全文获取类型
收费全文 | 65247篇 |
免费 | 5819篇 |
国内免费 | 2709篇 |
专业分类
电工技术 | 3670篇 |
技术理论 | 4篇 |
综合类 | 3676篇 |
化学工业 | 11016篇 |
金属工艺 | 3658篇 |
机械仪表 | 4426篇 |
建筑科学 | 4420篇 |
矿业工程 | 1755篇 |
能源动力 | 2117篇 |
轻工业 | 4719篇 |
水利工程 | 1201篇 |
石油天然气 | 2854篇 |
武器工业 | 553篇 |
无线电 | 8146篇 |
一般工业技术 | 8685篇 |
冶金工业 | 3448篇 |
原子能技术 | 982篇 |
自动化技术 | 8445篇 |
出版年
2024年 | 275篇 |
2023年 | 1101篇 |
2022年 | 1920篇 |
2021年 | 2710篇 |
2020年 | 2055篇 |
2019年 | 1799篇 |
2018年 | 2063篇 |
2017年 | 2205篇 |
2016年 | 2137篇 |
2015年 | 2610篇 |
2014年 | 3326篇 |
2013年 | 4040篇 |
2012年 | 4569篇 |
2011年 | 4895篇 |
2010年 | 4169篇 |
2009年 | 4028篇 |
2008年 | 3824篇 |
2007年 | 3480篇 |
2006年 | 3274篇 |
2005年 | 2773篇 |
2004年 | 2142篇 |
2003年 | 1938篇 |
2002年 | 2024篇 |
2001年 | 1768篇 |
2000年 | 1436篇 |
1999年 | 1397篇 |
1998年 | 1176篇 |
1997年 | 865篇 |
1996年 | 777篇 |
1995年 | 643篇 |
1994年 | 497篇 |
1993年 | 404篇 |
1992年 | 311篇 |
1991年 | 246篇 |
1990年 | 186篇 |
1989年 | 135篇 |
1988年 | 139篇 |
1987年 | 85篇 |
1986年 | 78篇 |
1985年 | 42篇 |
1984年 | 40篇 |
1983年 | 33篇 |
1982年 | 23篇 |
1981年 | 21篇 |
1980年 | 16篇 |
1979年 | 18篇 |
1977年 | 19篇 |
1976年 | 21篇 |
1975年 | 8篇 |
1970年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
1.
Shi-Jin Ding Hang Hu Lim H.F. Kim S.J. Yu X.F. Chunxiang Zhu Li M.F. Byung Jin Cho Chan D.S.H. Rustagi S.C. Yu M.B. Chin A. Dim-Lee Kwong 《Electron Device Letters, IEEE》2003,24(12):730-732
For the first time, we successfully fabricated and demonstrated high performance metal-insulator-metal (MIM) capacitors with HfO/sub 2/-Al/sub 2/O/sub 3/ laminate dielectric using atomic layer deposition (ALD) technique. Our data indicates that the laminate MIM capacitor can provide high capacitance density of 12.8 fF//spl mu/m/sup 2/ from 10 kHz up to 20 GHz, very low leakage current of 3.2 /spl times/ 10/sup -8/ A/cm/sup 2/ at 3.3 V, small linear voltage coefficient of capacitance of 240 ppm/V together with quadratic one of 1830 ppm/V/sup 2/, temperature coefficient of capacitance of 182 ppm//spl deg/C, and high breakdown field of /spl sim/6 MV/cm as well as promising reliability. As a result, the HfO/sub 2/-Al/sub 2/O/sub 3/ laminate is a very promising candidate for next generation MIM capacitor for radio frequency and mixed signal integrated circuit applications. 相似文献
2.
Jeong-Soo Lee Yang-Kyu Choi Daewon Ha Balasubramanian S. Tsu-Jae King Bokor J. 《Electron Device Letters, IEEE》2003,24(3):186-188
The hydrogen annealing process has been used to improve surface roughness of the Si-fin in CMOS FinFETs for the first time. Hydrogen annealing was performed after Si-fin etch and before gate oxidation. As a result, increased saturation current with a lowered threshold voltage and a decreased low-frequency noise level over the entire range of drain current have been attained. The low-frequency noise characteristics indicate that the oxide trap density is reduced by a factor of 3 due to annealing. These results suggest that hydrogen annealing is very effective for improving device performance and for attaining a high-quality surface of the etched Si-fin. 相似文献
3.
关于我国钢铁工业发展战略的思考 总被引:2,自引:0,他引:2
21世纪初是世界经济发展的重大战略机遇期,如何抓住机遇加快发展,是中国钢铁行业应认真思考的问题。十一五我国钢铁工业的发展,靠什么来拉动,还能靠大规模的投资吗?目前我们还不能生产的双高产品怎么办,靠花钱能买来技术吗?靠市场能换来核心产品吗?值得深思。当今,我们思考的不仅应考虑个别企业的生存问题,而更应考虑的是钢铁行业整体的长远发展问题,即 相似文献
4.
Maenghyo Cho Hee Yuel Roh 《International journal for numerical methods in engineering》2003,56(1):81-115
In the present study first‐order shear deformable shell finite elements based on general curvilinear co‐ordinates are proposed. For the development of the present shell elements, a partial mixed variational functional with independently assumed strains is provided in order to avoid the severe locking troubles known as transverse shear and membrane lockings. Bubble functions are included in the shape function of displacement to improve the performance of the developed element. The proposed assumed strain four‐ and nine‐node elements based on the general tensor shell theory provide an efficient linkage framework for shell surface modelling and finite element analysis. In the several benchmark problems, the present shell elements with exact geometric representations demonstrate their performance compared to previously reported results. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
5.
Development of a recurrent Sigma-Pi neural network rainfall forecasting system in Hong Kong 总被引:1,自引:1,他引:0
At the moment, weather forecasting is still an art — the experience and intuition of forecasters play a significant role in determining the quality of forecasting. This paper describes the development of a new approach to rainfall forecasting using neural networks. It deals with the extraction of information from radar images and an evaluation of past rain gauge records to provide shortterm rainfall forecasting. All of the meteorological data were provided by the Royal Observatory of Hong Kong (ROHK). Preprocessing procedures were essential for this neural network rainfall forecasting. The forecast of the rainfall was performed every half an hour so that a storm warning signal can be delivered to the public in advance. The network architecture is based on a recurrent Sigma-Pi network. The results are very promising, and this neural-based rainfall forecasting system is capable of providing a rain storm warning signal to the Hong Kong public one hour ahead. 相似文献
6.
Douay M. Xie W.X. Taunay T. Bernage P. Niay P. Cordier P. Poumellec B. Dong L. Bayon J.F. Poignant H. Delevaque E. 《Lightwave Technology, Journal of》1997,15(8):1329-1342
A comprehensive survey of photosensitivity in silica glasses and optical fiber is reviewed. Recent work on understanding the mechanisms contributing to germanium or aluminum doped fiber photosensitivity is discussed within the framework of photoelastic densification models 相似文献
7.
本文提出新型布线算法,集李氏迷宫法与线搜索法的长处为一体,以饱和带法进行动态排序,以线搜索法确定借孔位置,然后用李氏法进行单层布线,获得最佳路径,从而达到线型好,布通率高的效果。 相似文献
9.
10.
Bongkee Cho 《Polymer Engineering and Science》1985,25(18):1139-1144