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71.
Semliki Forest virus was grown in BHK cells and labeled in vivo with radio-active monosaccharides. promnase digenst of the virus chromatographer on Bio-Gel P 6 revealed glycopeptides of A-type and B-type. (For the nomenclature see Johnson J. and Clamp J.R. (1971) Biochem. J. 123, 739–745) The former was labeled with [3H]fucose, [3H]galactose, [3H]mannose and [14C]glucosamine, the latter only with [3H]mannose and [14C]glucosamine. The three envelope glycoproteins E1, E2 and E3 were isolated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and subjected to pronase digestion. The glycoproteins E1 and E3 revealed glycopeptides of A-type. E2 revealed glycopeptides of B-type. E2 yielded additionally a glycopeptide (Mr3100) which was heavily labeled from [3H]galactose, but only marginally from [14C]glucosamine, [3H]fucose and [3H]mannose. Wether this glycopeptide belongs to the A-type or not remains uncertain. The apparent molecular weights of the A-type units measured by gel filtration were 3400 in E1 and 4000 in E3; the B-type unit of E2 had an apparent molecular weight of 2000. Combined with the findings of our earlier chemical analysis these data suggast that E1 and E3 contain on the average one A-type unit; E2 probably contains one 3100 dalton unit plus one or two B-type units. 相似文献
72.
Radiostereometric analysis (RSA) has become one of the recommended techniques for pre-market evaluation of new joint implant designs. In this study we evaluated the effect of repositioning of X-ray tubes and phantom model on the precision of the RSA method. In precision measurements, we utilized mean error of rigid body fitting (ME) values as an internal control for examinations. ME value characterizes relative motion among the markers within each rigid body and is conventionally used to detect loosening of a bone marker. Three experiments, each consisting of 10 double examinations, were performed. In the first experiment, the X-ray tubes and the phantom model were not repositioned between one double examination. In experiments two and three, the X-ray tubes were repositioned between one double examination. In addition, the position of the phantom model was changed in experiment three. Results showed that significant differences could be found in 2 of 12 comparisons when evaluating the translation and rotation of the prosthetic components. Repositioning procedures increased ME values mimicking deformation of rigid body segments. Thus, ME value seemed to be a more sensitive parameter than migration values in this study design. These results confirmed the importance of standardized radiographic technique and accurate patient positioning for RSA measurements. Standardization and calibration procedures should be performed with phantom models in order to avoid unnecessary radiation dose of the patients. The present model gives the means to establish and to follow the intra-laboratory precision of the RSA method. The model is easily applicable in any research unit and allows the comparison of the precision values in different laboratories of multi-center trials. 相似文献
73.
Periodontal infections and atherosclerosis: mere associations? 总被引:5,自引:0,他引:5
PURPOSE OF REVIEW: Several lines of evidence from the last few decades suggest that periodontitis is an important risk factor for cardiovascular diseases. In this review we discuss the recent findings on the systemic effects of periodontitis, which may contribute to the pathogenesis of atherosclerosis, with a special emphasis on lipoproteins. RECENT FINDINGS: In addition to the epidemiological studies exploring the direct or indirect relationship between clinical periodontitis and cardiovascular diseases, studies utilizing serology, animal models, cell cultures, and biochemistry of lipoproteins have been published. Local infection in the periodontal pockets triggers a systemic inflammatory response releasing inflammatory mediators and awakens a strong immune response against periodontal pathogens. Elevated systemic antibody levels especially to Porphyromonas gingivalis are associated with an increased risk for atherosclerosis. Periodontitis is also accompanied by proatherogenic changes in both low and high density lipoproteins, which lead to enhanced cholesteryl ester uptake by and reduced cholesterol efflux from macrophages. Vesicles and lipopolysaccharide isolated from P. gingivalis activate macrophages to convert into foam cells. Moreover, animal studies have demonstrated that infection by P. gingivalis enhances progression of atherosclerosis. SUMMARY: Recent studies have clarified the mechanisms by which periodontitis may contribute to the development of atherosclerosis. Serological, animal, and cell culture studies provide evidence that infection by P. gingivalis may promote atherosclerosis. The influence of periodontitis on lipoprotein metabolism has emerged as a new, important factor. Recent studies provide experimental proof that periodontitis may predispose to atherosclerosis. 相似文献
74.
Pussinen PJ Jauhiainen M Vilkuna-Rautiainen T Sundvall J Vesanen M Mattila K Palosuo T Alfthan G Asikainen S 《Journal of lipid research》2004,45(1):139-147
Periodontitis, a consequence of persistent bacterial infection and chronic inflammation, has been suggested to predict coronary heart disease (CHD). The aim of this study was to investigate the impact of periodontitis on HDL structure and antiatherogenic function in cholesterol efflux in vitro. HDL was isolated from 30 patients (age 43.6 +/- 6.1 years, mean +/- SD) with periodontitis before and after (3.2 +/- 1.4 months) periodontal treatment. The capacity of HDL for cholesterol efflux from macrophages (RAW 264.7), HDL composition, and key proteins of HDL metabolism were determined. After periodontal treatment, phospholipid transfer protein (PLTP) activity was 6.2% (P<0.05) lower, and serum HDL cholesterol concentration, PLTP mass, and cholesteryl ester transfer protein activity were 10.7% (P<0.001), 7.1% (P=0.078), and 19.4% (P<0.001) higher, respectively. The mean HDL2/HDL3 ratio increased from 2.16 +/- 0.87 to 3.56 +/- 0.48 (P<0.05). HDL total phospholipid mass and sphingomyelin-phosphatidylcholine ratio were 7.4% (P<0.05) and 36.8% (P<0.001) higher, respectively. The HDL-mediated cholesterol efflux tended to be higher after periodontal treatment; interestingly, this increase was significant (P<0.05) among patients whose C-reactive protein decreased (53.7% reduction, P=0.015) and who were positive by PCR for Actinobacillus actinomycetemcomitans. These results suggest that periodontitis causes similar, but milder, changes in HDL metabolism than those that occur during the acute-phase response and that periodontitis may diminish the antiatherogenic potency of HDL, thus increasing the risk for CHD. 相似文献
75.
Functional expression of Escherichia coli enzymes synthesizing GDP-L-fucose from inherent GDP-D-mannose in Saccharomyces cerevisiae 总被引:1,自引:0,他引:1
Fucosylation of glycans on glycoproteins and -lipids requires the enzymatic activity of relevant fucosyltransferases and GDP-L-fucose as the donor. Due to the biological importance of fucosylated glycans, a readily accessible source of GDP-L-fucose would be required. Here we describe the construction of a stable recombinant S.cerevisiae strain expressing the E.coli genes gmd and wcaG encoding the two enzymes, GDP-mannose-4,6-dehydratase (GMD) and GDP-4-keto-6-deoxy-D-mannose-3,5-epimerase/4-reductase (GMER(FX)) respectively, needed to convert GDP-mannose to GDP-fucose via the de novo pathway. Taking advantage of the rich inherent cytosolic GDP-mannose pool in S.cerevisiae cells we could easily produce 0.2 mg/l of GDP-L-fucose with this recombinant yeast strain without addition of any external GDP-mannose. The GDP-L-fucose product could be used as the fucose donor for alpha1,3fucosyltransferase to synthesize sialyl Lewis x (sLex), a glycan crucial for the selectin-dependent leukocyte traffic. 相似文献
76.
Mattila PE Green CE Schaff U Simon SI Walcheck B 《American journal of physiology. Cell physiology》2005,289(2):C323-C332
L-selectin (CD62L) amplifies neutrophil capture within the microvasculature at sites of inflammation. Activation by G protein-coupled stimuli or through ligation of L-selectin promotes clustering of L-selectin and serves to increase its adhesiveness, signaling, and colocalization with 2-integrins. Currently, little is known about the molecular process regulating the lateral mobility of L-selectin. On neutrophil stimulation, a progressive change takes place in the organization of its plasma membrane, resulting in membrane domains that are characteristically enriched in glycosyl phosphatidylinositol (GPI)-anchored proteins and exclude the transmembrane protein CD45. Clustering of L-selectin, facilitated by E-selectin engagement or antibody cross-linking, resulted in its colocalization with GPI-anchored CD55, but not with CD45 or CD11c. Disrupting microfilaments in neutrophils or removing a conserved cationic motif in the cytoplasmic domain of L-selectin increased its mobility and membrane domain localization in the plasma membrane. In addition, the conserved element was critical for L-selectin-dependent tethering under shear flow. Our data indicate that L-selectins lateral mobility is regulated by interactions with the actin cytoskeleton that in turn fortifies leukocyte tethering. We hypothesize that both membrane mobility and stabilization augment L-selectins effector functions and are regulated by dynamic associations with membrane domains and the actin cytoskeleton. membrane domains; adhesion; leukocyte; inflammation 相似文献
77.
Two rapid and simple procedures for the quantitative analysis of GDP-l-fucose (GDP-Fuc) are described. The methods are based on time-resolved fluorescence and microplate assay technology. The first assay relies on measuring the enzyme activity of alpha1, 3-fucosyltransferase. In this assay, transfer of fucose from GDP-Fuc converts sialyllactosamine to sialyl Lewis x tetrasaccharide, which is detected and quantified by relevant antibodies on a microplate. The formation of the reaction product is directly dependent on the presence of GDP-Fuc in the concentration range of 10-10,000 nM. In the second method GDP-Fuc inhibits the binding of fucose-specific Aleuria aurantia lectin to fucosylated glycan on a microwell. The lectin-based assay is less sensitive than the enzyme assay, but it is cheaper and faster. We used these assays in monitoring the amount of GDP-Fuc in crude lysates of transgenic yeast, which expresses the enzymes producing GDP-Fuc. The newly developed assays are versatile and applicable to measure also other nucleotide sugars or glycosyltransferase activities in a high-throughput manner. 相似文献
78.
Twelve healthy subjects ingested temazepam 20 mg in two different formulations (soft gelatine capsule or uncoated tablet) and matched placebo at one-week intervals in double-blind and cross-over conditions. Venous blood was sampled before the drug intake and 0.5, 1, 2, 3, 8, 12, and 24 hours after it, and plasma temazepam concentrations were assayed by gas chromatography. Psychomotor performance was measured objectively (digit symbol substitution, letter cancellation, Maddox wing) and subjectively (visual analogue scales) before the drug intake and 1, 2, and 3 hours after it. Peak concentrations of plasma temazepam were reached at about one hour, and they were higher after the capsule than after the tablet (mean values 750 vs. 587 ng/ml), while the computed AUCs and elimination half-lives (6-22 hours) proved to be similar after either formulation. Impaired performance was measured in objective tests over the first three hours, the capsule being somewhat more effective than the tablet. Self-assessments indicating subjective sedation returned to the placebo level within 3 hours after the capsule but not after the tablet. This rapid subjective recovery after the capsule might result from an acute tolerance developed after the high peak, and it tallies with the lack of residual sedation previously reported in trials with temazepam 20 mg given in soft gelatine capsules. 相似文献
79.
Yawu Liu Jussi Mattila Miguel ángel Mu?oz Ruiz Teemu Paajanen Juha Koikkalainen Mark van Gils Sanna-Kaisa Herukka Gunhild Waldemar Jyrki L?tj?nen Hilkka Soininen for The Alzheimer’s Disease Neuroimaging Initiative 《PloS one》2013,8(2)
Purpose
To compare the accuracies of predicting AD conversion by using a decision support system (PredictAD tool) and current research criteria of prodromal AD as identified by combinations of episodic memory impairment of hippocampal type and visual assessment of medial temporal lobe atrophy (MTA) on MRI and CSF biomarkers.Methods
Altogether 391 MCI cases (158 AD converters) were selected from the ADNI cohort. All the cases had baseline cognitive tests, MRI and/or CSF levels of Aβ1–42 and Tau. Using baseline data, the status of MCI patients (AD or MCI) three years later was predicted using current diagnostic research guidelines and the PredictAD software tool designed for supporting clinical diagnostics. The data used were 1) clinical criteria for episodic memory loss of the hippocampal type, 2) visual MTA, 3) positive CSF markers, 4) their combinations, and 5) when the PredictAD tool was applied, automatically computed MRI measures were used instead of the visual MTA results. The accuracies of diagnosis were evaluated with the diagnosis made 3 years later.Results
The PredictAD tool achieved the overall accuracy of 72% (sensitivity 73%, specificity 71%) in predicting the AD diagnosis. The corresponding number for a clinician’s prediction with the assistance of the PredictAD tool was 71% (sensitivity 75%, specificity 68%). Diagnosis with the PredictAD tool was significantly better than diagnosis by biomarkers alone or the combinations of clinical diagnosis of hippocampal pattern for the memory loss and biomarkers (p≤0.037).Conclusion
With the assistance of PredictAD tool, the clinician can predict AD conversion more accurately than the current diagnostic criteria. 相似文献80.
Evolution of dispersal is affected by context-specific costs and benefits. One example is sex-biased dispersal in mammals
and birds. While many such patterns have been described, the underlying mechanisms are poorly understood. Here, we study genetic
and phenotypic traits that affect butterfly flight capacity and examine how these traits are related to dispersal in male
and female Glanville fritillary butterflies (Melitaea cinxia). We performed two mark–recapture experiments to examine the associations of individuals’ peak flight metabolic rate (MRpeak) and Pgi genotype with their dispersal in the field. In a third experiment, we studied tethered flight in the laboratory. MRpeak was negatively correlated with dispersal distance in males but the trend was positive in females, and the interaction between
MRpeak and sex was significant for long-distance dispersal. A similar but nonsignificant trend was found in relation to molecular
variation at Pgi, which encodes a glycolytic enzyme: the genotype associated with high MRpeak tended to be less dispersive in males but more dispersive in females. The same pattern was repeated in the tethered flight
experiment: the relationship between MRpeak and flight duration was positive in females but negative in males. These results suggest that females with high flight capacity
are superior in among-population dispersal, which facilitates the spatial spreading of their reproductive effort. In contrast,
males with high flight capacity may express territorial behaviour, and thereby increase the number of matings, whereas inferior
males may be forced to disperse. Thus, flight capacity has opposite associations with dispersal rate in the two sexes. 相似文献