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261.
Parametric study of an HVOF process for the deposition of nanostructured WC-Co coatings 总被引:1,自引:1,他引:1
Bartuli Cecilia Valente Teodoro Cipri Fabio Bemporad Edoardo Tului Mario 《Journal of Thermal Spray Technology》2005,14(2):187-195
Nanocrystalline WC-Co coatings were deposited by high velocity oxyfuel from commercial nanostructured composite powders. Processing
parameters were optimized for maximal retention of the nanocrystalline size and for minimal decarburation of the ceramic reinforcement.
Thermochemical and gas-dynamical properties of gas and particle flows within the combustion flame were identified in various
operating conditions by computational fluid-dynamics (CFD) simulation. Significant improvements of the mechanical properties
of the coatings were obtained: a decrease of the friction coefficient was measured for the nanostructured coatings, together
with an increase of microhardness and fracture toughness. 相似文献
262.
Edoardo Ruggeri Miguel Anaya Krzysztof Gakowski Graud Delport Felix Utama Kosasih Anna Abfalterer Sebastian Mackowski Caterina Ducati Samuel D. Stranks 《Advanced materials (Deerfield Beach, Fla.)》2019,31(51)
Halide perovskites are emerging as valid alternatives to conventional photovoltaic active materials owing to their low cost and high device performances. This material family also shows exceptional tunability of properties by varying chemical components, crystal structure, and dimensionality, providing a unique set of building blocks for new structures. Here, highly stable self‐assembled lead–tin perovskite heterostructures formed between low‐bandgap 3D and higher‐bandgap 2D components are demonstrated. A combination of surface‐sensitive X‐ray diffraction, spatially resolved photoluminescence, and electron microscopy measurements is used to reveal that microstructural heterojunctions form between high‐bandgap 2D surface crystallites and lower‐bandgap 3D domains. Furthermore, in situ X‐ray diffraction measurements are used during film formation to show that an ammonium thiocyanate additive delays formation of the 3D component and thus provides a tunable lever to substantially increase the fraction of 2D surface crystallites. These novel heterostructures will find use in bottom cells for stable tandem photovoltaics with a surface 2D layer passivating the 3D material, or in energy‐transfer devices requiring controlled energy flow from localized surface crystallites to the bulk. 相似文献
263.
Maddox-Hyttel C Nöckler K Pozio E Vallée I Boireau P 《Journal of food protection》2007,70(12):2896-2899
Pepsin powder constitutes a health risk, potentially causing severe allergic reactions to those handling the chemical. A fluid pepsin formulation was produced and tested, first in a preliminary study and then in a ring trial encompassing four European National Reference Laboratories (NRLs). The purpose of each trial was to ascertain and compare the action of pepsin powder with that of the pepsin fluid for digesting meat and liberating encapsulated Trichinella spiralis larvae for subsequent counting. The quality of digestion was furthermore evaluated by assessing the visibility through the digestion fluid and the amount of debris remaining after digestion. For the ring trial, at each laboratory 20 blinded replicate 100-g samples of pork meat containing a known number of encapsulated T. spiralis larvae (0 to 30) were digested by the magnetic stirrer method using either the standard pepsin powder (10 samples) or the pepsin fluid (10 samples). With an average recovery rate of 70 to 80%, all NRLs found the pepsin fluid and pepsin powder to be equally effective. The NRLs also found no difference between the two pepsin formulations with regard to debris remnants or visibility through the digestion fluid. The use of pepsin fluid may therefore constitute an improvement of the digestion procedure for the analysts involved. 相似文献
264.
Rigid body water impact-experimental tests and numerical simulations using the SPH method 总被引:1,自引:0,他引:1
Marco AnghileriLuigi-Maria L. Castelletti Edoardo FrancesconiAndrea Milanese Michele Pittofrati 《International Journal of Impact Engineering》2011,38(4):141-151
Statistics show that water impact of an aircraft in emergency is likely to have tragic consequences and therefore new researches on this topic are recommendable. In 2005, the GARTEUR AG15 was established to improve the SPH method for application to helicopter ditching. As a contribution, water impact drop tests using rigid bodies were performed at the Politecnico di Milano LAST Crash Lab to collect data and validate the numerical models. During the tests, impact decelerations were measured and suitably pressure transducers were developed to measure the impact pressures. Numerical simulations were carried out by adopting the SPH method to model the fluid region. A close experimental-numerical correlation was obtained. Findings are reported and guidelines for further investigations are proposed. 相似文献
265.
A simplified method for the assessment of bending moment resistance for reinforced concrete (RC) members with circular cross-sections is presented. In the proposed method longitudinal rebars arrangement is replaced with a thin steel ring equivalent to the steel total area; moreover, according to modern codes, simplified stress-strain relationships for concrete and reinforcing steel are used.The performed analyses demonstrate that the value of flexural capacity determined by the proposed approach, is very close to the results obtained by applying rigorous methods based on analytical and numerical algorithms.The study also proves that in members subjected to bending moment without axial load, the flexural strength depends on the geometry of the section (i.e. radius and concrete cover) and on mechanical ratio of steel reinforcement by a very simple formula. 相似文献
266.
Oscar Belotti Edoardo Bonizzoni Franco Maloberti 《Analog Integrated Circuits and Signal Processing》2012,73(1):255-264
A technique for the exact design of the noise transfer function of Continuous-Time (CT) Sigma-Delta modulators with arbitrary and multiple DAC responses and real op-amps is here presented. The approach, that presupposes linear behavior of active blocks, produces a CT modulator with the same noise shaping as its Discrete-Time counterpart. The method operates entirely in the time domain and accounts for non-idealities of real implementations such as finite gain and bandwidth of integrators. The procedure can be effectively implemented with circuit simulators to allow the exact design with transistor level blocks. A design example on a third-order scheme confirms the effectiveness of the method. 相似文献
267.
Edoardo Basilico Sabrina Marcelin Remy Mingant Jean Kittel Marion Fregonese Francois Ropital 《工业材料与腐蚀》2021,72(7):1152-1167
This study summarizes the chemical effects that can occur during the corrosion process of carbon steel in a CO2-saturated aqueous environment. Particularly, it focuses more on the results that small chemical contaminations in the environment have on the corrosion process. Underground waters present complex chemistry with several different dissolved ions (chlorides, carbonates) even in high concentrations that impact substantially the corrosion rates of these materials. Moreover, gas impurities present in the gas mixture, such as oxygen in carbon capture and storage applications, constitute a supplementary form of significant contamination in the CO2-saturated aqueous environment. In particular, the effect on both electrochemical reactions and corrosion product layer is examined for several chemical species that are commonly present either in the gas mixture or in underground waters. 相似文献
268.
269.
270.
Sean Walker Ushnik Mukherjee Michael Fowler Itai Arbiv Edoardo Lazzaroni 《国际能源研究杂志》2016,40(14):1925-1934
Hydrogen is an important commodity in the processing of intermediate bitumen products into a finished petroleum product and for upgrading bitumen into synthetic crude. With the continued extraction of bitumen‐rich material from Alberta's oil sands project, there is an opportunity to reduce the greenhouse gas emissions of upgrading and refining operations by using electrolytically produced hydrogen in place of hydrogen produced by steam methane reformation. Recently, a bitumen upgrading facility had been proposed for the city of Sarnia, Ontario because of its pre‐existing petroleum processing infrastructure. Using the Ontario electrical system, which has a lower emissions factor than Alberta, the use of electrolytic hydrogen could result in a significant reduction of greenhouse gasses. In this paper, the objective is to determine an optimal system configuration for reducing greenhouse gas emissions while maintaining a low system cost. The analysis is performed with General Algebraic Modelling System tool, a mixed‐integer linear optimization in addition to a simple model in Visual Basic. For each case, an economic and environmental analysis is performed including the use of cap‐and‐trade values for the price of carbon emissions, which are applied to determine the overall economic impact of the emissions reductions. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献