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131.
Toxic metal accumulation in soils of agricultural interest is a serious problem needing more attention, and investigations
on soil–plant metal transfer must be pursued to better understand the processes involved in metal uptake. Arbuscular mycorrhizal
(AM) fungi are known to influence metal transfer in plants by increasing plant biomass and reducing metal toxicity to plants
even if diverging results were reported. The effects of five AM fungi isolated from metal contaminated or non-contaminated
soils on metal (Cd, Zn) uptake by plant and transfer to leachates was assessed with Medicago truncatula grown in a multimetallic contaminated agricultural soil. Fungi isolated from metal-contaminated soils were more effective
to reduce shoot Cd concentration. Metal uptake capacity differed between AM fungi and depended on the origin of the isolate.
Not only fungal tolerance and ability to reduce metal concentrations in plant but also interactions with rhizobacteria affected
heavy metal transfer and plant growth. Indeed, thanks to association with nodulating rhizobacteria, one Glomus intraradices inoculum increased particularly plant biomass which allowed exporting twofold more Cd and Zn in shoots as compared to non-mycorrhizal
treatment. Cd concentrations in leachates were variable among fungal treatments, but can be significantly influenced by AM
inoculation. The differential strategies of AM fungal colonisation in metal stress conditions are also discussed. 相似文献
132.
Steven J. Taylor Fariba Soleymanzadeh Anne B. Eldrup Neil A. Farrow Ingo Muegge Alison Kukulka Alisa K. Kabcenell Stephane De Lombaert 《Bioorganic & medicinal chemistry letters》2009,19(20):5864-5868
A series of potent nicotinamide inhibitors of soluble epoxides hydrolase (sEH) is disclosed. This series was designed using structure-based deconstruction and a combination of two HTS hit series, resulting in hybrid analogs that retained the optimal potency from one series, and acceptable in vitro metabolic stability from the other. Structure-guided optimization of these analogs gave rise to nanomolar inhibitors of human sEH that had acceptable plasma exposure to qualify them as probes to determine the in vivo phenotypic consequences of sEH inhibition. 相似文献
133.
Stephane Renaud Philippe Jean-Francois Jean-Claude Anne-Marie Olivier 《Journal of electromyography and kinesiology》2009,19(5):922-930
ObjectiveThe objective of this work was to study modifications in motor control through surface electromyographic (sEMG) activity during a very short all-out cycling exercise.MethodsTwelve male cyclists (age 23 ± 4 years) participated in this study. After a warm-up period, each subject performed three all-out cycling exercises of 6 s separated by 2 min of complete rest. This protocol was repeated three times with a minimum of 2 days between each session. The braking torque imposed on cycling motion was 19 N m. The sEMG of the vastus lateralis was recorded during the first seven contractions of the sprint. Time–frequency analysis of sEMG was performed using continuous wavelet transform. The mean power frequency (MPF, qualitative modifications in the recruitment of motor units) and signal energy (a quantitative indicator of modifications in the motor units recruitment) were computed for the frequency range 10–500 Hz.ResultssEMG energy increased (P ? 0.05) between contraction number 1 and 2, decreased (P ? 0.05) between contraction number 2 and 3 then stabilized between contraction number 3 and 7 during the all-out test. MPF increased (P ? 0.05) during the all-out test. This increase was more marked during the first two contractions.ConclusionsThe decrease in energy and the increase in the sEMG MPF suggest a large spatial recruitment of motor units (MUs) at the beginning of the sprint followed by a preferential recruitment of faster MUs at the end of the sprint, respectively. 相似文献
134.
Magali Lucia Jean-Marc Andre Patrice Gonzalez Magalie Baudrimont Karine Gontier Regine Maury-Brachet Stephane Davail 《Biometals》2009,22(5):843-853
The impact on palmiped Cairina moschata of two levels of dietary cadmium (Cd) contamination (C1: 1 mg kg−1 and C10: 10 mg kg−1) was investigated on liver gene expression by real-time PCR. Genes involved in mitochondrial metabolism, in antioxidant defences,
detoxification and in DNA damage repair were studied. Metallothionein (MT) protein levels and Cd bioaccumulation were also
investigated in liver, kidneys and muscle. Male ducks were subjected to three periods of exposure: 10, 20 and 40 days. Cd
was mainly bioaccumulated in kidneys first and in liver. The concentrations in liver and kidneys appeared to reach a stable
level at 20 days of contamination even if the concentrations in muscle still increased. Cd triggered the enhancement of mitochondrial
metabolism, the establishment of antioxidant defences (superoxide dismutase Mn and Cu/Zn; catalase) and of DNA repair from
20 days of contamination. Discrepancies were observed in liver between MT protein levels and MT gene up-regulation. MT gene
expression appeared to be a late hour biomarker. 相似文献
135.
Rapid high resolution single nucleotide polymorphism-comparative genome hybridization mapping in Caenorhabditis elegans
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We have developed a significantly improved and simplified method for high-resolution mapping of phenotypic traits in Caenorhabditis elegans using a combination of single nucleotide polymorphisms (SNPs) and oligo array comparative genome hybridization (array CGH). We designed a custom oligonucleotide array using a subset of confirmed SNPs between the canonical wild-type Bristol strain N2 and the Hawaiian isolate CB4856, populated with densely overlapping 50-mer probes corresponding to both N2 and CB4856 SNP sequences. Using this method a mutation can be mapped to a resolution of ~200 kb in a single genetic cross. Six mutations representing each of the C. elegans chromosomes were detected unambiguously and at high resolution using genomic DNA from populations derived from as few as 100 homozygous mutant segregants of mutant N2/CB4856 heterozygotes. Our method completely dispenses with the PCR, restriction digest, and gel analysis of standard SNP mapping and should be easy to extend to any organism with interbreeding strains. This method will be particularly powerful when applied to difficult or hard-to-map low-penetrance phenotypes. It should also be possible to map polygenic traits using this method. 相似文献
136.
Pautus S Aboraia AS Bassett CE Brancale A Coogan MP Simons C 《Journal of enzyme inhibition and medicinal chemistry》2009,24(2):487-498
The design of N-phenylbenzo[d]oxazolamines as CYP26A1 inhibitors involved ligand docking experiments using molecular modeling (FlexX) and analysis of ligand interactions at the binding domain. The synthesis of the benzooxazol-2-yl-[phenyl-imidazol-1-yl-methyl)phenyl]amines was achieved by cyclisation of the corresponding isothiocyanates with subsequent introduction of the haem-binding heterocycle. Triazole and tetrazole derivatives were also prepared for comparison with the lead imidazole derivative. The benzooxazol-2-yl-[phenyl-imidazol-1-yl-methyl)phenyl]amines with small substituents in the phenyl ring were moderately potent CYP26A1 inhibitors (IC(50) 8 and 12 microM) and comparable with liarozole (IC(50) 7 microM). 相似文献
137.
138.
Liu BP Cafferty WB Budel SO Strittmatter SM 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2006,361(1473):1593-1610
Robust axonal growth is required during development to establish neuronal connectivity. However, stable fibre patterns are necessary to maintain adult mammalian central nervous system (CNS) function. After adult CNS injury, factors that maintain axonal stability limit the recovery of function. Extracellular molecules play an important role in preserving the stability of the adult CNS axons and in restricting recovery from pathological damage. Adult axonal growth inhibitors include a group of proteins on the oligodendrocyte, Nogo-A, myelin-associated glycoprotein, oligodendrocyte-myelin glycoprotein and ephrin-B3, which interact with axonal receptors, such as NgR1 and EphA4. Extracellular proteoglycans containing chondroitin sulphates also inhibit axonal sprouting in the adult CNS, particularly at the sites of astroglial scar formation. Therapeutic perturbations of these extracellular axonal growth inhibitors and their receptors or signalling mechanisms provide a degree of axonal sprouting and regeneration in the adult CNS. After CNS injury, such interventions support a partial return of neurological function. 相似文献
139.
Multiscale modeling of light absorption in tissues: limitations of classical homogenization approach
In biophotonics, the light absorption in a tissue is usually modeled by the Helmholtz equation with two constant parameters, the scattering coefficient and the absorption coefficient. This classic approximation of "haemoglobin diluted everywhere" (constant absorption coefficient) corresponds to the classical homogenization approach. The paper discusses the limitations of this approach. The scattering coefficient is supposed to be constant (equal to one) while the absorption coefficient is equal to zero everywhere except for a periodic set of thin parallel strips simulating the blood vessels, where it is a large parameter ω. The problem contains two other parameters which are small: ε, the ratio of the distance between the axes of vessels to the characteristic macroscopic size, and δ, the ratio of the thickness of thin vessels and the period. We construct asymptotic expansion in two cases: ε --> 0, ω --> ∞, δ --> 0, ωδ --> ∞, ε2ωδ --> 0 and ε --> 0, ω --> ∞, δ --> 0, ε2ωδ --> ∞, and and prove that in the first case the classical homogenization (averaging) of the differential equation is true while in the second case it is wrong. This result may be applied in the biomedical optics, for instance, in the modeling of the skin and cosmetics. 相似文献
140.