全文获取类型
收费全文 | 6078篇 |
免费 | 377篇 |
国内免费 | 21篇 |
专业分类
电工技术 | 127篇 |
综合类 | 4篇 |
化学工业 | 1398篇 |
金属工艺 | 240篇 |
机械仪表 | 386篇 |
建筑科学 | 113篇 |
矿业工程 | 2篇 |
能源动力 | 335篇 |
轻工业 | 512篇 |
水利工程 | 24篇 |
石油天然气 | 6篇 |
武器工业 | 2篇 |
无线电 | 963篇 |
一般工业技术 | 1464篇 |
冶金工业 | 313篇 |
原子能技术 | 65篇 |
自动化技术 | 522篇 |
出版年
2024年 | 5篇 |
2023年 | 75篇 |
2022年 | 99篇 |
2021年 | 172篇 |
2020年 | 152篇 |
2019年 | 141篇 |
2018年 | 190篇 |
2017年 | 185篇 |
2016年 | 210篇 |
2015年 | 157篇 |
2014年 | 267篇 |
2013年 | 358篇 |
2012年 | 443篇 |
2011年 | 508篇 |
2010年 | 357篇 |
2009年 | 408篇 |
2008年 | 370篇 |
2007年 | 305篇 |
2006年 | 232篇 |
2005年 | 221篇 |
2004年 | 186篇 |
2003年 | 162篇 |
2002年 | 168篇 |
2001年 | 133篇 |
2000年 | 140篇 |
1999年 | 110篇 |
1998年 | 147篇 |
1997年 | 126篇 |
1996年 | 90篇 |
1995年 | 72篇 |
1994年 | 48篇 |
1993年 | 46篇 |
1992年 | 29篇 |
1991年 | 19篇 |
1990年 | 22篇 |
1989年 | 22篇 |
1988年 | 18篇 |
1987年 | 16篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 8篇 |
1982年 | 9篇 |
1981年 | 5篇 |
1979年 | 3篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有6476条查询结果,搜索用时 15 毫秒
51.
JaeHyunKim JounHoLee JiChulLim ChangHoonLee MooHyoungSong JuYeonYoon HeeDongChoi JeomJaeKim ChangHoOh SangDeogYeo 李路海 《现代显示》2004,31(5):31-33
薄膜晶体管液晶电视(TFT-LCD TV)因为具有薄、轻、紧凑和可随意放置的特点,已经占据了大部分电视机市场。除了这些物理特性以外,最重要的特性是已具有了良好像质的对比度。为了将对比度提高到1:600以上,对偏振片膜、背光源板、滤色片树脂、电极锥角和摩擦条件等都进行了研究。优化的背光板组合,光滑的电极锥角和摩擦方法的控制是提高对比度的主要控制因素。应用新开发的滤色片树脂,对获得高对比度最为有效。 相似文献
52.
53.
J.-M. Yoon M.-H. Cho J.-E. Park Y.-H. Kim T.-R. Hahn Y.-S. Paik 《Journal of food science》2003,68(3):839-843
ABSTRACT Three major yellow pigments were isolated from safflower petals ( Carthamus tinctorius ) and characterized as hydroxysafflor yellow A (1), safflor yellow B (2), and precarthamin (3) by 1 H-NMR, 1 H-1 H COSY, 13 C-NMR, HMQC, and HMBC spectral analysis. Thermal degradation reactions of 3 yellow pigments 1 to 3 at temperatures of 70 to 90 °C were carried out at different pH levels within the range of 3.0 to 10.0 by UV-vis spectral measurements. First-order reaction kinetics was observed for the degradation of safflower yellow pigments (1 to 3) at pH 3.0 and 5.0. Activation energies of thermal degradation of 1-3 at pH 5.0 were calculated as 17.0, 15.4, and 20.1 kcal/mol, respectively. At neutral and alkaline conditions, yellow pigments 1-3 did not follow simple first-order kinetics. 相似文献
54.
55.
We present a structured procedure for order pick system (OPS) analysis and design that has been established on literature review and interviews with and presentations to OPS experts. In particular, we attempt to include the thinking processes that occur between OPS designers and owners. The design procedure and related issues are discussed in the order of input, selection, and evaluation stages. 相似文献
56.
57.
Moon-chul Yoon Do-hun Chin 《The International Journal of Advanced Manufacturing Technology》2006,29(11-12):1125-1133
To analyze the chatter mechanics, the power spectrum of a time series method was analyzed by considering cutting and structural dynamics. In this study, several time series models such as AR (burg, least square, yule walker, geometric lattice, instrument variable), ARX (arx, iv4), ARMAX, ARMA, Box Jenkins, Output Error were modeled and compared with one another. Finally, it was proved that arx, armax and iv4 are more desirable and reliable algorithms than the others for the calculation of the chatter mode in the endmilling operation. The cutting forces Fx and Fz have more powerful effects on the chatter than Fy in the sense that there is no shifting or pseudo mode in the power spectrum. 相似文献
58.
Surface and normal ensembles for surface reconstruction 总被引:1,自引:0,他引:1
The majority of the existing techniques for surface reconstruction and the closely related problem of normal reconstruction are deterministic. Their main advantages are the speed and, given a reasonably good initial input, the high quality of the reconstructed surfaces. Nevertheless, their deterministic nature may hinder them from effectively handling incomplete data with noise and outliers. An ensemble is a statistical technique which can improve the performance of deterministic algorithms by putting them into a statistics based probabilistic setting. In this paper, we study the suitability of ensembles in normal and surface reconstruction. We experimented with a widely used normal reconstruction technique [Hoppe H, DeRose T, Duchamp T, McDonald J, Stuetzle W. Surface reconstruction from unorganized points. Computer Graphics 1992;71-8] and Multi-level Partitions of Unity implicits for surface reconstruction [Ohtake Y, Belyaev A, Alexa M, Turk G, Seidel H-P. Multi-level partition of unity implicits. ACM Transactions on Graphics 2003;22(3):463-70], showing that normal and surface ensembles can successfully be combined to handle noisy point sets. 相似文献
59.
Kyeong-Sik Shin Kyeong-Kap Paek Jung-Ho Park Tae-Song Kim Byeong-Kwon Ju Ji Yoon Kang 《Electron Device Letters, IEEE》2007,28(7):581-583
In this letter, we examined whether the parasitic bipolar junction transistors (BJTs) in the MOSFET fabricated by the standard CMOS process can play a role as a fluorescence detector. To suppress the action of two vertical parasitic BJTs, the gate and n-well were tied in the parasitic BJTs, and the body node was connected to the drain. The proposed device was compared with the inherent and the parasitic diodes in the MOSFET. It had 100 times higher photocurrents than the diodes in the MOSFET. In addition, it was applied for the detection of the fluorescent signal, and could detect near 10 nM of Alexa 546. Therefore, CMOS-process-compatible parasitic BJTs can be used as a photodetector in an integrated fluorescence detector. 相似文献
60.
Chang-Bun Yoon Seung-Ho Lee Sung-Mi Lee Young-Hag Koh Hyoun-Ee Kim Kyung-Woo Lee 《Journal of the American Ceramic Society》2006,89(8):2509-2513
A multilayer piezoelectric ceramic/polymer composite with 2–2 connectivity was fabricated by thermoplastic green machining after co-extrusion. The multilayer ceramic body was composed of piezoelectrically active lead zirconate titanate (PZN)–lead zinc niobate (PZN)-lead zirconate titanate (PZT) layers and electrically conducting PZN–PZT/Ag layers. After co-extruding the thermoplastic body, which consisted of five piezoelectric layers interspersed with four conducting layers, it was computer numeric-controlled machined to create periodic channels within it. Following binder burnout and sintering, an 18 vol% array of 190 μm thin PZT slabs with a channel size of 880 μm was fabricated. The channels were filled with epoxy in order to fabricate a PZN–PZT/epoxy composite with 2–2 connectivity. The piezoelectric coefficient (effective d 33 ) and hydrostatic figure of merit ( d h × g h ) of the PZN–PZT/epoxy composite were 1200 pC/N and 20 130 × 10−15 m2 /N, respectively. These excellent piezoelectric characteristics as well as the relatively simple fabrication procedure will contribute in widening the application range of the piezoelectric transducers. 相似文献