全文获取类型
收费全文 | 3914篇 |
免费 | 333篇 |
国内免费 | 82篇 |
专业分类
电工技术 | 181篇 |
综合类 | 132篇 |
化学工业 | 2239篇 |
金属工艺 | 19篇 |
机械仪表 | 27篇 |
建筑科学 | 114篇 |
矿业工程 | 219篇 |
能源动力 | 1023篇 |
轻工业 | 30篇 |
水利工程 | 1篇 |
石油天然气 | 166篇 |
武器工业 | 1篇 |
无线电 | 5篇 |
一般工业技术 | 41篇 |
冶金工业 | 107篇 |
原子能技术 | 4篇 |
自动化技术 | 20篇 |
出版年
2024年 | 5篇 |
2023年 | 43篇 |
2022年 | 101篇 |
2021年 | 109篇 |
2020年 | 125篇 |
2019年 | 138篇 |
2018年 | 98篇 |
2017年 | 96篇 |
2016年 | 126篇 |
2015年 | 124篇 |
2014年 | 252篇 |
2013年 | 259篇 |
2012年 | 297篇 |
2011年 | 334篇 |
2010年 | 251篇 |
2009年 | 244篇 |
2008年 | 168篇 |
2007年 | 247篇 |
2006年 | 177篇 |
2005年 | 157篇 |
2004年 | 144篇 |
2003年 | 147篇 |
2002年 | 76篇 |
2001年 | 79篇 |
2000年 | 86篇 |
1999年 | 55篇 |
1998年 | 66篇 |
1997年 | 34篇 |
1996年 | 46篇 |
1995年 | 28篇 |
1994年 | 29篇 |
1993年 | 18篇 |
1992年 | 18篇 |
1991年 | 13篇 |
1990年 | 9篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 11篇 |
1986年 | 3篇 |
1985年 | 26篇 |
1984年 | 21篇 |
1983年 | 36篇 |
1982年 | 10篇 |
1980年 | 5篇 |
1977年 | 1篇 |
1951年 | 6篇 |
排序方式: 共有4329条查询结果,搜索用时 15 毫秒
1.
Ir.H.E.M. Stassen 《Renewable Energy》1994,5(5-8)
Within the European Community, the interest in energy generation from biomass and waste is increasing. A brief overview is given of several thermal conversion technologies, of biomass production and waste availability in the Netherlands. Based on this, the possibilities for energy generation from biomass and waste in the Netherlands are evaluated. 相似文献
2.
Trace element evaporation during coal gasification based on a thermodynamic equilibrium calculation approach 总被引:1,自引:0,他引:1
《Fuel》2003,82(2):137-145
Thermodynamic equilibrium calculations using the HSC-Chemistry program were performed to determine the distribution and mode of occurrence of potentially toxic and corrosive trace elements in gases from coal gasification processes. The influence of temperature, pressure and gas atmospheres on equilibrium composition was evaluated. In these reducing conditions, the behaviour of the trace elements is complex, but some form of organization can be attempted. Elements were classified into three groups. Group A includes those elements that, according to thermodynamic data at equilibrium, could probably be condensed in coal gasification. Mn is classified in this group. Group B contains those elements that could be totally or partially in gas phase in gas cleaning conditions, and can be divided into two subgroups, depending on whether the cleaning conditions are hot or cold. Co, Be, Sb, As, Cd, Pb, Zn, Ni, V, Cr are elements in this group. Group C contains those elements that could be totally in gas phase in all the possible conditions, including flue gas emissions. Se, Hg and B are the elements that make up this group. 相似文献
4.
A simple treatment for obtaining the solution of single isothermal gas-solid non-catalytic reactions is presented. The model is formulated under a local volumetric approach and permits to incorporate non-linear chemical kinetics and the change in porous structure during conversion. The methodology developed in this work is based on the quantize method for decoupling the solid and gas equations and on perturbation and matching techniques for approximating the gas conservation equation. With this strategy, the calculation of gas concentration and solid conversion at any time and position are reduced to the solution of two coupled algebraic equations. The model compares favourably with the exact (numerical) solution for a variety of cases. This procedure provides an effective and general tool for obtaining the solution of gas-solid reactions with minor calculations. 相似文献
5.
A. Demoz C. Khulbe C. Fairbridge S. Petrovic 《Journal of Applied Electrochemistry》2008,38(6):845-851
Hydrogen is among the emerging energy vectors that are being developed to replace nonrenewable hydrocarbon energy sources.
The preferred method to produce hydrogen without generating greenhouse gases is the electrolysis of water using renewable
energy. The reduction of energy during the water electrolysis process is a desirable goal regardless of the source of electric
power. Similar to ferrous/ferric mediation, iodide can be used as a mediator in the electrolysis of an acidic suspension of
coke or coal. The iodide ion is oxidized at a far lower anodic potential than the alternative oxygen evolution reaction. This
reduces the cell electrolysis voltage and, consequently, reduces electricity use. The iodide consumed at the anode is continuously
regenerated by chemical reaction with the coke/coal in suspension. 相似文献
6.
The performance of a venturi scrubber in the removal of tar from gas in updraft gasification has been studied. The gasifier has been operated with a husk feed rate of 1.6 × 10?4 kg/s. The venturi scrubber has been operated at a superficial gas velocity of 56.4 m/s at the throat. A wide variety of scrubbing liquids having surface tensions ranging from 0.026 to 0.072 N/m have been used. The Qg/Ql, has been varied in the range of 1000–8000. The tar separation efficiency η has been found to vary from 51 to 98.5%. A mathematical model, assuming steady-state operation, has been developed considering very high pseudosolubility of tar in the scrubbing liquids. The predicted values of η have been compared with experimental results. The model satisfactorily explains the tar removal efficiency of the venturi for Qg/Ql values ranging from 4000 to 8000 for all scrubbing liquids. The following correlation has been developed for predicting venturi scrubber efficiency: . 相似文献
7.
Phosphogypsum (PG) is a solid waste produced in the wet process of producing phosphoric acid.Lignite is a kind of promising chemical raw material.However,the high sulfur of lignite limits the utilization of lig-nite as a resource.Based on fluidized bed experiments,the optimal reaction conditions for the production syngas by lignite chemical looping gasification (CLG) with PG as oxygen carrier were studied.The study found that the optimal reaction temperature should not exceed 1123 K;the mole ratio of water vapor to lignite should be about 0.2;the mole ratio of PG oxygen carrier to lignite should be about 0.6.Meanwhile,commercial software Comsol was used to establish a fuel reaction kinetics model.Through computational fluid dynamics (CFD) numerical simulation,the process of reaction in fluidized bed were well captured.The model was based on a two-fluid model and coupled mass transfer,heat transfer and chemical reac-tions.This study showed that the fluidized bed presents a flow structure in which gas and solid coexist.There was a high temperature zone in the middle and lower parts of the fluidized bed.It could be seen from the results of the flow field simulated that the fluidized bed was beneficial to the progress of the gasification reaction. 相似文献
8.
An examination of the influence of pressure and heating rate on the thermoplastic properties of a weakly coking coal and of coal with various pitch-like additives was carried out using a high pressure dilatometer. Pressure up to 4 MPa markedly increased the swelling properties and increased the plastic range by decreasing the softening temperature, but the effects of pressure were strongly influenced by rate of heating with high heating rates enhancing the effects. Additions of tar or pitch also enhanced swelling at low pressure. The solid carbonization residues from the dilatometer were examined by polarized light microscopy to determine the content and composition of optically anisotropic species. The anisotropic content was increased by increases in pressure and heating rate and pitch additives enhanced the anisotropic content, especially at low pressure, without affecting the composition of the anisotropy. No direct correlations exist between the dilatometric parameters and the optical anisotropy but their dependence on the conditions emphasizes that when considering high pressure gasification of coal, it is necessary to obtain data under appropriate conditions. 相似文献
9.
10.
大化肥煤代油CO耐硫变换工艺流程的设计 总被引:2,自引:0,他引:2
分析石脑油制氨装置改扩建为水煤浆制氨装置CO耐硫变换工艺的特点,具体阐述其工艺流程优化设计中需考虑的主要技术问题。 相似文献