全文获取类型
收费全文 | 1973篇 |
免费 | 111篇 |
国内免费 | 104篇 |
专业分类
电工技术 | 120篇 |
综合类 | 160篇 |
化学工业 | 293篇 |
金属工艺 | 94篇 |
机械仪表 | 123篇 |
建筑科学 | 140篇 |
矿业工程 | 57篇 |
能源动力 | 398篇 |
轻工业 | 40篇 |
水利工程 | 42篇 |
石油天然气 | 46篇 |
武器工业 | 92篇 |
无线电 | 126篇 |
一般工业技术 | 187篇 |
冶金工业 | 68篇 |
原子能技术 | 27篇 |
自动化技术 | 175篇 |
出版年
2024年 | 2篇 |
2023年 | 22篇 |
2022年 | 59篇 |
2021年 | 50篇 |
2020年 | 55篇 |
2019年 | 53篇 |
2018年 | 39篇 |
2017年 | 59篇 |
2016年 | 55篇 |
2015年 | 63篇 |
2014年 | 149篇 |
2013年 | 106篇 |
2012年 | 104篇 |
2011年 | 134篇 |
2010年 | 117篇 |
2009年 | 125篇 |
2008年 | 100篇 |
2007年 | 122篇 |
2006年 | 102篇 |
2005年 | 84篇 |
2004年 | 73篇 |
2003年 | 87篇 |
2002年 | 60篇 |
2001年 | 47篇 |
2000年 | 47篇 |
1999年 | 50篇 |
1998年 | 30篇 |
1997年 | 32篇 |
1996年 | 19篇 |
1995年 | 20篇 |
1994年 | 18篇 |
1993年 | 20篇 |
1992年 | 12篇 |
1991年 | 13篇 |
1990年 | 15篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1965年 | 2篇 |
1962年 | 1篇 |
1961年 | 1篇 |
1959年 | 2篇 |
1958年 | 1篇 |
1956年 | 1篇 |
1955年 | 1篇 |
1954年 | 2篇 |
排序方式: 共有2188条查询结果,搜索用时 15 毫秒
1.
This paper investigates the catalytic ignition of the H2/O2/CO2 mixture on platinum in a stagnation flow at atmospheric pressure experimentally and numerically. We measure the ignition temperatures of the gas mixtures flowing towards resistively heated platinum with various composition ratios and various diluent gases of N2, Ar and CO2. Compared with N2 or Ar, the CO2 dilution shows higher ignition temperature by about 50 K, even at the same composition ratio. The ignition temperature increase is proportional to the dilution ratio. Through the numerical simulation, it is illustrated that higher ignition temperature is caused by the adsorption of CO2 and following dissociation on platinum surface, which was to date considered negligible in catalytic combustion. 相似文献
2.
以山西省河津市小梁乡为代表,研究了因建筑业的发展壮大而产生的社会经济空心化现象,分析了其形成原因,并提出了解决措施,以期引起大家对这一社会经济现象的关注,开展更深层次的研究。 相似文献
3.
本文介绍了磁电机点火系统的点火提前角测量原理。对点火系统的点火信号和触发信号进行采集、调理,再用单片机进行处理,最后用LabVIEW进行点火提前角数据存储和显示。 相似文献
4.
Reconstruction of a discontinuous function from a few fourier coefficients using bayesian estimation
Alex Solomonoff 《Journal of scientific computing》1995,10(1):29-80
The goal of this paper is the application of spectral methods to the numerical solution of conservation law equations. Spectral methods furnish estimates of the firstn Fourier coefficients of the solution. But since the solutions of conservation law equations can have discontinuities, the estimate of the solution by summing the firstn terms of the Fourier series will haveO(1/n) error, even if the Fourier coefficients are known to high accuracy. But if the solution could be accurately reconstructed from its Fourier coefficients, spectral methods could be used effectively in these problems. A method for doing this is to assume a probability distribution for functions. Functions which are smooth away from the discontinuity are assumed to be likely, and those which are not smooth away from the discontinuity are assumed to be unlikely. Then a reconstruction algorithm is chosen by minimizing the expected error over all algorithms. It is possible to put the smoothness assumptions mentioned earlier into an infinite-dimensional Gaussian probability distribution, and then the minimum-error algorithm is well-known and fairly simple to construct and apply. If the Fourier coefficients of the reconstructed function are known exactly, then this approach gives very good results. But when used with Fourier coefficients obtained from a spectral approximation to Burgers' equation, the results were much less impressive, probably because the coefficients were not known very accurately. It is possible to construct filters that reconstruct a function using Legendre or Chebyshev coefficients for information instead Fourier coefficients. It is found that the performance of these filters is similar to the Fourier case. 相似文献
5.
铁锈渣对氧气生产的危害 总被引:2,自引:0,他引:2
介绍铁锈、铁锈渣对氧气生产的危害 ,分析一起因铁锈、铁锈渣引起的氧压机着火而殃及氧气囊燃烧的事故 ,针对分析的原因提出预防措施。 相似文献
6.
分析了化工生产过程设备、管道中存在的各种“界面”现象及其影响,并提出相应对策。 相似文献
7.
8.
Microwave plasma is studied as an alternative to oil or gas fuel for ignition and stabilisation of burning of lean coal. The study is performed on an experimental set-up, which includes a burner with a microwave plasma generator, coal and air supply systems, and measurement equipment. Power and thermochemical characteristics of the coal-plasma interaction have been measured and analysed. The obtained results indicate an essential intensification of ignition and combustion processes in the microwave burner compared to those in conventional burners. In particular, it has been demonstrated that the microwave energy consumption is only about 10% of the required expenditure of oil or gas, measured in heat equivalent. A design of an industrial microwave-plasma burner is proposed. Prospects of such burner for applications at industrial boilers of power plants are discussed. 相似文献
9.
10.
Behavior of ignition and combustion of coal particle cluster under a quiescent condition was numerically simulated by solving balance equations of mass and enthalpy with combustion kinetic models of volatiles and char. Two-flame structure, one flame penetrating into the cluster and the other moving out of the cluster, was predicted during the combustion of coal particle cluster. Effects of radiative heat transfer, group number, ambient temperature, coal particle size, and oxygen concentration on ignition and combustion of coal particle clusters were also analyzed. Simulations indicated that the gas volume fraction of coal particle cluster increases with time after devolatilization. Gas velocity passing through the cluster surface varied significantly at volatile liberation. The ignition time delay was reduced with the increase of ambient temperature. The cluster devolatilization rate and char burning rate increased while the ignition time delay decreased with the increase of ambient oxygen concentration. 相似文献