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1.
The specificity of various child characteristics and environmental correlates of childhood internalizing and externalizing problems was examined using both cross-sectional and longitudinal analyses (from ages 2–3 and 4–5 years) in a general population sample of 10–11-year-olds. Specificity was defined according to a between-subjects and a within-subjects method, using parent and teacher reports of psychopathology. Temperamental withdrawal, parental internalizing psychopathology, and early single parenthood (for girls) were identified as correlates that are specific for internalizing problems, whereas temperamental high general activity level was identified as externalizing-specific. Further, parenting stress, poor school results (only for boys), and stressful life events (only for girls) were found to be common correlates of psychopathology. Research implications regarding the findings and the use of a within-subjects method are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
2.
Organic production benefits from fair competition and sustained consumer confidence. The latter can only be assured by paper trailing and verification assessments. Traditional analytical strategies for guaranteeing quality and uncovering adulteration have relied on the determination of the amount of a marker compound or compounds in a material and a subsequent comparison of the value(s) obtained with those established for equivalent material. Since it is unlikely to find a unique marker that allows discrimination between organic and conventional produce, selective fingerprinting (profiling) combined with chemometrics is a more promising approach. In this study, carotenoid High Performance Liquid Chromatography–Diode Array Detection profiling combined with k-nearest neighbour classification chemometrics was used to predict the production system (organic vs. non-organic) of chicken eggs. A proof-of-concept set (training set for the model) was composed of eggs from 24 organic farms, 12 free range, and 12 barn farms in the Netherlands. The identities of organic, free range, and barn eggs were predicted with success rates of 100%, 100%, and 84%, respectively. The identity of eggs determined using an additional market test set with eggs from 12 organic, 12 free range, and 12 barn farms originating from the Netherlands and New Zealand resulted in correct classifications for 35 of the 36 samples. The results of this study indicate that this fingerprint approach is a promising tool for analytical verification of the production system of organic eggs.  相似文献   
3.
The volatile compositions of 192 olive oil samples from five different European countries were investigated by PTR-MS sample headspace analysis. The mass spectra of all samples showed many masses with high abundances, indicating the complex VOC composition of olive oil. Three different PLS-DA models were fitted to the data to classify samples into ‘country’, ‘region’ and ‘district’ of origin, respectively. Correct classification rates were assessed by cross-validation. The first fitted model produced an 86% success rate in classifying the samples into their country of origin. The second model, which was fitted to the Italian oils only, also demonstrated satisfactory results, with 74% of samples successfully classified into region of origin. The third model, classifying the Italian samples into district of origin, yielded a success rate of only 52%. This lower success rate might be due to either the small class set, or to genuine similarities between olive oil VOC compositions on this tight scale.  相似文献   
4.
The main goal of this work was to propose an authentication model based on the phenolic composition and antioxidant and metal chelating capacities of purple grape juices produced in Brazil and Europe in order to assess their typicality. For this purpose, organic, conventional, and biodynamic grape juices produced in Brazil (n = 65) and in Europe (n = 31) were analyzed and different multivariate class‐modeling and classification statistical techniques were employed to differentiate juices based on the geographical origin and crop system. Overall, Brazilian juices, regardless of the crop system adopted, presented higher contents of total phenolic compounds and flavonoids, total monomeric anthocyanins, proanthocyanidins, flavonols, flavanols, cyanidin‐3‐glucoside, delphinidin‐3‐glucoside, and malvidin‐3,5‐glucoside. No differences were observed for trans‐resveratrol, malvidin‐3‐glucoside, and pelargonidin‐3‐glucoside between countries and among crop systems. A total of 91% of Brazilian and 97% of European juices were adroitly classified using partial least squares discriminant analysis when the producing region was considered (92% efficiency), in which the free‐radical scavenging activity toward 2,2‐diphenyl‐1‐picrylhydrazyl, content of total phenolic compounds, gallic acid, and malvidin‐3‐glucoside were the variables responsible for the classification. Intraregional models based on soft independent modeling of class analogy were able to differentiate organic from conventional Brazilian juices as well as conventional and organic/biodynamic European juices.  相似文献   
5.
OBJECTIVE: To study the prevalence, incidence and predictive value for progression to AIDS of the HIV-1 syncytium-inducing (SI) phenotype in HIV-infected injecting drug users (IDU) compared with HIV-infected homosexual men. DESIGN: Two prospective cohort studies on HIV-1 infection among IDU and homosexual men. METHODS: HIV-infected IDU (n = 225) and homosexual men (n = 366) without AIDS were studied from March 1989 through December 1993. Data on laboratory markers, including the presence of SI variants, demographics, behavioural characteristics and clinical events were collected at every visit. RESULTS: At baseline, SI variants were detected in 4% of IDU and 17% of homosexual men. During the study period 18 IDU and 68 homosexual men switched from non-SI to SI phenotype (4-year cumulative incidence, 14.6 and 28.4%, respectively) before AIDS diagnosis. Among participants with a documented date of HIV infection the cumulative incidence of SI was lower among IDU than homosexual men (4-year cumulative incidence, 6.2 and 20.7%, respectively). At AIDS diagnosis, 21% of all AIDS cases among IDU had the SI phenotype compared with 54% among homosexual men. In both risk groups an accelerated CD4 decline was found after the non-SI-to-SI switch. The SI phenotype appeared to be a predictor of AIDS (multivariate relative hazard, 5.33), independent of CD4 cell count and p24 antigen at baseline. In the multivariate time-dependent analysis, the relative hazard of SI phenotype decreased considerably, which is consistent with the hypothesis that the effect of SI phenotype on progression to AIDS is mediated by CD4 cell count. CONCLUSION: The SI phenotype is associated with accelerated CD4 decline and progression to AIDS in both risk groups. The remarkable lower prevalence and incidence of the SI phenotype among IDU may implicate a difference in pathogenesis and natural history of HIV infection linked to transmission group.  相似文献   
6.
Homogeneous thin films of zinc titanate have been successfully prepared on Si(100) wafers by depositing a film of zinc and titanium oxides (ZnO-TiO2) by low-pressure metalorganic chemical vapor deposition (MOCVD), followed by an annealing treatment. The precursors used for the deposition were diethylzinc (DEZ), tetraisopropoxide titanium (TPT), and water. By performing the deposition at temperatures between 140 and 350C, the stoichiometry of the as-deposited films could be effectively controlled over Zn/Ti ratios between 0.5 and 2.5, which cover the composition of various zinc titanate phases identified in the literature. The as-deposited ZnO-TiO2 films are amorphous, and possess a fairly smooth surface. XPS and SIMS analysis showed that the composition of these films is uniform over the wafer as well as through the films bulk. An annealing treatment of the as-deposited films at high temperature  相似文献   
7.
The home-based intervention program Video-feedback Intervention to promote Positive Parenting and Sensitive Discipline (VIPP-SD) was tested in a randomized controlled trial with 237 families screened for their 1- to 3-year-old children's relatively high scores on externalizing behavior. VIPP-SD, based on attachment theory and coercion theory, focuses on mirroring and discussing actual parent-child interactions in six 1.5-hr sessions with individual families at home. VIPP-SD proved to be effective in enhancing maternal attitudes toward sensitivity and sensitive discipline and in promoting sensitive discipline interactions in the intervention group as compared with the control group. Moreover, in families with more marital discord and in families with more daily hassles, the intervention resulted in a decrease of overactive problem behaviors in the children. The authors conclude that VIPP-SD should become an important module in attachment-based interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
8.
This study investigated the interaction of child temperament and maternal discipline in the prediction of externalizing problems in early childhood. Interaction effects were evaluated in a sample of 227 one- to three-year-old children with relatively high externalizing problems scores on the Child Behavior Checklist/1 1/2-5. Child temperament was reported by the mothers, maternal discipline was observed in a laboratory session, and child outcome measures included both mother-reported externalizing problems and observed physical aggression. Results indicate that children with difficult temperaments are more susceptible to negative discipline (i.e., they showed more externalizing problems) as well as more susceptible to positive discipline (i.e., they showed fewer externalizing problems and less physical aggression), as compared with children with relatively easy temperaments. These findings provide empirical evidence for the differential susceptibility hypothesis and suggest directions for enhancing the effectiveness of interventions aimed at reducing early childhood externalizing problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
Solid-liquid phase diagrams of 15 binary common-ion alkali halide mixtures, showing negligible solid miscibility, have been analyzed using the EXTXD/SIVAMIN method. The principles of and the philosophy behind the method, which permits the simultaneous derivation of the excess enthalpy and excess entropy functions from a single TX phase diagram, are discussed. The significance of the results is investigated by recalculating the phase diagrams and by comparing the excess enthalpy functions with experimental heats of mixing.  相似文献   
10.
In this study, the authors used a randomized controlled trial to explore the link between having positive peer relations and externalizing outcomes in 758 children followed from kindergarten to the end of 2nd grade. Children were randomly assigned to the Good Behavior Game (GBG), a universal classroom-based preventive intervention, or a control condition. Children’s acceptance by peers, their number of mutual friends, and their proximity to others were assessed annually through peer ratings. Externalizing behavior was annually rated by teachers. Reductions in children’s externalizing behavior and improvements in positive peer relations were found among GBG children, as compared with control-group children. Reductions in externalizing behavior appeared to be partly mediated by the improvements in peer acceptance. This mediating role of peer acceptance was found for boys only. The results suggest that positive peer relations are not just markers, but they are environmental mediators of boys’ externalizing behavior development. Implications for research and prevention are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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