A receptors, through activation of the adenylate cyclase/cAMP/PKA transducing pathway facilitate GAT-1 mediated GABA transport into nerve endings by restraining tonic PKC-mediated inhibition. 相似文献
152.
Cínthia C. Bonatto Beatriz S. Magalhães Joaquim O. Branco Edison L. Durigon Luciano P. Silva 《Polar Biology》2009,32(2):287-293
Antarctic biodiversity is evolutionarily complex, reflecting the extreme ambient conditions. Therefore, Antarctic organisms
exhibit sophisticated adaptations in all organization levels, including organs, tissues, and cells. Since red blood cells
(RBCs) travel through the vertebrates blood delivering O2 to all tissues and organs and purging the unwanted CO2, they represent an interesting model to investigate biological adaptations. We have used atomic force microscopy (AFM) to
compare the shape and size of RBCs of the Pygoscelid penguins. A total of 18 landmarks were measured in AFM images. When analyzed
individually, the parameters were not capable of discriminating the RBCs of each species. However, the simultaneous use of
multiple parameters discriminated (74%) among the RBCs. In addition, the use of RBC measurements was sufficient to hierarchically
cluster the species in accordance to other common and reliable phylogenetic strategies. In light of these results, the use
of RBC characters could effectively benefit taxonomic inferences. 相似文献
153.
El-Hachemi Z Escudero C Arteaga O Canillas A Crusats J Mancini G Purrello R Sorrenti A D'Urso A Ribo JM 《Chirality》2009,21(4):408-412
Traces of biological contaminants that cannot be detected, but are expected to be present, in ultra-pure water suffice to select the emerging chiral sign in the spontaneous mirror symmetry breaking that takes place during the formation of the J-aggregates of the amphiphilic diprotonated tetrakis-(4-sulfonatophenyl)porphyrin (H(4)TPPS(4)(2-)). This is demonstrated by competition experiments with a chiral cationic surfactant. The sensitivity of the detection depends on the hierarchical control of the H(4)TPPS(4)(2-) self-aggregation. 相似文献
154.
Heidi Pauer Eliane de Oliveira Ferreira Joaquim dos Santos-Filho Maristela Barbosa Portela Russolina Benedeta Zingali Rosangela Maria Araújo Soares & Regina Maria Cavalcanti Pilotto Domingues 《FEMS immunology and medical microbiology》2009,55(3):388-395
The binding of Bacteroides fragilis to plasmatic fibronectin was investigated using strains isolated from healthy subjects and from patients with bacteremia. They were cultivated in a synthetic media in which variations in cysteine concentrations determined alterations in the oxidation–reduction potential (Eh). All the strains assayed were capable of adhering to plasmatic fibronectin when cultivated under oxidizing and reducing conditions. Bacteroides fragilis 1405 showed the greatest difference when the results under these conditions were compared and it was selected for further investigations. Chemical treatments suggested the involvement of a protein in the interaction between B. fragilis and plasmatic fibronectin. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of outer membrane proteins (OMPs) revealed differences between the extracts obtained from cultures grown under the two conditions. Protein bands of c . 102, 100, 77, 73, 50 and 40 kDa were more highly expressed under oxidizing than reducing conditions. Dot blot analysis showed a stronger recognition of plasmatic fibronectin by OMPs obtained from cultures grown under higher Eh, and Western blot assays confirmed a band of c . 102 kDa as fibronectin-binding protein. This protein was sequenced and revealed to be a putative TonB-dependent OMPs. PCR analysis confirmed the presence of this gene in all the studied strains. 相似文献
155.
Joaquim Casellas Charles R. Farber Rodrigo J. Gularte Kari A. Haus Craig H. Warden Juan F. Medrano 《Mammalian genome》2009,20(5):269-280
Most quantitative trait loci (QTL) studies fail to account for the effect that the maternal genotype may have on an individual’s
phenotypes, even though maternal effect QTL have been shown to account for considerable variation in growth and obesity traits
in mouse models. Moreover, the fetal programming theory suggests that maternal effects influence an offspring’s adult fitness,
although the genetic nature of fetal programming remains unclear. Within this context, our study focused on mapping genomic
regions associated with maternal effect QTL by analyzing the phenotypes of chromosomes 2 and 7 subcongenic mice from genetically
distinct dams. We analyzed 12 chromosome 2 subcongenic strains that spanned from 70 to 180 Mb with CAST/EiJ donor regions
on the background of C57BL/6 J, and 14 chromosome 7 subcongenic strains that spanned from 81 to 111 Mb with BALB/cByJ donor
regions on C57BL/6ByJ background. Maternal QTL analyses were performed on the basis of overlapping donor regions between subcongenic
strains. We identified several highly significant (P < 5 × 10−4) maternal QTL influencing total body weight, organ weight, and fat pad weights in both sets of subcongenics. These QTL accounted
for 1.9-11.7% of the phenotypic variance for growth and obesity and greatly narrowed the genomic regions associated with the
maternal genetic effects. These maternal effect QTL controlled phenotypic traits in adult mice, suggesting that maternal influences
at early stages of development may permanently affect offspring performance. Identification of maternal effects in our survey
of two sets of subcongenic strains, representing approximately 5% of the mouse genome, supports the hypothesis that maternal
effects represent significant sources of genetic variation that are largely ignored in genetic studies. 相似文献
156.
Jordi Alastruey Simon R. Nagel Bettina A. Nier Anthony A.E. Hunt Peter D. Weinberg Joaquim Peiró 《Journal of biomechanics》2009,42(13):2116-2123
Pulse wave propagation in the mature rabbit systemic circulation was simulated using the one-dimensional equations of blood flow in compliant vessels. A corrosion cast of the rabbit circulation was manufactured to obtain arterial lengths and diameters. Pulse wave speeds and inflow and outflow boundary conditions were derived from in vivo data. Numerical results captured the main features of in vivo pressure and velocity pulse waveforms in the aorta, brachiocephalic artery and central ear artery. This model was used to elucidate haemodynamic mechanisms underlying changes in peripheral pulse waveforms observed in vivo after administering drugs that alter nitric oxide synthesis in the endothelial cells lining blood vessels. According to our model, these changes can be explained by single or combined alterations of blood viscosity, peripheral resistance and compliance, and the elasticity of conduit arteries. 相似文献
157.
The estimation of genetic correlations between a nonlinear trait such as longevity and linear traits is computationally difficult on large datasets. A two-step approach was proposed and was checked via simulation. First, univariate analyses were performed to get genetic variance estimates and to compute pseudo-records and their associated weights. These pseudo-records were virtual performances free of all environmental effects that can be used in a BLUP animal model, leading to the same breeding values as in the (possibly nonlinear) initial analyses. By combining these pseudo-records in a multiple trait model and fixing the genetic and residual variances to their values computed during the first step, we obtained correlation estimates by AI-REML and approximate MT-BLUP predicted breeding values that blend direct and indirect information on longevity. Mean genetic correlations and reliabilities obtained on simulated data confirmed the suitability of this approach in a wide range of situations. When nonzero residual correlations exist between traits, a sire model gave nearly unbiased estimates of genetic correlations, while the animal model estimates were biased upwards. Finally, when an incorrect genetic trend was simulated to lead to biased pseudo-records, a joint analysis including a time effect could adequately correct for this bias. 相似文献
158.
Sara Gallego Joaquim Vila José María Nieto Mercedes Urdiain Ramon Rosselló-Móra Magdalena Grifoll 《Systematic and applied microbiology》2010
A Gram-negative bacterium designated UBF-P1T was isolated from an enrichment culture established in nutrient supplemented artificial sea water with pyrene as a carbon source, and inoculated with a marine fuel oil-degrading consortium obtained from a sand sample collected from the beach of Corrubedo (A Coruña, Galicia, Spain) after the Prestige accidental oil spill. Phylogenetic analysis based on the almost complete 16S rRNA gene sequence affiliated strain UBF-P1T with the family Cohaesibacteraceae, Cohaesibacter gelatinilyticus (DSM 18289T) being the closest relative species with 92% sequence similarity. Cells were irregular rods, motile, strictly aerobic, catalase and oxidase positive. Ubiquinone 10 was the major respiratory lipoquinone. The major polar lipids comprised diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), phosphatidylmonomethylethanolamine (PME), and phosphatidylcholine (PC). The major fatty acids detected were C18:1ω7c, C19:0 cycloω8c, and C16:0. The G + C content of strain UBF-P1T was 63.9 mol%. The taxonomic comparison with the closest relative based on genotypic, phenotypic and chemotaxonomic characteristics supported that strain UBF-P1T could be classified as a novel genus and species, for which the name Breoghania corrubedonensis gen. nov., sp. nov. is proposed. The type strain of this new taxon is UBF-P1T (CECT 7622, LMG 25482, DSM 23382). 相似文献
159.
Marco P.C. Marques Carla C.C.R. de Carvalho Joaquim M.S. Cabral Pedro Fernandes 《Biotechnology and bioengineering》2010,106(4):619-626
The use of whole cells is becoming a more common approach in pharmaceutical and agrochemical industries in order to obtain pure compounds with fewer production steps, higher yields, and cleaner processes, as compared to those achieved with traditional strategies. Whole cells are often used as enzymes pools, in particular when multi‐step reactions and/or co‐factor regeneration are envisaged. Nonetheless, published information on the scale‐up of such systems both in aqueous and in two‐phase aqueous–organic systems is relatively scarce. The present work aims to evaluate suitable scale‐up criteria in conventional and non‐conventional medium for a whole‐cell bioconversion that uses resting cells of Mycobacterium sp. NRRL B‐3805 to cleave the side chain of β‐sitosterol, a poorly water‐soluble substrate. The experiments were performed in 24‐well microtiter plates and in 250 mL shaken flasks as orbital stirred systems, and in 300 mL stirred tanks as mechanically stirred systems. Results show that productivity yields were similar in all scales tested, when maintaining oxygen mass transfer coefficients constant in aqueous systems, or when maintaining constant volumetric power consumption in aqueous–organic two‐phase systems. Biotechnol. Bioeng. 2010;106: 619–626. © 2010 Wiley Periodicals, Inc. 相似文献
160.