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941.
用己二胺、己二酸及双功能团的氯化螺环磷酸酯经界面缩合制得含磷尼龙 66。燃烧试验表明 ,该产物具有难燃、易自熄、不产生浓烟和熔滴等特性。 相似文献
942.
943.
Stationary regimes of combustion in an energy-conversion system are studied, and its efficiency is estimated. This system
is a channel with thermoelectric converters embedded into the channel walls and with combustion of premixed gases inside the
channel. For the maximum efficiency of energy conversion in a small-size device to be reached, the properties of thermoelectric
materials, the device geometry, and other parameters have to be correlated with the internal structure of the flame. In particular,
the efficiency of energy conversion in a small-size device can be higher than that in a similar large-size device, and the
maximum efficiency is reached near the flammability limits.
__________
Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 4, pp. 15–22, July–August, 2007. 相似文献
944.
An experimental investigation was conducted to explore the rate of flame spread over an unconsolidated porous bed of sand wetted with 2-propanol under a range of operating conditions. Video cinematography was employed to determine the rate of flame spread and characterise the combustion behaviour of the system. The rate of flame spread strongly correlated with: (i) the ratio of fuel volume to the weight of the sand bed, referred to as FR, and (ii) the flame initiation delay, referred to as FID. The rates of flame spread associated with no initiation delay cases were found to rise with increasing FR while for cases associated with any given flame initiation delay the rate of flame spread was found to decrease with increasing FR. In addition, the rate of change in flame spread was observed to be different for beds containing finer particles in comparison to those containing coarser ones. 相似文献
945.
Cristina Formicola Anna De Fenzo Mauro Zarrelli Michele Giordano Vincenza Antonucci 《Polymer International》2011,60(2):304-311
Smoke is considered to be the main hazard of fires involving epoxy resins but its production depends on many variables, principally the chemical character and the burning rate of the polymer plus the availability of oxygen. The work reported aimed to study the smoke suppressant effect and flammability performance of zinc‐based compounds (FR system) in epoxy matrix composites used in the aerospace and aeronautical industry. The flammability performance of neat and FR‐loaded systems was screened using microcombustion calorimetry, while smoke generation, in terms of carbon monoxide (CO) and carbon dioxide (CO2) production, was analysed under dynamic conditions using cone calorimetry. Final results indicate that the dispersion of zinc borate and zinc hydroxystannate (ZHS) into epoxy matrices leads to a significant variation in flame retardant properties reducing both total heat release by about 25 and 30%, respectively, and heat release capacity by about 30 and 50%, respectively. The system containing ZHS shows an enhancement in all smoke suppressant properties; both tin compounds (zinc stannate (ZS) and ZHS) give a reduction of CO2/CO ratio from 41 to 25 for ZS and from 41 to 36 for ZHS compared to neat matrix. Copyright © 2010 Society of Chemical Industry 相似文献
946.
947.
Karthik Kashinath Santosh Hemchandra Matthew P. Juniper 《Combustion and Flame》2013,160(12):2856-2865
When a premixed flame is placed within a duct, acoustic waves induce velocity perturbations at the flame’s base. These travel down the flame, distorting its surface and modulating its heat release. This can induce self-sustained thermoacoustic oscillations. Although the phase speed of these perturbations is often assumed to equal the mean flow speed, experiments conducted in other studies and Direct Numerical Simulation (DNS) conducted in this study show that it varies with the acoustic frequency. In this paper, we examine how these variations affect the nonlinear thermoacoustic behaviour. We model the heat release with a nonlinear kinematic G-equation, in which the velocity perturbation is modelled on DNS results. The acoustics are governed by linearised momentum and energy equations. We calculate the flame describing function (FDF) using harmonic forcing at several frequencies and amplitudes. Then we calculate thermoacoustic limit cycles and explain their existence and stability by examining the amplitude-dependence of the gain and phase of the FDF. We find that, when the phase speed equals the mean flow speed, the system has only one stable state. When the phase speed does not equal the mean flow speed, however, the system supports multiple limit cycles because the phase of the FDF changes significantly with oscillation amplitude. This shows that the phase speed of velocity perturbations has a strong influence on the nonlinear thermoacoustic behaviour of ducted premixed flames. 相似文献
948.
This article presents a novel investigation on the Mo/Mg/Ni/O catalysts (Nmm‐cats) with which the noncharring polyolefins are basically transferred to the charring polymers under forced flaming conditions and the flame retardancy of polyolefins is improved dramatically. The results of model charring experiments show that when appropriate Mo/Mg/Ni molar ratio is adopted and only 3% Nmm‐cats is blended, the Nmm‐cats belong to high‐efficient charring catalysts that can deposit 56 and 64 wt % of volatile products in‐situ from linear low‐density polyethylene (LLDPE) and polypropylene (PP), respectively. The charring properties are characterized by scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy; and the char‐forming mechanisms are analyzed by wide‐angle X‐ray diffraction experiment. The improvement in flammability properties for LLDPE and PP is demonstrated by using a cone calorimeter. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
949.
Downstream interactions between lean premixed flames with mutually different fuels of (50% H2 + 50% CO) and CH4 are numerically investigated particularly on and near lean extinction limits in order to provide fundamental database for the design of cofiring burners with hydrocarbon and syngas under a retrofit concept. In the current study the anomalous combination of lean premixed flames is provided such that even a weaker CH4-air flame temperature is higher than a stronger syngas-air flame temperature, and, based on a deficient reactant concept, the effective Lewis numbers Leeff ≈ 1 for lean premixed (50% H2 + 50% CO)-air mixture and LeD < 1 for CH4-air mixture. It is found that the interaction characteristics between lean premixed (50% H2 + 50% CO)-air and CH4-air flames are quite different from those between the same hydrocarbon flames. The lean extinction boundaries are of slanted shape, thereby indicating strong interactions. The upper extinction boundaries have negative flame speeds while the lower extinction boundaries have both negative and positive flame speeds. The results also show that the flame interaction characteristics do not follow the general tendency of Lewis number, which has been well described in interactions between the same hydrocarbon flames, but have the strong dependency of direct interaction factors such as flame temperature, the distance between two flames, and radical-sharing. Importance of chain carrier radicals such as H is also addressed in the downstream interactions between lean premixed (50% H2 + 50% CO)-air and CH4-air flames. 相似文献
950.
This paper mainly deals with flame retardance of a silk fabric treated with a vinyl phosphate dimethyl 2‐(methacryloyloxyethyl) phosphate (DMMEP) onto silk fabric by a graft copolymerization technique. This paper also explores the relationship between limiting oxygen index (LOI) and weight gain of DMMEP treated silk fabric. The paper also investigates the whiteness, handle, tensile strength and laundering durability of treated silk fabric. Microscale combustion calorimetry (MCC) is applied to test the heat release rate of silk fabric. Thermal gravimetric analysis (TG) and differential thermal analysis (DTA) are carried out to investigate the thermal decomposition behavior of DMMEP treated silk fabric. The kinetic parameters, activation energy and pre‐exponential factor are determined using the Kissenger method. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献