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81.
Wee Ling Heng Chong Hee Lim Ban Hock Tan Maciej Piotr Chlebicki Winnie Hui Ling Lee Tracy Seck Yeong Phang Lim 《PloS one》2012,7(12)
Background
In February 2012, the National Cardiovascular Homograft Bank (NCHB) became the first tissue bank outside of North America to receive accreditation from the American Association of Tissue Banks. From 2008 to 2009, NCHB had been decontaminating its cardiovascular homografts with penicillin and streptomycin. The antibiotic decontamination protocol was changed in January 2010 as amikacin and vancomycin were recommended, in order to cover bacteria isolated from post-recovery and post- antibiotic incubation tissue cultures.Aim
The objective of this study is to determine the optimal incubation conditions for decontamination of homografts by evaluating the potencies of amikacin and vancomycin in different incubation conditions. Retrospective reviews of microbiological results were also performed for homografts recovered from 2008 to 2012, to compare the effectiveness of penicillin-streptomycin versus the amikacin-vancomycin regimens.Methods
Based on microbiological assays stated in United States Pharmacopeia 31, potency of amikacin was evaluated by turbidimetric assay using Staphylococcus aureus, while vancomycin was by diffusion assay using Bacillus subtilis sporulate. Experiments were performed to investigate the potencies of individual antibiotic 6-hours post incubation at 4°C and 37°C and 4°C for 24 hours, after the results suggested that amikacin was more potent at lower temperature.Findings
Tissue incubation at 4°C for 24 hours is optimal for both antibiotics, especially for amikacin, as its potency falls drastically at 37°C.Conclusion
The decontamination regimen of amikacin-vancomycin at 4°C for 24 hours is effective. Nevertheless, it is imperative to monitor microbiological trends closely and evaluate the efficacy of current antibiotics regimen against emerging strains of micro-organisms. 相似文献82.
83.
Kumar P Ban HS Kim SS Wu H Pearson T Greiner DL Laouar A Yao J Haridas V Habiro K Yang YG Jeong JH Lee KY Kim YH Kim SW Peipp M Fey GH Manjunath N Shultz LD Lee SK Shankar P 《Cell》2008,134(4):577-586
Evaluation of the therapeutic potential of RNAi for HIV infection has been hampered by the challenges of siRNA delivery and lack of suitable animal models. Using a delivery method for T cells, we show that siRNA treatment can dramatically suppress HIV infection. A CD7-specific single-chain antibody was conjugated to oligo-9-arginine peptide (scFvCD7-9R) for T cell-specific siRNA delivery in NOD/SCIDIL2rgamma-/- mice reconstituted with human lymphocytes (Hu-PBL) or CD34+ hematopoietic stem cells (Hu-HSC). In HIV-infected Hu-PBL mice, treatment with anti-CCR5 (viral coreceptor) and antiviral siRNAs complexed to scFvCD7-9R controlled viral replication and prevented the disease-associated CD4 T cell loss. This treatment also suppressed endogenous virus and restored CD4 T cell counts in mice reconstituted with HIV+ peripheral blood mononuclear cells. Moreover, scFvCD7-9R could deliver antiviral siRNAs to naive T cells in Hu-HSC mice and effectively suppress viremia in infected mice. Thus, siRNA therapy for HIV infection appears to be feasible in a preclinical animal model. 相似文献
84.
Ankyrin repeat proteins (ARPs) appear to be abundant in organisms from all phyla, and play critical regulatory roles, mediating
specific interactions with target biomolecules and thus ordering the sequence of events in diverse cellular processes. ARPs
possess a non-globular scaffold consisting of repeating motifs named ankyrin (ANK) repeats, which stack on each other. The
modular architecture of ARPs provides a new paradigm for understanding protein stability and folding mechanisms. In the present
study, the stability of various C-terminal fragments of the ARP p18INK4c was investigated by all-atomic 450 ns molecular dynamics (MD) simulations in explicit water solvent. Only motifs with at
least two ANK repeats made stable systems in the available timescale. All smaller fragments were unstable, readily losing
their native fold and α-helical content. Since each non-terminal ANK repeat has two hydrophobic sides, we may hypothesize
that at least one hydrophobic side must be fully covered and shielded from the water as a necessary, but not sufficient, condition
to maintain ANK repeat stability. Consequently, at least two ANK repeats are required to make a stable ARP.
Figure Structure of the p18INK4c protein (PDB entry 1IHB, chain B), which is a member of the cyclin-dependent kinase inhibitor (INK)
tumor suppressor family with five ankyrin (ANK) repeat modules. The figure was generated by PyMol
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
85.
The folding of aptamer immobilized on an Au electrode was successfully detected using label-free electrochemical methods. A thrombin binding DNA aptamer was used as a model system in the presence of various monovalent cations. Impedance spectra showed that the extent to which monovalent cations assist in folding of aptamer is ordered as K(+) > NH(4)(+) > Na(+) > Cs(+). Our XPS analysis also showed that K(+) and NH(4)(+) caused a conformational change of the aptamer in which it forms a stable complex with these monovalent ions. Impedance results for the interaction between aptamer and thrombin indicated that thrombin interacts more with folded aptamer than with unfolded aptamer. The EQCM technique provided a quantitative analysis of these results. In particular, the present impedance results showed that thrombin participates a folding of aptamer to some extent, and XPS analysis confirmed that thrombin stabilizes and induces the folding of aptamer. 相似文献
86.
Rutkowska A Mayer MP Hoffmann A Merz F Zachmann-Brand B Schaffitzel C Ban N Deuerling E Bukau B 《The Journal of biological chemistry》2008,283(7):4124-4132
In all organisms ribosome-associated chaperones assist early steps of protein folding. To elucidate the mechanism of their action, we determined the kinetics of individual steps of the ribosome binding/release cycle of bacterial trigger factor (TF), using fluorescently labeled chaperone and ribosome-nascent chain complexes. Both the association and dissociation rates of TF-ribosome complexes are modulated by nascent chains, whereby their length, sequence, and folding status are influencing parameters. However, the effect of the folding status is modest, indicating that TF can bind small globular domains and accommodate them within its substrate binding cavity. In general, the presence of a nascent chain causes an up to 9-fold increase in the rate of TF association, which provides a kinetic explanation for the observed ability of TF to efficiently compete with other cytosolic chaperones for binding to nascent chains. Furthermore, a subset of longer nascent polypeptides promotes the stabilization of TF-ribosome complexes, which increases the half-life of these complexes from 15 to 50 s. Nascent chains thus regulate their folding environment generated by ribosome-associated chaperones. 相似文献
87.
Toyoda T Tsukamoto T Hirano N Mizoshita T Kato S Takasu S Ban H Tatematsu M 《Histology and histopathology》2008,23(5):593-599
88.
A pyramided FHB resistance line of wheat (WSY) was previously developed from three FHB resistant cultivars (Sumai 3, Wangshuibai,
and Nobeokabouzu) in the Jiangsu Academy of Agricultural Sciences, China. In the present study, we analyzed the genetic relationship
between WSY and the three parental cultivars using DNA markers in order to clarify how many and which resistance genes had
accumulated in WSY. We analyzed 282 DNA markers from the 21 wheat chromosomes. WSY was found to include different chromosome
regions that harbored putative FHB QTLs of the three parental germplasm. Haplotypes of DNA markers on these QTL regions revealed
that the 1BL, 2BL, 5AS, and 7AL QTL regions were from Sumai 3, the 2AS, 2DS, 3AS, and 6BS QTL regions were from Wangshuibai,
and the 3BS QTL region was from Nobeokabouzu. This study showed that different resistance genes from the different resistant
germplasm had indeed accumulated in WSY. WSY is a potential resistant resource for FHB resistance in wheat breeding programs. 相似文献
89.
Cultivated plant species diversity in home gardens of an Amazonian peasant village in Northeastern Peru 总被引:1,自引:0,他引:1
Research on agrobiodiversity points to the importance of home gardens in situ conservation, yet few studies to date explicate
the origins and dynamics of plant species diversity. In this paper, we examine inter-household variations in cultivated plant
species diversity among house gardens in a traditional peasant community, near Iquitos, Peru. In-depth household interviews
(n = 24) and garden/field surveys reveal that home gardens are clearly the site of highest plant diversity in farmers’ field
portfolios, and that substantial differences exist in garden composition, plant diversity, and the sources of garden planting
material across households. Statistical analyses indicate that home garden diversity is related strongly to specific garden
characteristics, household socioeconomic features, and access to planting material including seeds, cuttings, and suckers.
The role and implications of differential access to planting material in the development and maintenance of crop species diversity
is signaled as an important theme for future study in economic botany. 相似文献