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101.
Two GacA-dependent small RNAs modulate the quorum-sensing response in Pseudomonas aeruginosa 总被引:3,自引:0,他引:3 下载免费PDF全文
Kay E Humair B Dénervaud V Riedel K Spahr S Eberl L Valverde C Haas D 《Journal of bacteriology》2006,188(16):6026-6033
In Pseudomonas aeruginosa, the GacS/GacA two-component system positively controls the quorum-sensing machinery and the expression of extracellular products via two small regulatory RNAs, RsmY and RsmZ. An rsmY rsmZ double mutant and a gacA mutant were similarly impaired in the synthesis of the quorum-sensing signal N-butanoyl-homoserine lactone, the disulfide bond-forming enzyme DsbA, and the exoproducts hydrogen cyanide, pyocyanin, elastase, chitinase (ChiC), and chitin-binding protein (CbpD). Both mutants showed increased swarming ability, azurin release, and early biofilm development. 相似文献
102.
Cytoprotective Effect of <Emphasis Type="Italic">Valeriana officinalis</Emphasis> Extract on an In Vitro Experimental Model of Parkinson Disease 总被引:1,自引:1,他引:0
de Oliveria DM Barreto G De Andrade DV Saraceno E Aon-Bertolino L Capani F Dos Santos El Bachá R Giraldez LD 《Neurochemical research》2009,34(2):215-220
Parkinson′s disease (PD) is one of the most important neurodegenerative worldwide disorders. The potential cytoprotective
effects of aqueous extract of Valeriana officinalis on rotenone-induced apoptosis in human neuroblastoma SH-SY5Y cells were demonstrated. The cytotoxicity, cell viability and
analysis of cellular morphology were performed by MTT-tetrazole (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide)
assay and phase contrast microscopy, respectively. Significant changes in the cellular morphology, and condensation of the
cell body could be observed when cells were treated with 300 nM rotenone for 48 h. Three different concentrations of Valeriana officinalis extract were used (0.049, 0.098 and 0.195 mg/mL). These extracts brought about an increase of 7.0 ± 1.3%, 14.5 ± 1.3% and
14.5 ± 3.2% in cell viability. Our results indicated that neuroprotector action of the Valeriana officinalis extract provides support for later studies as they help understanding this drug for the development of cytoprotective various
therapies in PD. 相似文献
103.
Mario PL Calus Theo HE Meuwissen Jack J Windig Egbert F Knol Chris Schrooten Addie LJ Vereijken Roel F Veerkamp 《遗传、选种与进化》2009,41(1):11
The aim of this paper was to compare the effect of haplotype definition on the precision of QTL-mapping and on the accuracy of predicted genomic breeding values. In a multiple QTL model using identity-by-descent (IBD) probabilities between haplotypes, various haplotype definitions were tested i.e. including 2, 6, 12 or 20 marker alleles and clustering base haplotypes related with an IBD probability of > 0.55, 0.75 or 0.95. Simulated data contained 1100 animals with known genotypes and phenotypes and 1000 animals with known genotypes and unknown phenotypes. Genomes comprising 3 Morgan were simulated and contained 74 polymorphic QTL and 383 polymorphic SNP markers with an average r2 value of 0.14 between adjacent markers. The total number of haplotypes decreased up to 50% when the window size was increased from two to 20 markers and decreased by at least 50% when haplotypes related with an IBD probability of > 0.55 instead of > 0.95 were clustered. An intermediate window size led to more precise QTL mapping. Window size and clustering had a limited effect on the accuracy of predicted total breeding values, ranging from 0.79 to 0.81. Our conclusion is that different optimal window sizes should be used in QTL-mapping versus genome-wide breeding value prediction. 相似文献
104.
Paluszkiewicz P Zgrajka W Saran T Schabowski J Piedra JL Fedkiv O Rengman S Pierzynowski SG Turski WA 《Amino acids》2009,37(4):637-641
Kynurenic acid (KYNA) is an agonist of the G-protein-coupled receptor GPR35, which is predominantly expressed in gastrointestinal
tissues. The aim of this study was to determine the content of KYNA in gastric juice, bile and pancreatic juice and intestinal
content. KYNA was determined by means of high performance liquid chromatography. The mean concentrations of KYNA in human
gastric juice is 9.91 ± 0.71 nM in contrast to human bile (832.5 ± 204.1 and 306.8 ± 35.2 nM) obtained from patients with
cholecystolithiasis and obstructive jaundice, respectively. In pigs, the KYNA levels in bile and pancreatic juice are 1,113.3 ± 63.34
and 757.0 ± 394.4 nM, respectively. The KYNA concentration increases along the digestive system, reaching 1,638 nM in the
colon content. We suggest that the liver and pancreas affect the content of kynurenic acid in the lumen of the digestive tract. 相似文献
105.
L. Vega M. Valverde G. Elizondo J.F. Leyva E. Rojas 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》2009,679(1-2):39-43
Organophosphorous (OP) compounds are the most commonly used pesticides. There are several published reports on the direct toxicity of OP pesticides, but few data on the toxicity of their metabolites. To determine if diethylthiophosphate (DETP) and diethyldithiophosphate (DEDTP), two of the major OP metabolites, demonstrate genotoxicity, and to elucidate the possible genotoxic mechanisms, we treated WRL68, HepG2, HeLa and human blood cells with different concentrations of DETP and DEDTP. We evaluated the possible contribution of oxidative stress generation and P450 enzymes to the genotoxicity of the OP metabolites, as determined using the comet assay. Our results showed that both OP metabolites (DETP and DEDTP) induce DNA damage only in the hepatic cell lines, and this effect could be related to a secondary non-diffusible metabolite generated by the activity of P450 enzymes since P450 enzyme inhibitors also inhibited the induction of DNA damage in hepatic cells. These secondary metabolites should be taken into account when assessing risk to human populations exposed to OP pesticides. 相似文献
106.
107.
Encarna Velázquez Angel Valverde Raúl Rivas Víctor Gomis Álvaro Peix Inne Gantois José M. Igual Milagros León-Barrios Anne Willems Pedro F. Mateos Eustoquio Martínez-Molina 《Antonie van Leeuwenhoek》2010,97(4):363-376
In this work we analysed different chromosomal and symbiotic markers in rhizobial strains nodulating Lupinus albus (white lupin) in several continents. Collectively the analysis of their rrs and atpD genes, and 16S-23S intergenic spacers (ITS), showed that they belong to at least four chromosomal lineages within the genus Bradyrhizobium. Most isolates from the Canary Islands (near to the African continent) grouped with some strains isolated on mainland Spain and were identified as Bradyrhizobium canariense. These strains are divided into two ITS subgroups coincident with those previously described from isolates nodulating Ornithopus. The remaining strains isolated on mainland Spain grouped with most isolates from Chile (American continent) forming a new lineage related to Bradyrhizobium japonicum. The strains BLUT2 and ISLU207 isolated from the Canary Islands and Chile, respectively, formed two new lineages phylogenetically close to different species of Bradyrhizobium depending on the marker analyzed. The analysis of the nodC gene showed that all strains nodulating L. albus belong to the biovar genistearum; nevertheless they form four different nodC lineages of which lineage C is at present exclusively formed by L. albus endosymbionts isolated from different continents. 相似文献
108.
Pablo Corcuera Pedro Luis Valverde José Alejandro Zavala-Hurtado Gabriela De la Rosa César Gabriel-Durán 《Journal of Insect Conservation》2010,14(6):711-719
Eucalyptus spp. are commonly planted, forming non-native plantations, including the tropics and their wildlife conservation value is
relatively unknown. Recent studies have concluded that secondary forests and tree plantations are less diverse than well-developed
tropical rain forests. However, introduced Eucalyptus stands harbored similar species richness to surrounding native woodland in temperate woodlands in North America though the
identity of the species present may differ. Species composition, as well as dominance curves and differences in community
structure add additional insight to understanding faunistic responses to replacement of native woodland by Eucalyptus plantations. Here, we compared species richness, diversity patterns, and the distribution of non-weaving spiders between
native woodlands and Eucalyptus plantations in a temperate region of Mexico. We found more Lycosidae species in all plantation stands. Other community attributes were not consistently different between plantations and native
woodlands. This is explained by similarities between, and differences within, the understory of the two main vegetation types.
Multivariate analyses identified three spider groups and five spider species could be identified as indicators of these groups.
A comparison of the number of species of the wandering spiders between the two vegetation types suggests a compensation pattern
that is reported here for the first time. 相似文献
109.
Bernardo Nuche‐Berenguer Sergio Portal‐Núñez Paola Moreno Nieves González Alicia Acitores Ana López‐Herradón Pedro Esbrit Isabel Valverde María L. Villanueva‐Peñacarrillo 《Journal of cellular physiology》2010,225(2):585-592
Glucagon‐like peptide 1 (GLP‐1) controls glucose metabolism in extrapancreatic tissues through receptors other than the pancreatic cAMP‐linked GLP‐1 receptor; also, GLP‐1 induces an insulin‐ and PTH‐independent bone anabolic action in insulin‐resistant and type‐2 diabetic rats. Here we searched for the presence and characteristics of GLP‐1 receptors in osteoblastic MC3T3‐E1 cells. [125I]‐GLP‐1 specific binding to MC3T3‐E1 cells was time‐ and temperature‐dependent, reaching maximal value at 30 min at 25°C; in these conditions, [125I]‐GLP‐1 binding was dissociable, and displaced by GLP‐1, partially by GLP‐2, but not by exendin‐4 (Ex‐4), exendin‐9 (Ex‐9), glucagon or insulin; Scatchard analysis of the unlabeled GLP‐1 data showed high and low affinity binding sites; cross‐linking of GLP‐1 binding revealed an estimated 70 kDa band, almost undetectable in the presence of 10?6 M GLP‐1. GLP‐1, Ex‐9, insulin or glucagon failed to modify cellular cAMP content, while GLP‐2 and Ex‐4 increased it. However, GLP‐1 induced an immediate hydrolysis of glycosylphosphatidylinositols (GPIs) generating short‐lived inositolphosphoglycans (IPGs), and an increase in phosphatidylinositol‐3 kinase (PI3K) and mitogen activated protein kinase (MAPK) activities; Ex‐4 also affected GPIs, but its action was delayed with respect to that of GLP‐1. This incretin was found to decrease Runx2 but increased osteocalcin gene expression, without affecting that of osteoprotegerin or the canonical Wnt pathway activity in MC3T3‐E1 cells which do not express the pancreatic GLP‐1 receptor. Our data demonstrate for the first time that GLP‐1 can directly and functionally interact with osteoblastic cells, possibly through a GPI/IPG‐coupled receptor. J. Cell. Physiol. 225: 585–592, 2010. © 2010 Wiley‐Liss, Inc. 相似文献