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81.
82.
采用吸收/吸附-催化有氧分解耦合工艺净化合成氨及尿素生产过程中产生的含氨废气。介绍了净化合成氨弛放气的工程示范装置的工艺操作条件、工艺流程及运行效果。氨含量约3%的弛放气经过离子液吸收塔处理后,气体中的氨平均浓度降到45×10-6以下,再经4级蒸馏后,回收氨的浓度可达95%;氢氨回收膜分离装置含少量氨的工艺尾气经催化反应器处理后,排放氨浓度小于1.4×10-6;弛放气中氨的净化率达到99.99%。 相似文献
83.
Numerical investigation on the number of active surface sites of carbon catalysts in the decomposition of methane 下载免费PDF全文
Maryam Younessi‐Sinaki Feridun Hamdullahpur 《American Institute of Chemical Engineers》2014,60(6):2228-2234
The number of active sites on the surface of carbon catalysts is an important factor in determining their activity in the decomposition of methane. Although several studies have been performed to identify the nature of these sites, no method has been established to estimate their number. A method is presented to estimate this value, and its effect on hydrogen production is evaluated, along with that of temperature and residence time. For this purpose, the thermocatalytic decomposition of methane is modeled with the inclusion of the number of active sites of the catalyst in the kinetics. The results of the model indicate the high influence of variations of small residence times in this process, and the reduction of this effect at high temperatures. Also, the effect of the number of surface sites is shown to be more prominent at low residence times and temperatures. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2228–2234, 2014 相似文献
84.
Formic acid decomposition on Au catalysts: DFT,microkinetic modeling,and reaction kinetics experiments 下载免费PDF全文
Ronald Carrasquillo‐Flores Ana C. Alba‐Rubio James A. Dumesic Manos Mavrikakis 《American Institute of Chemical Engineers》2014,60(4):1303-1319
A combined theoretical and experimental approach is presented that uses a comprehensive mean‐field microkinetic model, reaction kinetics experiments, and scanning transmission electron microscopy imaging to unravel the reaction mechanism and provide insights into the nature of active sites for formic acid (HCOOH) decomposition on Au/SiC catalysts. All input parameters for the microkinetic model are derived from periodic, self‐consistent, generalized gradient approximation (GGA‐PW91) density functional theory calculations on the Au(111), Au(100), and Au(211) surfaces and are subsequently adjusted to describe the experimental HCOOH decomposition rate and selectivity data. It is shown that the HCOOH decomposition follows the formate (HCOO) mediated path, with 100% selectivity toward the dehydrogenation products (CO2 + H2) under all reaction conditions. An analysis of the kinetic parameters suggests that an Au surface in which the coordination number of surface Au atoms is ≤4 may provide a better model for the active site of HCOOH decomposition on these specific supported Au catalysts. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1303–1319, 2014 相似文献
85.
Steam reforming of ethanol over skeletal Ni‐based catalysts: A temperature programmed desorption and kinetic study 下载免费PDF全文
Chengxi Zhang Shuirong Li Gaowei Wu Zhiqi Huang Zhiping Han Tuo Wang Jinlong Gong 《American Institute of Chemical Engineers》2014,60(2):635-644
An investigation on reaction scheme and kinetics for ethanol steam reforming on skeletal nickel catalysts is described. Catalytic activity of skeletal nickel catalyst for low‐temperature steam reforming has been studied in detail, and the reasons for its high reactivity for H2 production are attained by probe reactions. Higher activity of water gas shift reaction and methanation contributes to the low CO selectivity. Cu and Pt addition can promote WGSR and suppress methanation, and, thus, improve H2 production. A reaction scheme on skeletal nickel catalyst has been proposed through temperature programmed reaction spectroscopy experiments. An Eley‐Rideal model is put forward for kinetic studies, which contains three surface reactions: ethanol decomposition, water gas shift reaction, and methane steam reforming reaction. The kinetics was studied at 300–400°C using a randomized algorithms method and a least‐squares method to solve the differential equations and fit the experimental data; the goodness of fit obtained with this model is above 0.95. The activation energies for the ethanol decomposition, methane steam reforming, and water gas shift reaction are 187.7 kJ/mol, 138.5 kJ/mol and 52.8 kJ/mol, respectively. Thus, ethanol decomposition was determined to be the rate determining reaction of ethanol steam reforming on skeletal nickel catalysts. © 2013 American Institute of Chemical Engineers AIChE J 60: 635–644, 2014 相似文献
86.
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以4-[3,5-双(4-氨基苯氧基)苯氧基]邻苯二甲腈和3,3′,4,4′-联苯四甲酸二酐为原料,经聚酰胺酸热酰亚胺化制备含氰基的聚酰亚胺(CN-BP-PI)薄膜。采用傅里叶变换红外光谱、热重分析、差示扫描量热法对CN-BP-PI薄膜进行了分析。采用动态热重法研究了CN-BP-PI的分解动力学,用积分法结合常见固相热分解反应动力学函数来判断热分解的动力学函数。由Ozawa,KAS,Kissinger,Achar,Coats-Redfern,MacCallum-Tanner,van Krevelen方程求热分解反应的动力学参数。转化率为0.2~0.8时所得CN-BP-PI在氮气中热分解反应的表观活化能为119.68~215.61 kJ/mol,平均活化能为136.35 kJ/mol,指前因子平均值为8.52×107 s-1。 相似文献
89.
In this paper a recursive state-space model identification method is proposed for non-uniformly sampled systems in industrial applications. Two cases for measuring all states and only output(s) of such... 相似文献
90.
羧酸盐配合物具有非常广泛的用途,热稳定性作为其非常重要的一种性质而被深入研究。本文对稀土、碱土和过渡金属羧酸盐配合物的热分解反应过程,以及芳香族羧酸盐配合物的热分解过程的动力学分析方面的研究进展进行了综述,以期为该类物质的实际应用提供更全面的参考数据。 相似文献