全文获取类型
收费全文 | 2671篇 |
免费 | 53篇 |
国内免费 | 65篇 |
专业分类
电工技术 | 22篇 |
综合类 | 89篇 |
化学工业 | 1425篇 |
金属工艺 | 135篇 |
机械仪表 | 48篇 |
建筑科学 | 50篇 |
矿业工程 | 37篇 |
能源动力 | 316篇 |
轻工业 | 110篇 |
水利工程 | 8篇 |
石油天然气 | 84篇 |
武器工业 | 9篇 |
无线电 | 36篇 |
一般工业技术 | 186篇 |
冶金工业 | 54篇 |
原子能技术 | 56篇 |
自动化技术 | 124篇 |
出版年
2024年 | 5篇 |
2023年 | 37篇 |
2022年 | 55篇 |
2021年 | 74篇 |
2020年 | 76篇 |
2019年 | 70篇 |
2018年 | 63篇 |
2017年 | 56篇 |
2016年 | 46篇 |
2015年 | 44篇 |
2014年 | 119篇 |
2013年 | 166篇 |
2012年 | 98篇 |
2011年 | 184篇 |
2010年 | 129篇 |
2009年 | 139篇 |
2008年 | 128篇 |
2007年 | 129篇 |
2006年 | 121篇 |
2005年 | 114篇 |
2004年 | 105篇 |
2003年 | 119篇 |
2002年 | 98篇 |
2001年 | 69篇 |
2000年 | 56篇 |
1999年 | 69篇 |
1998年 | 67篇 |
1997年 | 53篇 |
1996年 | 52篇 |
1995年 | 59篇 |
1994年 | 38篇 |
1993年 | 41篇 |
1992年 | 27篇 |
1991年 | 23篇 |
1990年 | 15篇 |
1989年 | 9篇 |
1988年 | 11篇 |
1987年 | 10篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1966年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有2789条查询结果,搜索用时 31 毫秒
1.
对己二腈工业反应器提出了两釜串联带回流的模型,通过模拟计算得出模型的级间返混系数 f=6的结论。该模型能较好地预测工业反应器中物料组分浓度变化和气、液两相的流动特性;指出了现工业反应器的鼓泡中和段体积偏小是造成己二酸浓度偏高的关键;提出了可以通过增加串连一个鼓泡预反应段的改造方案,能有效地降低己二酸的浓度,从7%降至4%左右,从而能较好地减缓腐蚀和结焦。 相似文献
2.
3.
《Drying Technology》2007,25(6):971-983
This article reviews developments in the simulations of spray dryer behavior, including the challenges in modeling the complex flow patterns inside the equipment, which are often highly transient and three-dimensional in nature. There appears to be considerable scope for using CFD simulations for investigating methods to reduce the rates of wall deposition and of thermal degradation for particles by modifying the air flow patterns in the chamber through small changes in the air inlet geometry. Challenges include building particle drying kinetics and reaction processes, as well as agglomeration behavior, into these simulations. The numerical simulations should be valuable supplements to pilot-scale testing, enabling more extensive and accurate optimization to be carried out than hitherto possible. New understanding of reaction processes and materials science, in combination with recent knowledge of the application of CFD to these problems, may enable new engineered powder products to be developed from the one-step spray-drying process. 相似文献
4.
Theoretical predictions using a modified radical species ternary diagram for C–H–O system indicate that addition of sulfur expands the C–H–O gas phase compositional window for diamond deposition. Sulfur addition to no-growth domain increases the carbon super-saturation by binding the oxygen and the addition of sulfur to the non-diamond domain reduces the heavy carbon super-saturation by decreasing CnHm species concentration in the gas phase. The overall effect of sulfur addition to gas phase mixtures is characterized as that of oxygen addition to the C–H system, i.e. expansion of the compositional window over which diamond can be deposited from the gas phase. In addition, the increasing sulfur concentration to diamond domain feed gases beyond 2000 ppm did not affect the steady state gas phase composition but the quality of diamond was reduced. 相似文献
5.
Pierluigi Guerrini De LucaClaudio Scali 《Chemical engineering science》2002,57(11):2077-2087
Applicability of different temperature oscillation calorimetry algorithms, previously proposed in the literature, for the evaluation of the heat transfer coefficient during the course of the reaction, is analysed by referring to the experimental data from a methyl methacrylate polymerisation reactor.Results are coincident in the nominal case (no errors on data), while differences appear in the elaboration of real data. The effect of uncertainty in the experimental data has been simulated in terms of error on the amplitude and on the phase of reactor and jacket temperature profiles.This approach allows to indicate algorithms having the best robustness properties and to give an explanation of phase errors in terms of a lumped parameter which accounts for different phenomena, not included in the basic hypotheses of the method. Based on this observation, a procedure to eliminate this source of errors from experimental data is proposed for the more general algorithm presented to handle oscillating temperature profiles generated by different techniques. 相似文献
6.
Dmitry Yu. Murzin 《Chemical engineering science》2002,57(8):1299-1306
Several aspects of heterogeneous catalytic kinetics over induced nonuniform surfaces are considered. The reaction mechanism is thought to occur through a surface collision of species, adsorbed on two distinct surface sites, which display nonuniform behavior. The expressions for rates of elementary reactions have been deduced within the framework of the surface electronic gas model, which accounts for the case of inhomogeneous surface. Equations for catalyst activity in the range of medium coverage have been derived and compared with the power-law model. 相似文献
7.
钨系延期药预点火反应机理研究 总被引:7,自引:3,他引:4
通过程控升温模拟点火条件,根据DSC图谱分析,找出主要反应区的温度范围。研究结果表明,钨系延期药预点火反应是一个真正的固-固反应。 相似文献
8.
Ana Mafalda RibeiroJosé Miguel Loureiro 《Chemical engineering science》2002,57(9):1621-1626
The system ASC carbon filter/cyanogen chloride was studied by simulation. Three filter configurations and several models, taking into account Langmuir adsorption and second-order reaction between the adsorbed toxic vapour and the active metal on the surface, were developed.The effects of axial dispersion, number of reaction units, film mass transfer units and intraparticle mass transfer resistance on the breakthrough time were studied.Simulation results show that a complex model should be used in order to predict with reasonable accuracy the protection imparted by these filters. 相似文献
9.
10.