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81.
In order to obtain a system as efficient for collecting particles with a size less than 10 μm (PM10) as removing volatile organic compounds (VOCs), prototype fibrous media containing activated carbon fibers (ACF) associated with non-adsorptive fibers such as cellulose (C) and polyester (PET) fibers have been developed. Influence of process operating parameters on toluene adsorption and particle filtration efficiency was investigated. Particularly, effect of type and ratio of non-adsorptive fibers, degree of beating of cellulose fibers and addition of binders was studied and the impact on physical properties of the medium and its performances for adsorption and particle collection was analyzed.  相似文献   
82.
The selective catalytic reduction (SCR) of NO by n-decane was investigated on a Fe-ZSM-5 prepared by the FeCl3 sublimation method. NO conversion profiles versus temperature were followed in both temperature programmed surface reaction (TPSR, 10 °C min−1) and steady state experiments. A higher NO conversion with a maximum of ca. 80% at 400 °C is observed in the course of the TPSR tests. This phenomenon has been attributed to strong adsorption of n-decane which protects the active sites against the poisoning. Indeed, in steady state experiments at 390 °C the strong decrease of activity as a function of time on stream is due to the polymerisation of conjugated nitriles. This study indicates that long chain alkanes are not the most adequate reductants of NO for high temperature SCR applications. Moreover, due to an easier polymerization of conjugated nitriles on iron zeolites (stronger Fe Lewis sites), this type of catalyst seems less attractive than Cu-zeolite catalysts for the SCR of NO by hydrocarbons in this respect.  相似文献   
83.
Vertical product information flow is important with regard to consumers’ perceptions of the meat which they buy. When research and analysis of traceability is carried out it is often found that critical points where information is systematically lost are encountered in the transformations of the resources. This study describes how lamb meat can be both tracked and traced through a lamb meat producer (company A). At company A 60% of the resource transformations were shown to be additions, mixing and splitting, these are considered to be those which produce the most critical traceability points. After an analysis of the current traceability system at company A suggested improvements were made. With regard to granularity of traceability they cannot trace individual animals during production, but rather a set of animals. The smallest traceable resource unit (TRU) company A can trace back to be a set of (identifiable) animals from one specific farm.  相似文献   
84.
The research aim was to select, compare, and analyze interventions and preventive actions from international bus companies to decrease bus drivers' occupational stress and sickness absenteeism. Through networking, international surveys, and literature study, 13 "natural experiments" were identified with an acceptable research design rating. Interventions were both work and person directed. Principles of worker participation were often followed. The variety in intervention programs, outcome measures, case evaluations, and methodological flaws makes it difficult to present a general picture of program effectiveness. However, analyses on more objective and more subjective outcomes do point at positive effects. This study suggests that stress prevention that combines adequate interventions and proper implementation may be beneficial to both the employee and the company. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
85.
Former industrial sites represent a potential source for food chain contamination if they are converted to residential use where garden practices may be undertaken. In order to assess the risk for human health through vegetable consumption, two research programs were initiated to evaluate the bioavailability of selected PAHs and their potential transfer to edible parts of different vegetables. With this intention, we tested four methods to predict the potential contamination of vegetables growing on polluted soils (wild plant analysis, cropping of vegetables on polluted soils, models of organic pollutant transfer, soil selective chemical extractions). Various wild plant species colonized naturally the contaminated soils of former industrial sites and edible vegetables grew on these soils without symptoms of phytotoxicity. When soils presented concentrations of pollutants compatible with residential land use, no significant concentration of PAHs was measured in the different tissues. Moreover, in soils highly polluted by PAHs significant soil-root-leaf transfers of pollutants were showed, but no PAHs were found in fruits and in storage organs. We noted a similar behavior of cultivated vegetables and of their wild analogous plants facing organic pollutants. In another way, two selective chemical extraction methods correctly evaluated the soil PAH bioavailable fraction for plants growing on low-polluted soil. This would allow the use of wild plants naturally present on polluted soils in parallel with soil chemical extraction methods to assess the risk of contamination of the food chain.  相似文献   
86.
We use liquid–gas microfluidics as a low-cost, tunable microstructuring tool, for which applications can be envisioned in optics. In order to obtain relevant geometries for photonics, beyond simple self-assembled crystals, we propose an original approach that excludes bubbles from chosen zones thanks to tiny pillars. To assess the strength of the exclusion mechanism, we predict the behaviour of a single flattened bubble in front of a thin cylindrical pillar located in a rectangular microchannel. The model compares the hydrodynamic force F fluid that pushes the bubble and the force F s, due to surface tension, resulting from the surface augmentation when the bubble rises over the pillar. The resulting predictions have been confirmed by experimental results which showed that the bubble passes over the pillar if F s < F fluid and goes around it in other cases. Consistently with this model, dynamic bubble crystals with controlled lacuna defects of one, two, or a line of bubbles have been successfully produced. Defects can be switched on or off by changing the flow. Using a photosensitive polymer as a carrier liquid, static bubble crystals have also been produced.  相似文献   
87.
Two expanded granular sludge bed-anaerobic filter (EGSB-AF) bioreactors, R1 and R2, were operated at 15 degrees C for the treatment of toluene-contaminated volatile fatty acid-based wastewater. The seed inoculum and the R1 reactor were unexposed to toluene, prior to and during the trial, respectively. Both reactors were operated at a hydraulic retention time of 24h at applied organic loading rates of 0.71-1.43kg chemical oxygen demand (COD)m(-3)d(-1). Toluene was supplemented to the R2 influent at concentrations of 5-104 mg toluenel(-1) (solubilised in ethanol). Bioreactor performance was evaluated by COD and toluene removal efficiency, and the methane content of biogas (%). Specific methanogenic activity and toxicity assays were employed to investigate the activity and toluene toxicity thresholds of key trophic groups, respectively, within the seed and reactor biomass samples. COD and toluene removal efficiencies of 70-90% and 55-99%, respectively, were achieved during the 630-d trial. Metabolic assays suggested that a psychrotolerant H(2)/CO(2)-utilizing methanogenic community developed in the toluene-degrading biomass. The results indicate the viability of low-temperature anaerobic digestion for the treatment of wastewater containing toluene.  相似文献   
88.
In this paper, electrochemical and optical characterizations of anodic porous n-InP(1 0 0) are reported. The direct relation between the observed pore morphology and the physical properties is demonstrated using electrochemical methods such as cyclic voltammetry and impedance spectroscopy as well as optical techniques like photocurrent spectroscopy and photoluminescence measurements. An enhancement of the interfacial capacitance, proportional to the anodic charge, is revealed by voltammetry and Mott-Schottky analysis. It is related to the drastic increase of the area of the porous electrode. However, when the porous samples are sufficiently reverse-biased, the capacitance enlargement disappears because the nanosized pore walls are fully depleted and the electroactive area recovers its initial value. Photocurrent spectroscopy and photoluminescence measurements show the porous film behaves like an absorbent layer. This effect is also ascribed to the specific geometry of the space charge layer within the pore walls. A model based on the absorption coefficient and the effective optical path length is thus used to describe the phenomenon. However the model is not sufficient to depict the phenomenon and the charge recombination in the additional surface states created during the pore formation and the long transit time of electrons in the porous matrix are also significant. Additional effects such as the initial enhancement of the photocurrent response and the redshift of the absorption edge of the photocurrent spectra are observed. Inversely, no shift of the photoluminescence peak is detected. However an exponential quenching of the photoluminescence is also attributed to an absorbent behavior of the porous layer.  相似文献   
89.
We report on results of fabrication and optical characterisation of sub-250 nm periodic gold nanohole arrays on glass by using UV nanoimprint lithography (UV-NIL) combined with both reactive ion etching (RIE) and Cr/Au lift-off processes. The transmission spectra of the fabricated nanohole gratings were measured for different hole diameters and periods. We also show preliminary results of chemical sensing after surface modification of the gold hole arrays. In agreement with the theoretical prediction, we found that any change in the dielectric index of the surrounding environment of the metallic array produces a transmission peak red shift.  相似文献   
90.
Using a within-subject design, this study investigated the situational-specificity hypothesis, namely that alcohol outcome expectancies (AOEs), subjective evaluations of AOEs, and the speed with which AOEs are accessed from memory vary as a function of environmental setting. Thirty-nine undergraduates (20 women), of legal drinking age, responded to the Comprehensive Effects of Alcohol questionnaire (K. Fromme, E. Stroot, & D. Kaplan, 1993) that was presented on a laptop computer in 2 counterbalanced contexts: a laboratory setting and an on-campus bar. Response latencies served as dependent measures for memory accessibility. Consistent with previous research (A.-M. Wall, S. A. McKee, & R. E. Hinson, 2000), evidence in support of the situational-specificity hypothesis was found. Specifically, environmental context influenced undergraduates' expectations concerning alcohol's effects and subjective evaluations of AOEs, as well as the speed with which specific AOEs were accessed from memory. Overall, these findings suggest the need for greater attention to situational variation in AOEs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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