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31.
CFD as an approach to understand flammable dust 20 L standard test: Effect of the ignition time on the fluid flow 下载免费PDF全文
Daniel Vizcaya Andrés Pinilla Mariangel Amín Nicolás Ratkovich Felipe Munoz Carlos Murillo Nathalie Bardin‐Monnier Olivier Dufaud 《American Institute of Chemical Engineers》2018,64(1):42-54
A computational study based on the Euler–Lagrange approach was developed for the characterization of flammable dusts in the 20 L sphere standard test. The aim of the study was to analyze some parameters that might affect the experimental data (e.g., cold turbulence and particle size). The turbulence of a wheat starch cloud was described with the Detached Eddy Simulation model. Both the pressure of the system and the RMS velocity were compared with the flow patterns established with a particle image velocimetry analysis. It was concluded that the rebound nozzle forms a cloud that is composed by clumps. This fact implies dissimilarities between the local concentrations and the nominal value. Finally, a granulometric analysis established that the mean diameter of the particle size distribution (PSD) decreased by 69% during the dispersion. Thus, it is suggested to consider the PSD at the ignition zone rather than the PSD of the sample. © 2017 American Institute of Chemical Engineers AIChE J, 63: 42–54, 2018 相似文献
32.
Vítor J.P. Vilar Tânia F.C.V. Silva Marcos A.N. Santos Amélia Fonseca Isabel Saraiva Rui A.R. Boaventura 《Solar Energy》2012,86(11):3301-3315
The main purpose of this work is to study the treatment of a leachate after preliminary aerated lagooning by a solar photo-Fenton process, using a photocatalytic reactor with compound parabolic collectors (CPCs). The influence of different process parameters in the reaction rate was evaluated, such as, the type of acid used in the acidification step (H2SO4, HCl, H2SO4 + HCl); type of iron salt (FeSO4, FeCl3) and respective iron concentration (60, 80, 100 and 140 mg Fe2+/L); temperature; and ratio of illuminated to total volume (25 L/35 L; 25 L/72 L). DOC abatement in the acidification procedure is independent of the type of acid used and temperature, and is related principally with the precipitation of humic acids. The use of HCl alone or in combination with H2SO4 leads to a substantially increase of the chloride ions, leading to the formation of less reactive chloride radicals when compared with sulfate radicals, decreasing the photo-Fenton reaction rate. The use of ferrous ions instead of ferric ions influenced positively the photo-Fenton reaction. Meteorological conditions favoring higher temperature of the leachate enhance the photo-Fenton reaction. Alternating dark and illumination intervals has shown a negligible effect on the illumination time needed to achieve the same mineralization, indicating that the Fenton process that takes place in dark zones is not efficient, even in the degradation of intermediate compounds resulting from the light-enhanced reaction. According to biodegradability tests, the optimum energy dose, necessary to obtain a biodegradable effluent, is 57.4 kJUV/L, consuming 120 mM of H2O2 and leading to a final DOC of 284 mg/L which corresponds to approximately 66% of mineralization. 相似文献
33.
Sébastien Fritz Chris Hoze Emmanuelle Rebours Anne Barbat Méline Bizard Amanda Chamberlain Clémentine Escouflaire Christy Vander Jagt Mekki Boussaha Cécile Grohs Aurélie Allais-Bonnet Maëlle Philippe Amélie Vallée Yves Amigues Benjamin J. Hayes Didier Boichard Aurélien Capitan 《Journal of dairy science》2018,101(7):6220-6231
34.
S. E. Stewart M. D. Parker A. Amézquita T. L. Pitt 《International journal of cosmetic science》2016,38(6):634-645
Regulatory decisions regarding microbiological safety of cosmetics and personal care products are primarily hazard‐based, where the presence of a potential pathogen determines decision‐making. This contrasts with the Food industry where it is a commonplace to use a risk‐based approach for ensuring microbiological safety. A risk‐based approach allows consideration of the degree of exposure to assess unacceptable health risks. As there can be a number of advantages in using a risk‐based approach to safety, this study explores the Codex Alimentarius (Codex) four‐step Microbiological Risk Assessment (MRA) framework frequently used in the Food industry and examines how it can be applied to the safety assessment of personal care products. The hazard identification and hazard characterization steps (one and two) of the Codex MRA framework consider the main microorganisms of concern. These are addressed by reviewing the current industry guidelines for objectionable organisms and analysing reports of contaminated products notified by government agencies over a recent 5‐year period, together with examples of reported outbreaks. Data related to estimation of exposure (step three) are discussed, and examples of possible calculations and references are included. The fourth step, performed by the risk assessor (risk characterization), is specific to each assessment and brings together the information from the first three steps to assess the risk. Although there are very few documented uses of the MRA approach for personal care products, this study illustrates that it is a practicable and sound approach for producing products that are safe by design. It can be helpful in the context of designing products and processes going to market and with setting of microbiological specifications. Additionally, it can be applied reactively to facilitate decision‐making when contaminated products are released on to the marketplace. Currently, the knowledge available may only allow a qualitative or semi‐quantitative rather than fully quantitative risk assessment, but an added benefit is that the disciplined structuring of available knowledge enables clear identification of gaps to target resources and if appropriate, instigate data generation. 相似文献
35.
Antimicrobial Activity of Marjoram (Origanum Majorana) Essential Oil Against the Multidrug‐Resistant Salmonella Enterica Serovar Schwarzengrund Inoculated in Vegetables from Organic Farming 下载免费PDF全文
36.
In make-to-order (MTO)/engineer-to-order (ETO) business environments multiple customer-oriented projects compete for and share resources through interdependent engineering and production activities. Deep knowledge of critical dimensions that affect performance is key in this context. For this, we propose a set of determinants – workload, complexity, outsourcing, design reuse, project type, and knowledge/experience with technology, that impact performance. These determinants are input to an extended hybrid simulation model using system dynamics (SD), discrete event simulation (DES) and agent-based simulation (ABS) that tackles the needs imposed by activities of very different nature, as the project development and manufacturing/assembly operations. The hybrid model is applied to the case of an advanced manufacturing company. Through Monte Carlo sampling, the influence of different combinations of determinants in the performance variability is assessed. A correlation analysis shows evidence of association between all performance determinants and the project time and cost, while no evidence of association between the design reuse and project type determinants and the manufacturing and assembly time. 相似文献
37.
Youngsun Kim Soyoun An Sinae Kim Jung Ho Park Han Am Son Hyun Tae Kim Kyung-Do Suh Jin Woong Kim 《Polymer》2013
This study introduces a synthetic method to graft zwitterionic poly (2-methacryroyloxyethyl phosphoryl choline) brushes onto TiO2 nanoparticles with thickness of a few nanometers. The grafting of zwitterionic polymer brushes was characterized by electron microscope measurements, zeta-potential analysis, and thermo-gravimetric analysis. The technique we employed to synthesize those hybrid nanoparticles was a modified seeded emulsion polymerization in which the polymerization loci were changed in the stage of radical initiation and chain propagation. We have found that the polymerization loci should be on the surface for achieving the effective grafting of polymer brushes. From the suspension rheology studies, we have observed that the suspension of our hybrid nanoparticles was dominated by the attractive force as well as by packing volume effect. This unique rheological behavior is expected to be useful for understanding the inter-particle interactions in complex formulations. 相似文献
38.
Amélia H. U. Torres Jean-Pierre Habas 《Polymer-Plastics Technology and Engineering》2013,52(15):1594-1599
The effects caused upon the physicochemical behavior of high-density polyethylene pipes by exposure to a diesel lubricant were investigated, as a function of time and temperature, by thermogravimetric and gravimetric analysis and by FT-IR. The gravimetric data were satisfactorily described using Fick's law. The fitting of the experimental points showed that diesel, which can be regarded as a model fluid to analyze the effects caused by aromatic unities present in oil derivatives, has a high diffusion rate into HDPE. The FT-IR results showed that no main structural modifications have occurred after exposure, besides solubilization of low molecular weight units. From the analysis performed, physical aging was identified as the aging process occurring when the HDPE pipes came in contact with diesel lubricant. 相似文献
39.
Manel Issaoui Mahfoudhi Nesrine Guido Flamini Amélia Delgado 《International Journal of Food Science & Technology》2021,56(7):3166-3178
Aiming at increasing the nutritional value and sensory quality of bread, we assessed the enrichment of white flour with different levels of powdered cinnamon and pomegranate peel, through rheological, nutritional, aromatic, textural and sensory analyses. These extra ingredients were chosen for their richness in bioactive compounds, and they differently affected bread quality. In relation to raw flour, introduced ingredients slightly decreased moisture and protein content, while increasing ash, fibre and radical scavenging activity, which can be attributed to the sharing of aromatic compounds by cinnamon and pomegranate peel during the bread making process. When cinnamon was incorporated at 1%, the content of all furan derivatives was reduced up to 1/4 of initial value, 2-pentyl furan totally disappeared, and furfuryl alcohol was reduced to 2.1%. Despite enriched bread’s texture was slightly worse, it was still acceptable in sensory tests, as 150 interviewed naive consumers preferred the new product over the control. 相似文献
40.
Amélie Keller Maria Stougård Peder Frederiksen Fanney Thorsteinsdottir Allan Vaag Peter Damm Ramune Jacobsen Berit L. Heitmann 《Nutrition journal》2018,17(1):100