全文获取类型
收费全文 | 9214篇 |
免费 | 788篇 |
国内免费 | 19篇 |
专业分类
电工技术 | 121篇 |
综合类 | 15篇 |
化学工业 | 2150篇 |
金属工艺 | 353篇 |
机械仪表 | 431篇 |
建筑科学 | 135篇 |
矿业工程 | 3篇 |
能源动力 | 348篇 |
轻工业 | 916篇 |
水利工程 | 35篇 |
石油天然气 | 8篇 |
武器工业 | 1篇 |
无线电 | 1522篇 |
一般工业技术 | 2106篇 |
冶金工业 | 922篇 |
原子能技术 | 83篇 |
自动化技术 | 872篇 |
出版年
2024年 | 11篇 |
2023年 | 134篇 |
2022年 | 196篇 |
2021年 | 330篇 |
2020年 | 231篇 |
2019年 | 232篇 |
2018年 | 315篇 |
2017年 | 337篇 |
2016年 | 407篇 |
2015年 | 354篇 |
2014年 | 462篇 |
2013年 | 639篇 |
2012年 | 649篇 |
2011年 | 841篇 |
2010年 | 588篇 |
2009年 | 550篇 |
2008年 | 448篇 |
2007年 | 390篇 |
2006年 | 323篇 |
2005年 | 259篇 |
2004年 | 263篇 |
2003年 | 221篇 |
2002年 | 165篇 |
2001年 | 153篇 |
2000年 | 157篇 |
1999年 | 148篇 |
1998年 | 341篇 |
1997年 | 189篇 |
1996年 | 147篇 |
1995年 | 83篇 |
1994年 | 89篇 |
1993年 | 74篇 |
1992年 | 38篇 |
1991年 | 27篇 |
1990年 | 25篇 |
1989年 | 25篇 |
1988年 | 20篇 |
1987年 | 14篇 |
1986年 | 15篇 |
1985年 | 8篇 |
1984年 | 10篇 |
1983年 | 11篇 |
1981年 | 7篇 |
1980年 | 10篇 |
1979年 | 6篇 |
1977年 | 7篇 |
1976年 | 15篇 |
1974年 | 7篇 |
1971年 | 7篇 |
1970年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Jinho Choi Sanghun Jung Deok Gun Park Jaegul Choo Niklas Elmqvist 《Computer Graphics Forum》2019,38(3):249-260
The majority of visualizations on the web are still stored as raster images, making them inaccessible to visually impaired users. We propose a deep‐neural‐network‐based approach that automatically recognizes key elements in a visualization, including a visualization type, graphical elements, labels, legends, and most importantly, the original data conveyed in the visualization. We leverage such extracted information to provide visually impaired people with the reading of the extracted information. Based on interviews with visually impaired users, we built a Google Chrome extension designed to work with screen reader software to automatically decode charts on a webpage using our pipeline. We compared the performance of the back‐end algorithm with existing methods and evaluated the utility using qualitative feedback from visually impaired users. 相似文献
5.
6.
A new process for solid phase crystallization (SPC) of amorphous silicon (a-Si) using thin film heater is reported. With this localized Ti silicide thin film heater, we successfully crystallized 500 Å-thick a-Si in a few minutes without any thermal deformation of glass substrate. The size of crystallized silicon grain was abnormally big (30-40 μm). Polycrystalline thin film transistors (TFT) fabricated using this unique thin film heater showed better mobility than those of conventional ones by furnace annealing. 相似文献
7.
8.
The transmission mode of holographic polymer‐dispersed liquid crystals (HPDLCs) was developed an under electric field. It is reported that orientation of LC molecules under an electric field induces orientation of oligomer molecules giving rise to low off‐state diffraction and small grating shrinkage. Copyright © 2005 Society of Chemical Industry 相似文献
9.
Erv J. Kuhlmann Dick Y. Jung Richard P. Guptill Charles A. Dyke Hyung K. Zang 《Fuel》1985,64(11):1552-1557
The presence of hydroaromatic, hydrogen donor components in a coal-derived solvent is one of the more important factors in the successful operation of a non-catalytic coal liquefaction process. Various hydrogen donor species present in a hydrogenated creosote oil have been identified. Their rate of disappearance under conditions that are consistent with a short residence time coal liquefaction process has been used to rank the reactivities of the various hydrogen donors. 1,2,3,10b-Tetrahydrofluoranthene was found to be an exceptional donor while 4,5-dihydropyrene, the hexahydropyrenes and 9,10-dihydrophenanthrene were found to be quite active. Sym.-octahydrophenanthrene and 2a,3,4,5-tetrahydroacenaphthene exhibited moderate activity. Tetralin and the four methyltetralin isomers were found to be unreactive under the coal liquefaction conditions employed. 相似文献
10.
Design and practical implementation of multifrequency RF front ends using direct RF sampling 总被引:1,自引:0,他引:1
Psiaki M.L. Powell S.P. Hee Jung Kintner P.M. 《Microwave Theory and Techniques》2005,53(10):3082-3089
The use of direct RF sampling has been explored as a means of designing multifrequency RF front ends. Such front ends will be useful to multifrequency RF applications such as global navigation satellite system receivers that use global positioning system (GPS) L1, L2, and L5 signals and Galileo signals. The design of a practical multifrequency direct RF sampling front end is dependent on having an analog-to-digital converter whose input bandwidth accommodates the highest carrier frequency and whose maximum sampling frequency is more than twice the cumulative bandwidth about the multiple carrier signals. The principle of direct RF sampling is used to alias all frequency bands of interest onto portions of the Nyquist bandwidth that do not overlap. This paper presents a new algorithm that finds the minimum sampling frequency that avoids overlap. This design approach requires a multifrequency bandpass filter for the frequency bands of interest. A prototype front end has been designed, built, and tested. It receives a GPS coarse/acquisition code at the L1 frequency and GPS antispoofing precision code at both L1 and L2. Dual-frequency signals with received carrier-to-noise ratios in excess of 52 dB-Hz have been acquired and tracked using this system. 相似文献