全文获取类型
收费全文 | 631篇 |
免费 | 14篇 |
专业分类
电工技术 | 42篇 |
化学工业 | 219篇 |
金属工艺 | 14篇 |
机械仪表 | 22篇 |
建筑科学 | 8篇 |
能源动力 | 14篇 |
轻工业 | 34篇 |
无线电 | 31篇 |
一般工业技术 | 108篇 |
冶金工业 | 21篇 |
原子能技术 | 22篇 |
自动化技术 | 110篇 |
出版年
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 6篇 |
2020年 | 11篇 |
2019年 | 5篇 |
2018年 | 12篇 |
2017年 | 5篇 |
2016年 | 11篇 |
2015年 | 10篇 |
2014年 | 19篇 |
2013年 | 28篇 |
2012年 | 25篇 |
2011年 | 38篇 |
2010年 | 22篇 |
2009年 | 40篇 |
2008年 | 56篇 |
2007年 | 36篇 |
2006年 | 21篇 |
2005年 | 25篇 |
2004年 | 23篇 |
2003年 | 14篇 |
2002年 | 23篇 |
2001年 | 10篇 |
2000年 | 7篇 |
1999年 | 14篇 |
1998年 | 19篇 |
1997年 | 13篇 |
1996年 | 19篇 |
1995年 | 9篇 |
1994年 | 9篇 |
1993年 | 8篇 |
1992年 | 8篇 |
1991年 | 4篇 |
1990年 | 10篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 5篇 |
1983年 | 9篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 7篇 |
1976年 | 10篇 |
1975年 | 2篇 |
1972年 | 2篇 |
1968年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有645条查询结果,搜索用时 15 毫秒
51.
Tatsuhiko Matsumoto Satoru Kubota Yuta Kubota Kenta Imabayashi Kazuyuki Kishimoto Seiichi Goshi Shigeki Imai Youichi Igarashi Shuichi Haga Takehiro Nakatsue 《Journal of the Society for Information Display》2011,19(11):813-820
Abstract— To understand actual viewing conditions at home is important for TV design. And the preferred luminance level of LCD TVs under actual viewing conditions is also important in order to obtain both good picture quality and low power consumption. The actual viewing conditions of households and the preferred luminance levels was investigated. In a field test of 83 households, the display luminance, screen illuminance, and viewing locations were measured on site. In laboratory experiments, young and elderly subjects adjusted the luminance of an LCD‐TV screen to their preferred levels under different screen illuminance levels, angular screen sizes, and average luminance levels (ALL) of the images. As a result, two equations, which represent the preferred luminance level of LCD‐TV screens corresponding to different viewing conditions for young and elderly subjects were obtained. When the ALL of the images was 25% and the screen illuminance and angular screen size were set at 100 lx and 20°, respectively, the preferred luminance was 1 60 cd/m2 for the young subjects and 248 cd/m2 for the elderly subjects. By using the setting of the preferred luminance of an LCD TV under actual viewing conditions, it is possible to conserve energy consumption. 相似文献
52.
Satofumi Souma Matsuto Ogawa Takahiro Yamamoto Kazuyuki Watanabe 《Journal of Computational Electronics》2011,10(1-2):35-43
We show computationally that the current-voltage characteristics of the zigzag-edged graphene nanoribbon (ZGNR) with the even width exhibit remarkable current saturation behavior in spite of the absence of the bandgap. Mechanism of such current-saturation behavior can be understood to be originated from the symmetries of the wavefunctions corresponding to the edge states in ZGNR. We further demonstrate that the current-voltage characteristics of ZGNR can be drastically changed even by the presence of a single lattice vacancy, with the strong dependence on the position of the vacancy. The origin of such properties is intuitively understood by analyzing the transmission probabilities through such systems. 相似文献
53.
Toshiyuki Miyamoto Tomohiro Kitayama Sadatoshi Kumagai Kazuyuki Mori Syoichi Kitamura Seiichi Shindo 《Electrical Engineering in Japan》2008,162(4):54-63
Abatement of CO2 emission is one of the most important issues in the 21st century regarding preservation of the earth environment. This paper addresses a utility operations planning problem for distributed energy management systems (DEMSs), where we are to obtain optimal plans that minimize both costs and CO2 emissions. A DEMS consists of multiple entities that seek their own economic profits. In this paper, we give a mathematical formulation of the utility operations planning problem for each entity, and propose an energy trading market, which utlizes a multi‐attribute auction protocol in order to deal with both a price and a CO2 emission rate. Experimental results show that collaboration among entities through the market provides a more profitable plan for each entity and abatement of CO2 emission is also achieved. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(4): 54–63, 2008; Published online in Wiley InterScience ( www.interscience.wiley. com ). DOI 10.1002/eej.20418 相似文献
54.
Here, the development of ordered mesoporous silica prepared by the reaction of layered silicates with organoammonium surfactants is reviewed. The specific features of mesoporous silica are discussed with relation to the probable formation mechanisms. The recent understanding of the unusual structural changes from the 2D structure to periodic 3D mesostructures is presented. The formation of mesophase silicates from layered silicates with single silicate sheets depends on combined factors including the reactivity of layered silicates, the presence of layered intermediates, the variation of the silicate sheets, and the assemblies of surfactant molecules in the interlayer spaces. FSM‐16‐type (p6mm) mesoporous silica is formed via layered intermediates composed of fragmented silicate sheets and alkyltrimethylammonium (CnTMA) cations. KSW‐2‐type (c2mm) mesoporous silica can be prepared through the bending of the individual silicate sheets with intralayer and interlayer condensation. Although the structure of the silicate sheets changes during the reactions with CnTMA cations in a complex manner, the structural units caused by kanemite in the frameworks are retained. Recent development of the structural design in the silicate framework is very important for obtaining KSW‐2‐based mesoporous silica with molecularly ordered frameworks. The structural units originating from layered silicates are chemically designed and structurally stabilized by direct silylation of as‐synthesized KSW‐2. Some proposed applications using these mesoporous silica are also summarized with some remarks on the uniqueness of the use of layered silicates by comparison with MCM‐type mesoporous silica. 相似文献
55.
56.
iopeNet及其目的 总被引:1,自引:0,他引:1
我们已经提出的新的开放式区域控制网络“iopeNet”是一个全新的概念,与现有的设备控制网络没有冲突。本资料就此加以阐释。 相似文献
57.
Yusuke Takeuchi Fangming Jin Kazuyuki Tohji Heiji Enomoto 《Journal of Materials Science》2008,43(7):2472-2475
Acidic hydrothermal degradation of glucose was examined in the presence of HCl, H2SO4, and H3PO4 with pH varying from 1.5 to 2.5 and reaction time varying from 1 to 10 min at 523 K, to investigate the effect of different
acid catalysts and acid concentration on the production of 5-hydroxymethyl-2-furaldehyde (HMF) and levulinic acid from glucose.
At lower acidities of pH 2.5, a considerably higher amount of HMF was produced. The increase in acid concentration accelerated
the conversion of HMF to levulinic acid. The order for the production of HMF using the three acids is in the sequence of H3PO4 > H2SO4 > HCl. On the contrary, the order for production of levulinic acid follows HCl > H2SO4 > H3PO4. In the experimental conditions used in this study, the highest yield of levulinic acid is about 55%, which was obtained
at pH 1.5 for 5 min in the case of HCl as an acid catalyst, and the total highest yields of HMF and levulinic acid are about
50%, which occurred at pH 2.0 for 5 min in the case of H3PO4 as an acid catalyst. 相似文献
58.
59.
60.
Chen D Gao L Yasumori A Kuroda K Sugahara Y 《Small (Weinheim an der Bergstrasse, Germany)》2008,4(10):1813-1822
Two-dimensional monoclinic WO(3) nanoplates with high specific surface areas are synthesized through a novel conversion process using tungstate-based inorganic-organic hybrid micro/nanobelts as precursors. The process developed involves a topochemical transformation of tungstate-based inorganic-organic hybrid belts into WO(3) nanoplates via an intermediate product of H(2)WO(4) nanoplates, utilizing the similarity of the W-O octahedral layers in both H(2)WO(4) and WO(3). The as-obtained WO(3) nanoplates show a single-crystalline nanostructure with the smallest side along the [001] direction. The WO(3) nanoplates are 200-500 nm x 200-500 nm x 10-30 nm in size, and their specific surface areas are up to 180 m(2) g(-1). Photocatalytic measurements of visible-light-driven oxidation of water for O(2) generation in the presence of Ag(+) ions indicate that the activity of the as-obtained WO(3) nanoplates is one order of magnitude higher than that of commercially available WO(3) powders. 相似文献