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101.
A compact, internally heated, catalytic reactor is demonstrated for the low-temperature oxidation of carbon monoxide. Carbon
nanofibres were grown on carbon felt and used as a support material for Au/TiO2 catalysts. The carbon composite plays two roles; as a support material for the catalyst and for providing heat to the reaction
by the Joule effect. The internal heating offers a stable reactor system with quick temperature response at relatively low
energy input. Comparison between external and internal heating shows higher conversion of CO in the low-temperature range
when using internal heating. The Au/TiO2 catalyst supported on the carbon-carbon composite shows good stability at 250°C. 相似文献
102.
We report the synergistic, rapid gelation of solutions of isotactic polypropylene (i-PP) and the nucleating agent 1,3:2,4-bis-(3,4-dimethyl benzylidene) sorbitol (DMDBS) in decalin. Cooling to room temperature of a solution comprising, for instance, 3.0 wt% of a moderately high molecular weight i-PP (Mv=1.3×106 g/mol) and as little as 0.0075 wt% DMDBS (0.25 wt% based on the polymer) resulted in the fast formation of highly ductile gels. In reference experiments without DMDBS, often ‘mud-cracked’, brittle polymer films were obtained, and decaline solutions of DMDBS alone at the above concentration did not form macroscopically coherent gels. In the present work we employed this useful occurrence for gel-processing/drawing of i-PP, yielding material with Young's moduli of 35 GPa, tensile strengths of approximately 1 GPa and melting temperatures measured for constrained samples as high as 228 °C. 相似文献
103.
Magnus Oskarsson Kalle Åström Niels Chr. Overgaard 《Journal of Mathematical Imaging and Vision》2006,26(3):327-343
In this paper we investigate the structure and motion problem for calibrated one-dimensional projections of a two-dimensional environment. The theory of one-dimensional cameras are useful in several areas, e.g. within robotics, autonomous guided vehicles, projection of lines in ordinary vision and vision of vehicles undergoing so called planar motion. In a previous paper the structure and motion problem for all cases with non-missing data was classified and solved. Our aim is here to classify all structure and motion problems, even those with missing data, and to solve them. In the classification we introduce the notion of a prime problem. A prime problem is a minimal problem that does not contain a minimal problem as a sub-problem. We further show that there are infinitely many such prime problems. We give solutions to four prime problems, and using the duality of Carlsson these can be extended to solutions of seven prime problems. Finally we give some experimental results based on synthetic data. 相似文献
104.
Antifouling agent release from marine coatings-ion pair formation/dissolution for controlled release 总被引:2,自引:0,他引:2
In marine coatings, the ability to sustain constant release of antifouling agents (AFA(s)) over a long period of time has become increasingly important. One efficient approach to prevent that diffusion depletes the paint film's antifouling activity is to adsorb the AFA strongly to a specie with low translational mobility, such as a high molecular weight polymer. Therefore, the AFA, Medetomidine, was adsorbed onto a sulfonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SDPS) generating a Medetomidine–SDPS ion pair in an organic solvent. The interaction was investigated by 1H NMR in butanol (BuOH-d10) and on solid surfaces by the quartz crystal microbalance with dissipation monitoring technique (QCM-D) in two different solvents, seawater and o-xylene. From the NMR studies in butanol (BuOH-d10), a strong interaction between Medetomidine and SDPS was observed. From the QCM-D measurements, differences in affinity between Medetomidine and the SDPS was observed when changing from seawater to o-xylene. In seawater, the interaction was weak and displayed a large degree of reversibility compared to in o-xylene, where the interaction was strong and almost irreversible. Different swelling behaviour was also observed at the solid surfaces depending on the solvent used with o-xylene exhibiting the largest swelling of the polymer layer. 相似文献
105.
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107.
Per-Anders Carlsson Magnus Skoglundh Erik Fridell Edward Jobson Bengt Andersson 《Catalysis Today》2002,73(3-4):307-313
The effect of gas composition changes on the low temperature activity for supported platinum model catalysts has been studied. By introducing well-controlled periodic O2 pulses to a simple diluted gas mixture of CO and O2, a substantial improvement of the low temperature oxidation activity was observed. The reason for low activity on noble metals at low temperatures is often attributed to self-poisoning by CO. The improved catalytic performance observed is proposed to origin from the transients causing a surface reactant composition that is favourable for the reaction rate, i.e. lower degree of self-poisoning. This was also confirmed by in situ Fourier transform infrared (FT-IR) spectroscopy in combination with mass spectrometry (MS) measurements, which gave evidence for the existence of a strong interplay between the gas phase concentration and the adsorbate composition for these catalysts. 相似文献
108.
Kristiina Laine Kristoffer Segerholm Magnus Wålinder Lauri Rautkari Graham Ormondroyd Mark Hughes Dennis Jones 《Journal of Materials Science》2014,49(5):2027-2034
Scots pine (Pinus sylvestris L.) wood was surface densified in its radial direction in an open press with one heated plate to obtain a higher density on the wood surface whilst retaining the overall thickness of the sample. This study investigated the effect of temperature (100, 150 and 200 °C) and press closing speed (5, 10 and 30 mm/min, giving closing times of 60, 30 and 10 s, respectively) on the micromorphology of the cell-wall, as well as changes occurring during set-recovery of the densified wood. The micromorphology was analysed using scanning electron microscopy (SEM) combined with a sample preparation technique based on ultraviolet-excimer laser ablation. Furthermore, the density profiles of the samples were measured. Low press temperature (100 °C) and short closing time (10 s) resulted in more deformation through the whole thickness, whilst increasing the temperature (150 and 200 °C) and prolonging the closing time (30 and 60 s) enabled more targeted deformation closer to the heated plate. The deformation occurred in the earlywood regions as curling and twisting of the radial cell-walls, however, no apparent cell-wall disruption or internal fracture was observed, even at low temperatures and fast press closing speed, nor after soaking and drying of the samples. In the SEM-analysis after soaking and drying, it was noticed that the cells did not completely recover their original form. Thus, part of the deformation was considered permanent perhaps due to viscoelastic flow and plastic deformation of the cell-wall components. 相似文献
109.
Detection of Glutamate and Acetylcholine with Organic Electrochemical Transistors Based on Conducting Polymer/Platinum Nanoparticle Composites
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110.
The uncertainty and cost of changing from a fossil-fuel-based society to a hydrogen-based society are considered to be extensive obstacles to the introduction of fuel cell vehicles (FCVs). The absence of existing profitable refueling stations has been shown to be one of the major barriers. This paper investigates methods for calculating an optimal transition from a gasoline refueling station to future methane and hydrogen combined use with an on site small-scale reformer for methane. In particular, we look into the problem of matching the hydrogen capacity of a single refueling station to an increasing demand. Based on an assumed future development scenario, optimal investment strategies are calculated. First, a constant utilization of the hydrogen reformer is assumed in order to find the minimum hydrogen production cost. Second, when considerations such as periodic maintenance are taken into account, optimal control is used to concurrently find both a short term equipment variable utilization for one week and a long term strategy. The result is a minimum hydrogen production cost of $4–6/kg, depending on the number of reinvestments during a 20 year period. The solution is shown to yield minimum hydrogen production cost for the individual refueling station, but the solution is sensitive to variations in the scenario parameters. 相似文献