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61.
The performance of powder coatings on hot-dip galvanized steel has been studied by testing in 5 years field exposure in marine and industrial atmospheres, as well as in accelerated tests. The aim was to assess the quality of such coating systems in corrosive environments and to establish criteria for how to obtain good quality. The test data demonstrates that polyester powder coatings are a good alternative to wet paint as top coat on hot-dip galvanized steel. The phosphate layer is identified as the most crucial step to ensure high quality. Recommendations for how to obtain good quality are provided.  相似文献   
62.

Background  

Particles are known to induce both cytokine release (MIP-2, TNF-α), a reduction in cell viability and an increased apoptosis in alveolar macrophages. To examine whether these responses are triggered by the same particle determinants, alveolar macrophages were exposed in vitro to mineral particles of different physical-chemical properties.  相似文献   
63.
The objective of this study was to test the possibility of using lipid profiles obtained by gas chromatography (GC) and 13C nuclear magnetic resonance (NMR) in authentication of cod liver oils according to wild/farmed and geographical origin. GC and 13C-NMR data of cod liver oil from wild and farmed fish from different locations in Norway and Scotland were obtained, and analyzed by principal component analysis (PCA) and linear discriminant analysis (LDA) to test if it was possible to differentiate oil from wild and cultured cod (Gadus morhua L.), and to further elucidate differences between fish from the different farms/catch area. Cod liver oils of wild and farmed origin were clearly separated in the PCA score plot both from GC and NMR data. From NMR data it was also possible to observe groupings based on geographical origin (farm/catch area) of the different samples. Using LDA with cross validation the wild/farmed classification rates were 97% for GC data and 100% for NMR data. In the classification of cod liver oils according to geographical origin (38 samples from six different farms/catch area), the correct classification rate was 63% for GC data and 95% for NMR data.  相似文献   
64.
There is a desire in the food industry to be able to estimate the oxygen transmission rate (OTR) of packages by knowing the permeability data of unconverted sheet/film, instead of measuring the OTR of packages. Due to thermoforming, the permeability of a material changes and therefore it is difficult to estimate the permeability (OTR) of converted trays from the OTR values of unconverted material. This paper evaluates the possibilities and limitations of predicting the OTR of thermoformed trays. Different methods for the calculation of OTR due to thickness measurements were compared. The use of theoretical thickness was satisfactory in the calculation of OTR of trays based on the OTR of unconverted sheet, area and thickness. Both linear and quadratic regression models were evaluated. Validation of the regression models was made by comparing the measured and calculated OTR of trays made of PS/EVOH/PE, A‐PET/PE, PS/PE and PP/PE. These trays were manufactured on different thermoforming machines, different processing parameters and different sizes of mould. None of the models (linear and quadratic) were suitable for the calculation of OTR of trays made of PS/PE and PP/PE. Both linear and quadratic models gave satisfactory agreement with measured values for trays made of both PS/EVOH/PE and A‐PET/PE. This case study indicates that a general equation for the calculation of OTR for different polymer combinations was not possible to generate. The equations presented in this paper are strictly applicable only for the polymer combinations used in this experiment, and can not be considered as general equations. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
65.
The paper presents an improved version of a previously published model for the diffuse fraction of hourly global irradiance. In addition to hourly solar elevation and clearness index, an hour-to-hour variability index and regional surface albedo are included among the input parameters. Moreover, to prevent excessively high normal incidence beam irradiances at very low solar elevations, the model does not allow a solar elevation dependent maximum beam transmittance to be exceeded. This new model is tuned to 32 years of data from Bergen, Norway. Moreover, a test against independent data from four European stations showed that the model performs better than the models of Erbs et al. (1982), Maxwell (1987) and Perez et al. (1992).  相似文献   
66.
The aim of this study was to use 13C-nuclear magnetic resonance (NMR) regiospecific analyses of triacylglycerols to distinguish fish oils from different fish species for authentication purposes. 13C-NMR data of muscle lipids from Atlantic salmon (Salmo salar L.), mackerel (Scomber scombrus) and herring (Clupea harengus) were obtained, and the distribution of omega-3 polyunsaturated fatty acids between the sn-1,3 and sn-2 glycerol chains calculated from the carbonyl region. The results show that there were significant differences in the sn-2 position specificity of the fatty acids 22:6n-3, 20:5n-3 and 18:4n-3 among the species investigated. The most pronounced difference was that herring had a higher proportion of its 22:6n-3 in the sn-2 position compared to the two other species. Principal component analysis of data points in the carbonyl-region showed that there were also differences in the level and regiospecific distribution of monounsaturated/saturated fatty acids, which made it possible to distinguish oils of these three species solely from the carbonyl region of 13C-NMR spectra.  相似文献   
67.
This paper presents the main findings in the EU PARTNER Project (2002-2006) providing the basis for a unified European test approach for evaluating the potential alkali-reactivity of aggregates. The project evaluated the tests developed by RILEM and some regional tests for their suitability for use with the wide variety of aggregates and geological types found across Europe. The project had 24 partners from 14 countries, covering most of Europe, from Iceland to Greece. 22 different types of aggregates from 10 different European countries were evaluated. It was found that in most cases the RILEM tests could successfully identify the reactivity of the aggregates tested. They were most successful with normally reactive and non-reactive aggregates, but with aggregates that react very slowly an extended test period may be necessary for some of the RILEM methods. Overall, the accelerated mortar bar test and the accelerated concrete prism test seemed most effective and to have the best precision.  相似文献   
68.
A hybrid approach was applied for the design of an inhibitor of trypsin‐like serine proteases. Compound 16 [(R,R)‐ and (R,S)‐diphenyl (4‐(1‐(4‐amidinobenzylamino)‐1‐oxo‐3‐phenylpropan‐2‐ylcarbamoyl)phenylamino)(4‐amidinophenyl)methylphosphonate hydrochloride], prepared in a convergent synthetic procedure, possesses a phosphonate warhead prone to react with the active site serine residue in a covalent, irreversible manner. Each of the two benzamidine moieties of 16 can potentially be accommodated in the S1 pocket of the target enzyme, but only the benzamidine close to the phosphonate group would then promote an irreversible interaction. The Janus‐faced inhibitor 16 was evaluated against several serine proteases and caused a pronounced inactivation of human thrombin with a second‐order rate constant (kinac/Ki) of 59 500 M ?1 s?1. With human matriptase, 16 showed preference for a reversible mode of inhibition (IC50=2.6 μM ) as indicated by linear progress curves and enzyme reactivation.  相似文献   
69.
The cell‐surface serine protease matriptase‐2 is a critical stimulator of iron absorption by negatively regulating hepcidin, the key hormone of iron homeostasis. Thus, it has attracted much attention as a target in primary and secondary iron overload diseases. Here, we have characterised Kunitz‐type inhibitors hepatocyte growth factor activator inhibitor 1 (HAI‐1) and HAI‐2 as powerful, slow‐binding matriptase‐2 inhibitors. The binding modes of the matriptase‐2–HAI complexes were suggested by molecular modelling. Different assays, including cell‐free and cell‐based measurements of matriptase‐2 activity, determination of inhibition constants and evaluation of matriptase‐2 inhibition by analysis of downstream effects in human liver cells, demonstrated that matriptase‐2 is an excellent target for Kunitz inhibitors. In particular, HAI‐2 is considered a promising scaffold for the design of potent and selective matriptase‐2 inhibitors.  相似文献   
70.
The Norwegian driver education programme is extensive, systematic and comprehensive. The syllabus intentions have high expectations for pupil learning, and in the learning situation the ability of teachers to utilise dialogue as an effective learning tool is put to the test. Over a 5-year period we have studied learning situations in all areas of the Norwegian driver education programme. In this article we present findings based on observations of teacher-pupil interaction during on-road practice and discuss how teachers may form the dialogue into an effective learning tool in order to tap the learning potential that is embedded in driver education programmes. The education of responsible drivers requires that teacher-pupil dialogues bring about a shared understanding of a full traffic context during on-road practice. It becomes evident that different teacher supportive approaches pave the way to ‘intersubjectivity’ of occurring traffic contexts in qualitatively different ways. Teachers use both ‘clarifying’ and ‘elaborative’ processes to prepare the learner for responsible driving. The establishment of a mutual understanding is a continuous dialogical process in which concepts become mediating tools. How the two conceptual worlds of teacher and learner merge makes a basic level for subsequent scaffolding processes during on-road practice.  相似文献   
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