全文获取类型
收费全文 | 1272篇 |
免费 | 17篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 40篇 |
化学工业 | 272篇 |
金属工艺 | 26篇 |
机械仪表 | 21篇 |
建筑科学 | 10篇 |
能源动力 | 37篇 |
轻工业 | 61篇 |
水利工程 | 1篇 |
无线电 | 229篇 |
一般工业技术 | 180篇 |
冶金工业 | 304篇 |
原子能技术 | 35篇 |
自动化技术 | 75篇 |
出版年
2022年 | 12篇 |
2021年 | 13篇 |
2020年 | 6篇 |
2019年 | 12篇 |
2018年 | 14篇 |
2017年 | 9篇 |
2016年 | 11篇 |
2015年 | 19篇 |
2014年 | 17篇 |
2013年 | 43篇 |
2012年 | 23篇 |
2011年 | 47篇 |
2010年 | 36篇 |
2009年 | 47篇 |
2008年 | 39篇 |
2007年 | 33篇 |
2006年 | 38篇 |
2005年 | 33篇 |
2004年 | 41篇 |
2003年 | 54篇 |
2002年 | 30篇 |
2001年 | 32篇 |
2000年 | 27篇 |
1999年 | 39篇 |
1998年 | 128篇 |
1997年 | 66篇 |
1996年 | 59篇 |
1995年 | 53篇 |
1994年 | 37篇 |
1993年 | 37篇 |
1992年 | 29篇 |
1991年 | 23篇 |
1990年 | 17篇 |
1989年 | 17篇 |
1988年 | 14篇 |
1987年 | 12篇 |
1986年 | 9篇 |
1985年 | 14篇 |
1984年 | 13篇 |
1983年 | 11篇 |
1982年 | 10篇 |
1981年 | 16篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 11篇 |
1976年 | 9篇 |
1968年 | 2篇 |
1967年 | 3篇 |
1966年 | 2篇 |
排序方式: 共有1291条查询结果,搜索用时 15 毫秒
991.
992.
Toshinobu Sasa Hiroyuki Oigawa Kazufumi Tsujimoto Kenji Nishihara Kenji Kikuchi Yuji Kurata Shigeru Saito Masatoshi Futakawa Makoto Umeno Nobuo Ouchi Yasuo Arai Kazuo Minato Hideki Takano 《Nuclear Engineering and Design》2004,230(1-3):209-222
Japan Atomic Energy Research Institute carries out research and development on accelerator-driven system (ADS) to transmute minor actinides and long-lived fission products in high-level radioactive waste. The system is composed of high intensity proton accelerator, lead-bismuth spallation target and lead-bismuth cooled subcritical core with nitride fuel. About 2500 kg of minor actinide is loaded into the subcritical core. Annual transmutation amount using this system is 250 kg with 800 MW of thermal output. This transmutation amount corresponds to the amount of minor actinides produced from 10 units of 1GWe power reactors annually. A superconducting linear accelerator with the beam power of 20–30 MW is connected to drive the subcritical core. To maximize the transmutation efficiency, the nitride fuel without uranium, such as (Np, Am, Pu)N, is selected. The nitride fuel irradiated in the ADS is reprocessed by pyrochemical process followed by the re-fabrication of nitride fuel. Many research and development activities are under way and planned in the fields of subcritical core design, spallation target technology, lead-bismuth handling technology, accelerator development, and minor actinide fuel development. Especially, to study and evaluate the feasibility of the ADS from physics and engineering aspects, the transmutation experimental facility (TEF) is proposed under a framework of the High-Intensity Proton Accelerator Project. 相似文献
993.
A Kinematic Calibration Method for Industrial Robots Using Autonomous Visual Measurement 总被引:1,自引:0,他引:1
Several new methods have been developed to achieve practical accuracy for offline programming of robots and its applicability to the real world. In this paper, a new kinematic calibration method is proposed to automatically improve absolute positioning accuracy of robots. Key points of the method include autonomous measurement and the automatic generation of measuring poses. A new visual feedback motion control method of the robot is proposed to achieve accurate measurement. An algorithm is also proposed to improve the condition of measuring poses automatically. The effectiveness of the proposed methods and algorithm was investigated through experiments with actual robots. 相似文献
994.
We studied integral photography (IP), which creates three-dimensional autostereoscopic images. In particular we studied the possibility of a new method that uses a television camera to shoot directly numerous real images produced by a lens array. Unlike the conventional IP method in which the film is placed immediately behind a lens array, this method employs a television camera, which enables us to shoot moving pictures. Of a number of factors affecting the process of image pickup, we examined some optical factors and compared them with those obtained by the conventional IP method. The results show that with this new direct pickup method that uses a television camera, we can obtain an IP image like those obtained by using the conventional IP method. Further, we conducted an experiment with an high-definition TV camera, confirming the production of an autostereoscopic image by using a display device that combines a liquid-crystal panel and pinholes. 相似文献
995.
Narihiro Morosawa Yoshihiro Ohshima Mitsuo Morooka Toshiaki Arai Tatsuya Sasaoka 《Journal of the Society for Information Display》2012,20(1):47-52
Abstract— A novel highly reliable self‐aligned top‐gate oxide‐semiconductor thin‐film transistor (TFT) formed by using the aluminum (Al) reaction method has been developed. This TFT structure has advantages such as small‐sized TFTs, lower mask count, and small parasitic capacitance. The TFT with a 4‐μm channel length exhibited a field‐effect mobility of 21.6 cm2/V‐sec, a threshold voltage of ?1.2 V, and a subthreshold swing of 0.12 V/decade. Highly reliable TFTs were obtained after 300°C annealing without increasing the sheet resistivity of the source/drain region. A 9.9‐in.‐diagonal qHD AMOLED display was demonstrated with self‐aligned top‐gate oxide‐semiconductor TFTs for a low‐cost and ultra‐high‐definition OLED display. Excellent brightness uniformity could be achieved due to small parasitic capacitance. 相似文献
996.
Reginaldo Teixeira Coelho Ricardo Arai Hugo Martinelli Watanuki Emanuel Borges 《Machining Science and Technology》2013,17(2):235-250
Tapping is one of the most intensively used operations for internal threads with diameters below about 15 mm. When a tap fails, the workpiece has a significant added value. The present work investigates some aspects of wear and performance when solid carbide coated taps M10 × 1.5 cut hardened AISI H13 and AISI D2. The results indicated that it was possible to make threads on hardened AISI D2, although the number of holes was essentially low and tool breakage was often. Threads on hardened AISI H13 was possible with reasonably low tool wear. Cutting surface presented some indication of small flaws due to the adhered material on the taps. 相似文献
997.
Nektarios Chrysoulakis Michael Abrams Haralambos Feidas Korei Arai 《International journal of remote sensing》2013,34(24):6347-6385
The purpose of atmospheric correction is to produce more accurate surface reflectance and to potentially improve the extraction of surface parameters from satellite images. To achieve this goal the influences of the atmosphere, solar illumination, sensor viewing geometry and terrain information have to be taken into account. Although a lot of information from satellite imagery can be extracted without atmospheric correction, the physically based approach offers advantages, especially when dealing with multitemporal data and/or when a comparison of data provided by different sensors is required. The use of atmospheric correction models is limited by the need to supply data related to the condition of the atmosphere at the time of imaging. Such data are not always available and the cost of their collection is considerable, hence atmospheric correction is performed with the use of standard atmospheric profiles. The use of these profiles results in a loss of accuracy. Therefore, site-dependent databases of atmospheric parameters are needed to calibrate and to adjust atmospheric correction methods for local level applications. In this article, the methodology and results of the project Adjustment of Atmospheric Correction Methods for Local Studies: Application in ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) (ATMOSAT) for the area of Crete are presented. ATMOSAT aimed at comparing several atmospheric correction methods for the area of Crete, as well as investigating the effects of atmospheric correction on land cover classification and change detection. Databases of spatio-temporal distributions of all required input parameters (atmospheric humidity, aerosols, spectral signatures, land cover and elevation) were developed and four atmospheric correction methods were applied and compared. The baseline for this comparison is the spatial distribution of surface reflectance, emitted radiance and brightness temperature as derived by ASTER Higher Level Products (HLPs). The comparison showed that a simple image based method, which was adjusted for the study area, provided satisfactory results for visible, near infrared and short-wave infrared spectral areas; therefore it can be used for local level applications. Finally, the effects of atmospheric correction on land cover classification and change detection were assessed using a time series of ASTER multispectral images acquired in 2000, 2002, 2004 and 2006. Results are in agreement with past studies, indicating that for this type of application, where a common radiometric scale is assumed among the multitemporal images, atmospheric correction should be taken into consideration in pre-processing. 相似文献
998.
Michihiro Okuda Shinya Matsumoto Makoto Maeda Kazuhiro Arai Kiyoko Tsuji Takahisa Ando Takaaki Abe Masutaka Inoue Ryuhei Amano Takashi Ikeda Hideyuki Kanayama 《Journal of the Society for Information Display》2011,19(2):221-229
Abstract— A novel laser‐light‐source projector having the three outstanding features of high brightness, ultra‐short throw distance, and high color reproduction has been developed.These features have recently come to be required in the high‐end projector market. The technologies for the laser‐light‐source projectors fully utilize the advantages of lasers, such as high luminance, small étendue, and high color purity. By integrating a triple‐rod illumination system with a multi‐laser light source and an ultra‐wide‐angle projection system, the developed high‐efficiency optical system has achieved a brightness of 7000 lm and a throw ratio of 0.28 with an image size of 100–150 in. Another new technology, laser color processing (LCP), has offered vivid color reproduction which has a color gamut that is up to 180% wider than the BT.709 standard without appearing unnaturally colored. Furthermore, a speckle suppression effect produced by the multi‐laser light source has been demonstrated. In this paper, an overview of these newly developed technologies that are used in the novel laser‐light‐source projector is presented, and solutions to the issues of speckle noise and safety are presented. 相似文献
999.
Yuichi Yoshida Yoko Arai Shigeru Kado Kimio Kunimori Keiichi Tomishige 《Catalysis Today》2006,115(1-4):95-101
The catalytic properties of CeO2 catalysts in direct synthesis of dimethyl carbonate (DMC) from CH3OH and CO2 were investigated. The formation rate of DMC over the catalysts calcined at 873 K and above was almost proportional to the surface area of catalysts. However, CeO2 calcined at 673 K showed lower activity than expected from the surface area. From the results of catalyst characterization, CeO2 calcined at 673 K contained considerable amount of amorphous phase. In contrast, the ratio of amorphous phase decreased on the catalysts calcined at 873 K and above. This suggests that stable crystallite surface is active for the reaction.
In the CH3OH + C2H5OH + CO2 reaction at low temperature, ethyl methyl carbonate (EMC) was formed, and selectivity of EMC formation was comparable to that of DMC. The formation route is discussed by the comparison with transesterification reaction. 相似文献
1000.
Homogeneity and Properties of Lead Zirconate Titanate Prepared by a Combination of Thermal Spray Decomposition Method with Solid-Phase Reaction 总被引:2,自引:0,他引:2
Kazuyuki Kakegawa Kenji Arai Yoshinori Sasaki Toshiaki Tomizawa 《Journal of the American Ceramic Society》1988,71(1):49-C-
A solution containing titanium and zirconium ions was spray decomposed. The product thus obtained was mixed with PbO powder and fired at high temperatures to obtain Pb(Zr,Ti)O3 (PZT). A phase of PZT began to form at a very low temperature (450°C). This formation reaction was complete at about 650°C. Reactivity of the spray-decomposed product with lead titanate powder was high. For PZT prepared by this process with a firing condition of 1100°C for 1 h, the compositional fluctuation was estimated from the width of the X-ray diffraction peaks. Fluctuations were about 3 at.%. This value agreed with that estimated from the range of the tetragonal-rhombohedral coexistence region near the morphotropic phase boundary. The peak of the dielectric constant near the Curie temperature was sharp and very high (ε∼12000). 相似文献