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81.
82.
Heterogeneity in host susceptibility and transmissibility to parasite attack allows a lower transmission rate to sustain an epidemic than is required in homogeneous host populations. However, this heterogeneity can leave some hosts with little susceptibility to disease, and at high transmission rates, epidemic size can be smaller than for diseases where the host population is homogeneous. In a heterogeneous host population, we model natural selection in a parasite population where host heterogeneity is exploited by different strains to varying degrees. This partitioning of the host population allows coexistence of competing parasite strains, with the heterogeneity-exploiting strains infecting the more susceptible hosts, in the absence of physiological tradeoffs and spatial heterogeneity, and even for markedly different transmission rates. In our model, intermediate-strategy parasites were selected against: should coexistence occur, an equilibrium is reached where strains occupied only the extreme ends of trait space, under appropriate conditions selecting for lower R0 . 相似文献
83.
Pacher Pal Kecskemeti Valeria Ronai Andras Z. Balogh Istvan Gabor Gabor Matkovics Bela 《Molecular and cellular biochemistry》1998,187(1-2):183-190
Human placental syncytiotrophoblast basal membrane plays an important role in transfer of nutrients from the mother to the growing fetus all throughout gestation. The membrane lipid composition together with the bilayer fluidity is found to be the major index in modulation of these transport processes. In the present study, the effects of changing lipid composition on the placental basal membrane fluidity and the modulating influence of the latter on membrane enzyme and transport functions with progress of gestation,were investigated. Steady-state fluorescence analysis using 1,6-diphenyl-1,3,5 hexatriene as the probe, indicated a decrease in fluorescence anisotropy of both labeled native membrane vesicles and liposomes prepared from lipids extracted from the basal membrane vesicles, signifying increased bilayer fluidity with progress of gestation. This in turn, was successfully correlated to the lowering of cholesterol content and enhanced phospholipid concentration with a steady decrease in cholesterol/phospholipid ratio during placental development. Enhanced Na+-K+-ATPase activity and steady-state glucose uptake across basal membrane with gestational progress suggested modulation of membrane protein functions by the fluidity, which was further corroborated by the increased bilayer fluidity and enzyme activity in benzyl alcohol treated basal membrane in each gestational age group. 相似文献
84.
Frequent genes in rare diseases: panel‐based next generation sequencing to disclose causal mutations in hereditary neuropathies 下载免费PDF全文
Maike F. Dohrn Nicola Glöckle Lejla Mulahasanovic Corina Heller Julia Mohr Christine Bauer Erik Riesch Andrea Becker Florian Battke Konstanze Hörtnagel Thorsten Hornemann Saranya Suriyanarayanan Markus Blankenburg Jörg B. Schulz Kristl G. Claeys Burkhard Gess Istvan Katona Andreas Ferbert Debora Vittore Alexander Grimm Stefan Wolking Ludger Schöls Holger Lerche G. Christoph Korenke Dirk Fischer Bertold Schrank Urania Kotzaeridou Gerhard Kurlemann Bianca Dräger Anja Schirmacher Peter Young Beate Schlotter‐Weigel Saskia Biskup 《Journal of neurochemistry》2017,143(5):507-522
85.
Khairul A. Kamaruzaman Peter M. Moyle Istvan Toth 《International journal of peptide research and therapeutics》2017,23(1):119-134
Gene therapy is a promising means to treat or prevent diseases either through gene silencing or expression. Some of the most effective delivery agents are polycationic dendrimers, which are highly branched constructs incorporating many positively charged groups. Two of the most effective dendrimers are polyethyleneimine (PEI) and poly(amidoamine) (PAMAM), which show high proficiency at overcoming barriers to oligonucleotide delivery. However, because of their abundance of cationic charge, they are associated with severe toxicity. We have therefore aimed to develop a low toxicity oligonucleotide delivery system, incorporating multiple components that have been selected and optimised to overcome the barriers to efficient oligonucleotide delivery. In this work we have focused on improving the toxicity, cellular uptake, and condensation of plasmid DNA (pDNA) through the fusion of synthetic poly-l-lysine (PLL) dendrons with the cell penetrating peptide TAT(48-60). A library of dendron structures, from 4+ to 16+ charge, and constructs containing six histidine residues, were synthesised. The effects of each modification on pDNA binding and condensation; cellular uptake and toxicity; and the size and zeta-potential of the complexes were assessed to identify the optimum dendron for incorporation into our systems. This work concluded that increasing the dendron charge from 4+ to 16+ significantly improved cellular uptake and pDNA condensation, with no effect on toxicity, while PLL dendrons with greater than 16+ charge could not be efficiently produced. In comparison, the incorporation of six histidines into these constructs had a variable effect on cellular uptake, and generated larger sized complexes, but did not affect toxicity. 相似文献
86.
Biochemical assay-based selectivity profiling of clinically relevant kinase inhibitors on mutant forms of EGF receptor 总被引:1,自引:0,他引:1
Varkondi E Pinter F Robert K Schwab R Breza N Orfi L Keri G Petak I 《Journal of receptor and signal transduction research》2008,28(3):295-306
Gefitinib and erlotinib are potent EGFR tyrosine kinase inhibitors (potentially) useful for the treatment of non-small-cell lung cancer (NSCLC). Clinical responses, however, in NSCLC patients have been linked to the presence of certain activating mutations of EGFR. We used an ELISA-based biochemical assay to confirm the selective inhibitory efficacy of gefitinib and erlotinib on the activated mutant receptor. Our results are in line with the clinical observations providing evidence for the predictive power of the kinase assay. Four additional compounds were also investigated: CI-1033 and EKB-569 had dramatic inhibitory effects on all EGFR forms, whereas PD153035 and AG1478 were active on wild-type and activating mutant protein. In docking simulations with wild-type EGFR, our inhibitory data are in good agreement with the binding scores. These data confirm that anilinoquinazolines are good starting structures for the next generation of selective drugs against mutant EGFR, whereas CI-1033 and EKB-569 may represent advances for patients with both wild-type and anilinoquinazoline-resistant mutant tumors. 相似文献
87.
MOTIVATION: High-throughput 'ChIP-chip' and 'ChIP-seq' methodologies generate sufficiently large data sets that analysis poses significant informatics challenges, particularly for research groups with modest computational support. To address this challenge, we devised a software platform for storing, analyzing and visualizing high resolution genome-wide binding data. GeneTrack automates several steps of a typical data processing pipeline, including smoothing and peak detection, and facilitates dissemination of the results via the web. Our software is freely available via the Google Project Hosting environment at http://genetrack.googlecode.com 相似文献
88.
The opioid receptor system in the central nervous system controls a number of physiological processes, most notably pain. However, most opioids currently available have a variety of side-effects as well as exhibiting tolerance. Tolerance is most likely to be a complex phenomenon, however, the role of receptor internalisation is thought to play a crucial role. In this study, we examined the role of aromaticity in ligand-mediated receptor internalisation of the mu-opioid receptor (MOPR). These studies show that the amount of receptor internalisation may be dependant on the amphiphilicity of the ligand. Specifically, deletion of the C-terminus aromatic residues of endomorphin 1, particularly tryptophan reduces receptor-mediated internalisation whilst the addition of tryptophan within the enkephalin sequence increases receptor internalisation and decreases tolerance. 相似文献
89.
Fujita Y Abdel-Aal AB Wimmer N Batzloff MR Good MF Toth I 《Bioorganic & medicinal chemistry》2008,16(19):8907-8913
Synthesis of four glycolipids with different number of lauroyl groups on glucose or cellobiose as scaffolds is described. Their immunological evaluations either admixed with or covalently linked to J8, a peptide antigen derived from the C-terminus of the antiphagocytic M-protein of group A streptococcus, are also investigated. Administration of mixtures of J8 and glycolipids to B10BR (H-2(k)) mice induced low-levels of J8-specific IgG antibodies. While glycolipopeptides, in which J8 was covalently linked to the synthetic glycolipids, demonstrated high-levels of antibody titers comparable with the co-administration of these glycolipopeptides with complete Freund's adjuvant, suggesting clearly the strong potency of the synthesized glycolipids as self-adjuvanting moieties. 相似文献
90.
Christian Cortés-Rojo Elizabeth Calderón-Cortés Mónica Clemente-Guerrero Mirella Estrada-Villagómez Salvador Manzo-Avalos Ricardo Mejía-Zepeda Istvan Boldogh Alfredo Saavedra-Molina 《Journal of bioenergetics and biomembranes》2009,41(1):15-28
Lipoperoxidative damage to the respiratory chain proteins may account for disruption in mitochondrial electron transport chain
(ETC) function and could lead to an augment in the production of reactive oxygen species (ROS). To test this hypothesis, we
investigated the effects of lipoperoxidation on ETC function and cytochromes spectra of Saccharomyces cerevisiae mitochondria. We compared the effects of Fe2+ treatment on mitochondria isolated from yeast with native (lipoperoxidation-resistant) and modified (lipoperoxidation-sensitive)
fatty acid composition. Augmented sensitivity to oxidative stress was observed in the complex III-complex IV segment of the
ETC. Lipoperoxidation did not alter the cytochromes content. Under lipoperoxidative conditions, cytochrome c reduction by succinate was almost totally eliminated by superoxide dismutase and stigmatellin. Our results suggest that lipoperoxidation
impairs electron transfer mainly at cytochrome b in complex III, which leads to increased resistance to antimycin A and ROS generation due to an electron leak at the level
of the QO site of complex III. 相似文献