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排序方式: 共有333条查询结果,搜索用时 15 毫秒
41.
Ansari FL Umbreen S Hussain L Makhmoor T Nawaz SA Lodhi MA Khan SN Shaheen F Choudhary MI;Atta-ur-Rahman 《化学与生物多样性》2005,2(4):487-496
A series of 2,4-diaryl-2,3,4,5-tetrahydro- (36-40) and 2,4-diaryl-2,3-dihydro-1,5-benzothiazepines (25-35) have been synthesized from the corresponding chalcones 1-24. Both the benzothiazepines and chalcones were evaluated as DPPH free-radical scavengers and as inhibitors of cholinesterases, urease, and alpha-glucosidase. Compounds 2, 5, 6, 7, 10, 13, 18, 21, 36a, 37a, 37b, and 39a showed significant cholinesterase inhibiting activities. Among the 15 dihydro-1,5-benzothiazepines, 26, 32, and 35 exhibited significant radical-scavenging activities; and six tetrahydro-1,5-benzothiazepines (35, 36a, 36b, 37a, 37b, and 39a) were found to be inhibitors of AChE and BChE. Compounds 22, 25, 26, 33, 35, 36a, 37b, and 39a inhibited urease, and 25 and 27-31 were found to be potent inhibitors of alpha-glucosidase. 相似文献
42.
Purusharth RI Klein F Sulthana S Jäger S Jagannadham MV Evguenieva-Hackenberg E Ray MK Klug G 《The Journal of biological chemistry》2005,280(15):14572-14578
Endoribonuclease E, a key enzyme involved in RNA decay and processing in bacteria, organizes a protein complex called degradosome. In Escherichia coli, Rhodobacter capsulatus, and Streptomyces coelicolor, RNase E interacts with the phosphate-dependent exoribonuclease polynucleotide phosphorylase, DEAD-box helicase(s), and additional factors in an RNA-degrading complex. To characterize the degradosome of the psychrotrophic bacterium Pseudomonas syringae Lz4W, RNase E was enriched by cation exchange chromatography and fractionation in a glycerol density gradient. Most surprisingly, the hydrolytic exoribonuclease RNase R was found to co-purify with RNase E. Co-immunoprecipitation and Ni(2+)-affinity pull-down experiments confirmed the specific interaction between RNase R and RNase E. Additionally, the DEAD-box helicase RhlE was identified as part of this protein complex. Fractions comprising the three proteins showed RNase E and RNase R activity and efficiently degraded a synthetic stem-loop containing RNA in the presence of ATP. The unexpected association of RNase R with RNase E and RhlE in an RNA-degrading complex indicates that the cold-adapted P. syringae has a degradosome of novel structure. The identification of RNase R instead of polynucleotide phosphorylase in this complex underlines the importance of the interaction between endo- and exoribonucleases for the bacterial RNA metabolism. The physical association of RNase E with an exoribonuclease and an RNA helicase apparently is a common theme in the composition of bacterial RNA-degrading complexes. 相似文献
43.
Mutations in TRIOBP, which encodes a putative cytoskeletal-organizing protein, are associated with nonsyndromic recessive deafness
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Riazuddin S Khan SN Ahmed ZM Ghosh M Caution K Nazli S Kabra M Zafar AU Chen K Naz S Antonellis A Pavan WJ Green ED Wilcox ER Friedman PL Morell RJ Riazuddin S Friedman TB 《American journal of human genetics》2006,78(1):137-143
In seven families, six different mutant alleles of TRIOBP on chromosome 22q13 cosegregate with autosomal recessive nonsyndromic deafness. These alleles include four nonsense (Q297X, R788X, R1068X, and R1117X) and two frameshift (D1069fsX1082 and R1078fsX1083) mutations, all located in exon 6 of TRIOBP. There are several alternative splice isoforms of this gene, the longest of which, TRIOBP-6, comprises 23 exons. The linkage interval for the deafness segregating in these families includes DFNB28. Genetic heterogeneity at this locus is suggested by three additional families that show significant evidence of linkage of deafness to markers on chromosome 22q13 but that apparently have no mutations in the TRIOBP gene. 相似文献
44.
Riazuddin S Ahmed ZM Fanning AS Lagziel A Kitajiri S Ramzan K Khan SN Chattaraj P Friedman PL Anderson JM Belyantseva IA Forge A Riazuddin S Friedman TB 《American journal of human genetics》2006,79(6):1040-1051
The inner ear has fluid-filled compartments of different ionic compositions, including the endolymphatic and perilymphatic spaces of the organ of Corti; the separation from one another by epithelial barriers is required for normal hearing. TRIC encodes tricellulin, a recently discovered tight-junction (TJ) protein that contributes to the structure and function of tricellular contacts of neighboring cells in many epithelial tissues. We show that, in humans, four different recessive mutations of TRIC cause nonsyndromic deafness (DFNB49), a surprisingly limited phenotype, given the widespread tissue distribution of tricellulin in epithelial cells. In the inner ear, tricellulin is concentrated at the tricellular TJs in cochlear and vestibular epithelia, including the structurally complex and extensive junctions between supporting and hair cells. We also demonstrate that there are multiple alternatively spliced isoforms of TRIC in various tissues and that mutations of TRIC associated with hearing loss remove all or most of a conserved region in the cytosolic domain that binds to the cytosolic scaffolding protein ZO-1. A wild-type isoform of tricellulin, which lacks this conserved region, is unaffected by the mutant alleles and is hypothesized to be sufficient for structural and functional integrity of epithelial barriers outside the inner ear. 相似文献
45.
Aryl hydrocarbon receptor agonists directly activate estrogen receptor alpha in MCF-7 breast cancer cells 总被引:2,自引:0,他引:2
The aryl hydrocarbon receptor (AhR) binds with high affinity to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related halogenated aromatics, but also binds with lower affinity to structurally diverse exogenous and endogenous chemicals. One study reported that 3-methylcholanthrene (3MC) activated the estrogen receptor (ER) through the AhR, which acts as co-regulatory protein, whereas a recent report showed that 3MC directly bound and activated ERalpha. This study also shows that the AhR agonists benzo[a]pyrene, 3,3',4,4'-tetrachlorobiphenyl, chrysin, 6-methyl-1,3,8-trichlorodibenzofuran, and 3,3'-diindolylmethane also induce ERalpha-dependent transactivation. Moreover, in chromatin immunoprecipitation assays, these compounds induce binding of AhR and ERalpha to the CYP1A1 and pS2 gene promoters, which is consistent with their activities as both selective AhR modulators (SAhRMs) and selective ER modulators (SERMs). 相似文献
46.
Mistry S Rothwell JC Thompson DG Hamdy S 《American journal of physiology. Gastrointestinal and liver physiology》2006,291(4):G666-G671
Human swallowing involves the integration of sensorimotor information with complexities such as taste; however, the interaction between the taste of food and its effects on swallowing control remains unknown. We assessed the effects of pleasant (sweet) and aversive (bitter) tastes on human cortical swallowing motor pathway excitability. Healthy adult male volunteers underwent a transcranial magnetic stimulation (TMS) mapping study (n = 9, mean age: 34 yr) to assess corticobulbar excitability before and up to 60 min after 10-min liquid infusions either 1) as swallowing tasks or 2) delivered directly into the stomach. Infusions were composed of sterile water (neutral), 10% glucose (sweet), and 0.5 mM quinine hydrochloride (bitter). The order of delivery was randomized, and each infusion was given on separate days. Pharyngeal motor-evoked potentials (PMEPs) were recorded from an intraluminal catheter as a measure of corticobulbar excitability and compared using repeated-measures and one-way ANOVA. After the swallowing task (water, glucose, or quinine), repeated-measures ANOVA revealed a significant time interaction across tastants (P = 0.01). One-way ANOVA for each taste showed changes in PMEP amplitudes for both quinine (P = 0.001) and glucose (P = 0.009) solutions but not for water (P = 0.1). Subsequent t-tests showed that glucose and quinine reduced PMEPs by 47% (SD 34) and 37% (SD 54), respectively, at 30 min (P = 0.03). No changes were observed after the infusion of any solution directly into the stomach (P = 0.51). In conclusion, cortical swallowing pathways are similarly modulated by both sweet and bitter tasting stimuli. Changes likely reflect a close interaction between taste and swallowing activity mediated in the central nervous system. 相似文献
47.
Santos RL Hassan MJ Sikandar S Lee K Ali G Martin PE Wambangco MA Ahmad W Leal SM 《Human genetics》2006,120(1):85-92
From a large collection of families with autosomal recessive non-syndromic hearing impairment (NSHI) from Pakistan, linkage has been established for two unrelated consanguineous families to 19p13.2. This new locus was assigned the name DFNB68. A 10 cM genome scan and additional fine mapping were carried out using microsatellite marker loci. Linkage was established for both families to DFNB68 with maximum multipoint LOD scores of 4.8 and 4.6. The overlap of the homozygous regions between the two families was bounded by D19S586 and D19S584, which limits the locus interval to 1.9 cM and contains 1.4 Mb. The genes CTL2, KEAP1 and CDKN2D were screened but were negative for functional sequence variants.Regie Lyn P. Santos and Muhammad Jawad Hassan contributed equally to this work. 相似文献
48.
49.
Ahmed S Adat S Murrells A Owen CP 《Biochemical and biophysical research communications》2002,294(2):380-383
The synthesis, biochemical evaluation and molecular modelling of a series of N-alkylated 4-(4(')-aminobenzyl)-2-oxazolidinones is described involving the derivatisation of the starting R- or S-enantiomer of 4-benzyl-2-oxazolidinones. The compounds were tested for human placental aromatase (AR) inhibition in vitro and were found, in general, to be more potent than the standard compound, aminoglutethimide (AG). The inhibitory activity of the compounds was rationalised through the use of the novel substrate-heme complex (SHC) approach and suggests that the S-enantiomer based compounds protrude beyond the C(13), C(17), and C(16) area of the steroid backbone, resulting in steric hindrance with the active site of AR and thus reduced inhibitory activity. The R-enantiomer based compounds do not protrude in the same area and as such are not thought to undergo any steric hindrance and in comparison to the S-enantiomer, possess greater inhibitory activity. 相似文献
50.
Recently, biosynthesis of metal nanoparticles has drawn considerable attention due to environment-ecofriendly and sustainable methods. Herein, fungus Fusarium solani was selected as candidate for biosynthesis of silver nanoparticles (AgNPs). Factors affecting the biomass concentration, pH of the reaction medium, AgNO(3) concentration and the ratio of AgNO(3) to biomass concentration on the production of AgNPs were extensively studied. Optimum conditions for biosynthesis of AgNPs could be attained using biomass of F. solani (10g/100ml); AgNO(3) (0.078g/100ml); pH, 12; temperature, 25°C and duration, 24h. Under these conditions, the maximum concentration of well stabilized AgNPs obtained was 2000ppm with a mean diameter range of 8-15nm. Such solution is unequivocally feasible for industrial applications. A diluted solution containing 50ppm AgNPs was applied to cotton fabrics which imparts antibacterial activity to the fabric with 97% and 91% reduction of Staphylococcus aureus and Escherichia coli, respectively. 相似文献