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71.
Nitrogen‐Doped CNx/CNTs Heteroelectrocatalysts for Highly Efficient Dye‐Sensitized Solar Cells 下载免费PDF全文
Aabhash Shrestha Munkhbayar Batmunkh Cameron J. Shearer Yanting Yin Gunther G. Andersson Joseph G. Shapter Shizhang Qiao Sheng Dai 《Liver Transplantation》2017,7(8)
The use of polydopamine as a nitrogen containing precursor to generate catalytically active nitrogen‐doped carbon (CNx) materials on carbon nanotubes (CNTs) is reported. These N‐doped CNx/CNT materials display excellent electrocatalytic activity toward the reduction of triiodide electrolyte in dye‐sensitized solar cells (DSSCs). Further, the influence of various synthesis parameters on the catalytic performance of CNx/CNTs is investigated in detail. The best performing device fabricated with the CNx/CNTs material delivers power conversion efficiency of 7.3%, which is comparable or slightly higher than that of Pt (7.1%) counter electrode‐based DSSC. These CNx/CNTs materials show great potential to address the issues associated with the Pt electrocatalyst including the high cost and scarcity. 相似文献
72.
A new ascomycete species, Jahnula apiospora (Jahnulales, Dothideomycetes), collected from submerged wood in a freshwater creek on Prince Edward Island, Canada, is described
and illustrated. The characteristic features of the new species are globose to subglobose, black, ostiolate, membranous ascomata
with broad, brown, subtending hyphae; a peridial wall composed of an outer layer of thick-walled cells occluded by black,
amorphous material along the upper two-thirds of the ascoma; trabeculate pseudoparaphyses; cylindrical to narrowly fusoid,
fissitunicate asci; and brown, one-septate, apiosporous ascospores without a gelatinous sheath or appendages. 相似文献
73.
Shearer LE 《Indian journal of experimental biology》2008,46(5):384-388
Acupuncture and Qigong are aspects of Chinese medicine, an antique medicine of energy which is thousands of years old. Its primary method of diagnosis is the pulse at the wrist, subtle information accessible to physicians only after years of training. Biophotonics presents the same information visually and makes it available to researchers everywhere, setting in place new experimental protocols for acupuncture and energy medicines. Combining this contemporary tool of technology with principles of the ancient medicine will facilitate in the development of not only medical sciences of energy, but all of the sciences of energy that are coming. 相似文献
74.
Connectivity and resilience of coral reef metapopulations in marine protected areas: matching empirical efforts to predictive needs 总被引:2,自引:1,他引:1
Botsford LW White JW Coffroth MA Paris CB Planes S Shearer TL Thorrold SR Jones GP 《Coral reefs (Online)》2009,28(2):327-337
Design and decision-making for marine protected areas (MPAs) on coral reefs require prediction of MPA effects with population
models. Modeling of MPAs has shown how the persistence of metapopulations in systems of MPAs depends on the size and spacing
of MPAs, and levels of fishing outside the MPAs. However, the pattern of demographic connectivity produced by larval dispersal
is a key uncertainty in those modeling studies. The information required to assess population persistence is a dispersal matrix
containing the fraction of larvae traveling to each location from each location, not just the current number of larvae exchanged
among locations. Recent metapopulation modeling research with hypothetical dispersal matrices has shown how the spatial scale
of dispersal, degree of advection versus diffusion, total larval output, and temporal and spatial variability in dispersal
influence population persistence. Recent empirical studies using population genetics, parentage analysis, and geochemical
and artificial marks in calcified structures have improved the understanding of dispersal. However, many such studies report
current self-recruitment (locally produced settlement/settlement from elsewhere), which is not as directly useful as local
retention (locally produced settlement/total locally released), which is a component of the dispersal matrix. Modeling of
biophysical circulation with larval particle tracking can provide the required elements of dispersal matrices and assess their
sensitivity to flows and larval behavior, but it requires more assumptions than direct empirical methods. To make rapid progress
in understanding the scales and patterns of connectivity, greater communication between empiricists and population modelers
will be needed. Empiricists need to focus more on identifying the characteristics of the dispersal matrix, while population
modelers need to track and assimilate evolving empirical results. 相似文献
75.
Julia E.S. Shearer 《Journal of molecular biology》2009,386(2):316-331
IntI1 mediates the recombination of antibiotic-resistant gene cassettes between different integrons in the same cell, facilitating the persistence and dissemination of these genes. Historically, integrase activity has been measured by conjugating recombinant products from donor cells overexpressing integrase and quantifying them in recipient cells. Here we report the first measurements of the steady-state intracellular abundance of integrase-mediated recombination products in strains expressing natural or high IntI1 levels. Recombination products in both high and natural integrase strains increased markedly through late log phase and continued to rise in stationary phase in the high integrase strain, but declined in the natural expression strain. Simple acquisition of gene cassettes was seen only in strains expressing high integrase; in strains with natural integrase levels, only cointegrates between the two integron-bearing plasmids were detectable at all growth stages. Unexpectedly, more attI × attI than attC × attI recombination products were seen in log phase for both strains; however, in stationary phase, the high integrase strain increased attC recombination, consistent with earlier observations of integrase crossover site preferences. Thus, direct quantification of the steady-state concentration of recombination products reveals that the integrase's intracellular concentration affects the amount and type of recombination events in a growth-phase-dependent manner. 相似文献
76.
Marieke?Pingen Ramin?Sarrami-Forooshani Annemarie?MJ?Wensing Petra?van Ham Agata?Drewniak Charles?AB?Boucher Teunis?BH?GeijtenbeekEmail author Monique?NijhuisEmail author 《Retrovirology》2014,11(1):113
Background
Different patterns of drug resistance are observed in treated and therapy naïve HIV-1 infected populations. Especially the NRTI-related M184I/V variants, which are among the most frequently encountered mutations in treated patients, are underrepresented in the antiretroviral naïve population. M184I/V mutations are known to have a profound effect on viral replication and tend to revert over time in the new host. However it is debated whether a diminished transmission efficacy of HIV variants with a reduced replication capacity can also contribute to the observed discrepancy in genotypic patterns.As dendritic cells (DCs) play a pivotal role in HIV-1 transmission, we used a model containing primary human Langerhans cells (LCs) and DCs to compare the transmission efficacy M184 variants (HIV-M184V/I/T) to HIV wild type (HIV-WT). As control, we used HIV harboring the NNRTI mutation K103N (HIV-K103N) which has a minor effect on replication and is found at a similar prevalence in treated and untreated individuals.Results
In comparison to HIV-WT, the HIV-M184 variants were less efficiently transmitted to CCR5+ Jurkat T cells by both LCs and DCs. The transmission rate of HIV-K103N was slightly reduced to HIV-WT in LCs and even higher than HIV-WT in DCs. Replication experiments in CCR5+ Jurkat T cells revealed no apparent differences in replication capacity between the mutant viruses and HIV-WT. However, viral replication in LCs and DCs was in concordance with the transmission results; replication by the HIV-M184 variants was lower than replication by HIV-WT, and the level of replication of HIV-K103N was intermediate for LCs and higher than HIV-WT for DCs.Conclusions
Our data demonstrate that drug resistant M184-variants display a reduced replication capacity in LCs and DCs which directly impairs their transmission efficacy. As such, diminished transmission efficacy may contribute to the lower prevalence of drug resistant variants in therapy naive individuals.77.
John W. Newman Theresa L. Pedersen Verdayne R. Brandenburg William S. Harris Gregory C. Shearer 《PloS one》2014,9(11)
Background
Oxylipins mediate inflammation, vascular tension, and more. Their presence in lipoproteins could explain why lipoproteins mediate nearly identical activities.Methods
To determine how oxylipins are distributed in the lipoproteins of hypertriglyceridemic subjects, and whether omega-3 fatty acids alter them in a manner consistent with improved cardiovascular health, we recruited 15 dyslipidemic subjects whose levels of low density lipoprotein cholesterol (LDL-C) were at goal but who remained hypertriglyceridemic (200–499 mg/dL). They were treated them with the indicated dose of 4 g/d omega-3 acid ethyl esters (P-OM3) for 8 weeks. Measured oxylipins included mid-chain alcohols (HETEs, HEPEs and HDoHEs), ketones (KETEs), epoxides (as EpETrEs, EpETEs, and EpDPEs).Results
At baseline, arachidonate-oxylipins (HETEs, KETEs, and EpETrEs) were most abundant in plasma with the greatest fraction of total abundance (mean |95% CI|) being carried in high density lipoproteins (HDL); 42% |31, 57| followed by very low density lipoproteins (VLDL); 27% |20, 36|; and LDL 21% |16, 28|. EPA- and DHA-derived oxylipins constituted less than 11% of total. HDL carried alcohols and epoxides but VLDL was also rich in ketones. Treatment decreased AA-derived oxylipins across lipoprotein classes (−23% |−33, −12|, p = 0.0003), and expanded EPA−(322% |241, 422|, p<0.0001) and DHA-derived oxylipins (123% |80, 176|, p<0.0001).Conclusions
Each lipoprotein class carries a unique oxylipin complement. P-OM3 treatment alters the oxylipin content of all classes, reducing pro-inflammatory and increasing anti-inflammatory species, consistent with the improved inflammatory and vascular status associated with the treatment.Trial Registration
ClinicalTrials.gov NCT00959842相似文献78.
Marie S. A. Palmn?s Theresa E. Cowan Marc R. Bomhof Juliet Su Raylene A. Reimer Hans J. Vogel Dustin S. Hittel Jane Shearer 《PloS one》2014,9(10)
Aspartame consumption is implicated in the development of obesity and metabolic disease despite the intention of limiting caloric intake. The mechanisms responsible for this association remain unclear, but may involve circulating metabolites and the gut microbiota. Aims were to examine the impact of chronic low-dose aspartame consumption on anthropometric, metabolic and microbial parameters in a diet-induced obese model. Male Sprague-Dawley rats were randomized into a standard chow diet (CH, 12% kcal fat) or high fat (HF, 60% kcal fat) and further into ad libitum water control (W) or low-dose aspartame (A, 5–7 mg/kg/d in drinking water) treatments for 8 week (n = 10–12 animals/treatment). Animals on aspartame consumed fewer calories, gained less weight and had a more favorable body composition when challenged with HF compared to animals consuming water. Despite this, aspartame elevated fasting glucose levels and an insulin tolerance test showed aspartame to impair insulin-stimulated glucose disposal in both CH and HF, independently of body composition. Fecal analysis of gut bacterial composition showed aspartame to increase total bacteria, the abundance of Enterobacteriaceae and Clostridium leptum. An interaction between HF and aspartame was also observed for Roseburia ssp wherein HF-A was higher than HF-W (P<0.05). Within HF, aspartame attenuated the typical HF-induced increase in the Firmicutes:Bacteroidetes ratio. Serum metabolomics analysis revealed aspartame to be rapidly metabolized and to be associated with elevations in the short chain fatty acid propionate, a bacterial end product and highly gluconeogenic substrate, potentially explaining its negative affects on insulin tolerance. How aspartame influences gut microbial composition and the implications of these changes on the development of metabolic disease require further investigation. 相似文献
79.
Olga V. Savinova Kristi Fillaus Linhong Jing William S. Harris Gregory C. Shearer 《PloS one》2014,9(8)
Objective
The purpose of this study was to compare the apolipoprotein composition of the three major lipoprotein classes in patients with metabolic syndrome to healthy controls.Methods
Very low density (VLDL), intermediate/low density (IDL/LDL, hereafter LDL), and high density lipoproteins (HDL) fractions were isolated from plasma of 56 metabolic syndrome subjects and from 14 age-sex matched healthy volunteers. The apolipoprotein content of fractions was analyzed by one-dimensional (1D) gel electrophoresis with confirmation by a combination of mass spectrometry and biochemical assays.Results
Metabolic syndrome patients differed from healthy controls in the following ways: (1) total plasma - apoA1 was lower, whereas apoB, apoC2, apoC3, and apoE were higher; (2) VLDL - apoB, apoC3, and apoE were increased; (3) LDL - apoC3 was increased, (4) HDL -associated constitutive serum amyloid A protein (SAA4) was reduced (p<0.05 vs. controls for all). In patients with metabolic syndrome, the most extensively glycosylated (di-sialylated) isoform of apoC3 was reduced in VLDL, LDL, and HDL fractions by 17%, 30%, and 25%, respectively (p<0.01 vs. controls for all). Similarly, the glycosylated isoform of apoE was reduced in VLDL, LDL, and HDL fractions by 15%, 26%, and 37% (p<0.01 vs. controls for all). Finally, glycosylated isoform of SAA4 in HDL fraction was 42% lower in patients with metabolic syndrome compared with controls (p<0.001).Conclusions
Patients with metabolic syndrome displayed several changes in plasma apolipoprotein composition consistent with hypertriglyceridemia and low HDL cholesterol levels. Reduced glycosylation of apoC3, apoE and SAA4 are novel findings, the pathophysiological consequences of which remain to be determined. 相似文献80.
In contrast to other fat-soluble vitamins, dietary vitamin K is rapidly lost to the body resulting in comparatively low tissue stores. Deficiency is kept at bay by the ubiquity of vitamin K in the diet, synthesis by gut microflora in some species, and relatively low vitamin K cofactor requirements for γ-glutamyl carboxylation. However, as shown by fatal neonatal bleeding in mice that lack vitamin K epoxide reductase (VKOR), the low requirements are dependent on the ability of animals to regenerate vitamin K from its epoxide metabolite via the vitamin K cycle. The identification of the genes encoding VKOR and its paralog VKOR-like 1 (VKORL1) has accelerated understanding of the enzymology of this salvage pathway. In parallel, a novel human enzyme that participates in the cellular conversion of phylloquinone to menaquinone (MK)-4 was identified as UbiA prenyltransferase-containing domain 1 (UBIAD1). Recent studies suggest that side-chain cleavage of oral phylloquinone occurs in the intestine, and that menadione is a circulating precursor of tissue MK-4. The mechanisms and functions of vitamin K recycling and MK-4 synthesis have dominated advances made in vitamin K biochemistry over the last five years and, after a brief overview of general metabolism, are the main focuses of this review. 相似文献