全文获取类型
收费全文 | 5761篇 |
免费 | 198篇 |
国内免费 | 12篇 |
专业分类
电工技术 | 62篇 |
综合类 | 1篇 |
化学工业 | 1140篇 |
金属工艺 | 100篇 |
机械仪表 | 90篇 |
建筑科学 | 324篇 |
矿业工程 | 21篇 |
能源动力 | 195篇 |
轻工业 | 539篇 |
水利工程 | 49篇 |
石油天然气 | 42篇 |
武器工业 | 1篇 |
无线电 | 324篇 |
一般工业技术 | 925篇 |
冶金工业 | 1114篇 |
原子能技术 | 30篇 |
自动化技术 | 1014篇 |
出版年
2023年 | 34篇 |
2022年 | 59篇 |
2021年 | 90篇 |
2020年 | 85篇 |
2019年 | 76篇 |
2018年 | 103篇 |
2017年 | 84篇 |
2016年 | 138篇 |
2015年 | 102篇 |
2014年 | 181篇 |
2013年 | 377篇 |
2012年 | 269篇 |
2011年 | 351篇 |
2010年 | 251篇 |
2009年 | 218篇 |
2008年 | 286篇 |
2007年 | 257篇 |
2006年 | 213篇 |
2005年 | 209篇 |
2004年 | 154篇 |
2003年 | 146篇 |
2002年 | 147篇 |
2001年 | 87篇 |
2000年 | 86篇 |
1999年 | 94篇 |
1998年 | 135篇 |
1997年 | 130篇 |
1996年 | 88篇 |
1995年 | 96篇 |
1994年 | 72篇 |
1993年 | 89篇 |
1992年 | 89篇 |
1991年 | 55篇 |
1990年 | 58篇 |
1989年 | 59篇 |
1988年 | 51篇 |
1987年 | 52篇 |
1986年 | 60篇 |
1985年 | 74篇 |
1984年 | 71篇 |
1983年 | 76篇 |
1982年 | 58篇 |
1981年 | 51篇 |
1980年 | 52篇 |
1979年 | 76篇 |
1978年 | 56篇 |
1977年 | 54篇 |
1976年 | 45篇 |
1975年 | 44篇 |
1973年 | 28篇 |
排序方式: 共有5971条查询结果,搜索用时 15 毫秒
21.
22.
Liang-Yu Chen Gary W Hunter Philip G Neudeck Dak Knight 《Solid-state electronics》1998,42(12):2209-2214
The surface and interface properties of Pd0.9Cr0.1/SiC Schottky diode gas sensors both before and after annealing are investigated using Auger electron spectroscopy (AES), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). At room temperature the alloy reacted with SiC and formed PdxSi only in a very narrow interfacial region. After annealing for 250 h at 425°C, the surface of the Schottky contact area has much less silicon and carbon contamination than that found on the surface of an annealed Pd/SiC structure. Palladium silicides (PdxSi) formed at a broadened interface after annealing, but a significant layer of alloy film is still free of silicon and carbon. The chromium concentration with respect to palladium is quite uniform down to the deep interface region. A stable catalytic surface and a clean layer of Pd0.9Cr0.1 film are likely responsible for significantly improved device sensitivity. 相似文献
23.
The authors highlight several possible ways in which the construction industry could lower present emissions of the greenhouse gas, carbon dioxide. It is an excellent discussion document and is recommended reading. 相似文献
24.
25.
Control of volatile organic compounds by an AC energizedferroelectric pellet reactor and a pulsed corona reactor 总被引:1,自引:0,他引:1
Yamamoto T. Ramanathan K. Lawless P.A. Ensor D.S. Newsome J.R. Plaks N. Ramsey G.H. 《Industry Applications, IEEE Transactions on》1992,28(3):528-534
Two laboratory-scale plasma reactors, an alternating current (AC) energized ferroelectric (high dielectric ceramic) packed bed reactor and a nanosecond pulsed corona reactor, were constructed. This study was done to develop baseline engineering data to demonstrate the feasibility of the application of plasma reactors to the destruction of various volatile organic compounds (VOCs) at PPM levels. Complete destruction was obtained for toluene. Conversions of methylene chloride at 95% and trichlorotrifluoroethane (known as CFC-113) at 67% were achieved for the plasma reactors used. The conversion was dependent on the mean electron energy in the reactor and was also related to how strongly halogen species were bonded with carbon 相似文献
26.
Mark S. Daskin Philip C. Jones 《Computer-Aided Civil and Infrastructure Engineering》1993,8(6):409-421
Abstract: Facility location and customer allocation problems are pervasive in industry and in the private sector. In this paper, we outline a new approach to solving these problems that avoids the need to resort to integer programming techniques. The approach exploits the mathematical structure of the problem as well as characteristics frequently found in applied location/allocation problems. Using this approach, large scale problems are readily solvable on personal computers. We illustrate the approach on a small example and provide computational results based on a real-world application of the technique. Extensions to include additional problem features are also discussed. 相似文献
27.
28.
Yan T Wong Norbert Dommel Philip Preston Luke E Hallum Torsten Lehmann Nigel H Lovell Gregg J Suaning 《IEEE transactions on neural systems and rehabilitation engineering》2007,15(3):425-434
A neurostimulator application-specific integrated circuit (ASIC) with scalable circuitry that can stimulate 14 channels, has been developed for an epi-retinal vision prosthesis. This ASIC was designed to allow seven identical units to be connected to control up to 98 channels, with the ability to stimulate 14 electrodes simultaneously. The neurostimulator forms part of a vision prosthesis, designed to restore vision to patients who have lost their sight due to retinal diseases such as retinitis pigmentosa and macular degeneration. For charge balance, the neurostimulator was designed to stimulate with current sources and sinks operating together, and with the ability to drive a hexagonal mosaic of electrodes to reduce the electrical crosstalk that occurs when multiple bipolar stimulation sites are active simultaneously. A hexagonal mosaic of electrodes surrounds each stimulation site and has been shown to effectively isolate each site, increasing the ability to inject localized independent charge into multiple regions simultaneously. 相似文献
29.
Amit Chourasia Steve Cutchin Yifeng Cui Reagan W Moore Kim Olsen Steven M Day J Bernard Minster Philip Maechling Thomas H Jordan 《Computer Graphics and Applications, IEEE》2007,27(5):28-34
This study focuses on the visualization of a series of large earthquake simulations collectively called TeraShake. The simulation series aims to assess the impact of San Andreas Fault earthquake scenarios in Southern California. We discuss the role of visualization in gaining scientific insight and aiding unexpected discoveries. 相似文献
30.
Noel D. Uri 《Applied Energy》1996,54(4):355-373
This study begins by asking whether fluctuations in the price of crude oil have affected agricultural employment in the USA. After reviewing previous assessments of the issue, the existence of an empirical relationship between agricultural employment and crude-oil price volatility is established using Granger causality. Subsequently, the nature of the relationship is estimated with the results suggesting that at least three full years are required before the measurable impacts of a percentage change in the real price of crude oil on the change in agricultural employment are exhausted. Finally, the structural stability of the functional relationship between the change in agricultural employment and the volatility of the price of crude oil, the percentage changes in expected net farm income, realized technological innovation, and the wage rate are examined. 相似文献