全文获取类型
收费全文 | 1100篇 |
免费 | 34篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 72篇 |
化学工业 | 272篇 |
金属工艺 | 38篇 |
机械仪表 | 34篇 |
建筑科学 | 23篇 |
能源动力 | 76篇 |
轻工业 | 93篇 |
无线电 | 94篇 |
一般工业技术 | 170篇 |
冶金工业 | 95篇 |
原子能技术 | 55篇 |
自动化技术 | 114篇 |
出版年
2024年 | 3篇 |
2023年 | 12篇 |
2022年 | 20篇 |
2021年 | 35篇 |
2020年 | 19篇 |
2019年 | 15篇 |
2018年 | 24篇 |
2017年 | 23篇 |
2016年 | 25篇 |
2015年 | 23篇 |
2014年 | 32篇 |
2013年 | 81篇 |
2012年 | 58篇 |
2011年 | 96篇 |
2010年 | 68篇 |
2009年 | 57篇 |
2008年 | 52篇 |
2007年 | 59篇 |
2006年 | 43篇 |
2005年 | 40篇 |
2004年 | 24篇 |
2003年 | 27篇 |
2002年 | 27篇 |
2001年 | 16篇 |
2000年 | 12篇 |
1999年 | 22篇 |
1998年 | 42篇 |
1997年 | 34篇 |
1996年 | 13篇 |
1995年 | 16篇 |
1994年 | 8篇 |
1993年 | 14篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 9篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 2篇 |
1974年 | 3篇 |
排序方式: 共有1136条查询结果,搜索用时 187 毫秒
991.
Tatsuya Kikuchi Yasuhito Hara Tetsu Yonezawa Hideaki Takahashi 《Corrosion Science》2010,52(8):2525-2534
Nine kinds of Al alloys were anodized to form porous anodic oxide films, and then anodized specimens were immersed in 2-(2-(2-methoxyethoxy)ethoxy)ethanol (MEEE) and 2-(2-(2-butoxyethoxy)ethoxy)ethanol (BEEE) at 415 K. Al-1.0%Sn-1.0%Bi alloy was corroded severely in both BEEE and MEEE, whereas other eight alloys showed no corrosion. The corrosion proceeded under the anodic oxide films through cracks formed in the film. Cathodic polarization in Cu electroplating solution after corrosion suggested that the crack formation during immersion in hot MEEE is due to thermal expansion of the substrate and Sn and Bi containing particles included in the anodic oxide film. 相似文献
992.
Kazuya Shimoda Sosuke Kondo Tatsuya Hinoki Akira Kohyama 《Journal of the European Ceramic Society》2010,30(12):2643-2652
We explored the thermal relaxation creep characteristics of nanostructured SiC ceramics by bend stress relaxation (BSR) method. The effects of the differences in microstructure and secondary phases by liquid phase sintering at 1800 or 1900 °C were especially discussed, based on microstructural evolutions during the creep. The creep was characterized by the BSR ratio (m) of ~0.80 up to 1200 °C, and the proportion of amorphous phase as a secondary phase was related to the creep resistance at 1300 °C. The microstructural evolutions during the creep consisted firstly in the re-distribution of amorphous phase, probably as a consequence of its viscous flow, and secondly in an extensive nucleation and growth of cavities. Furthermore, the former enhanced inter-diffusion of Al–Y among intergranular areas above the ternary eutectic temperature, which caused the significantly reduced creep resistance, and the latter reflected the crystalline YAG decomposition as another secondary phase near 1500 °C. 相似文献
993.
994.
Taisuke Tokunaga Takeshi Yatabe Takahiro Matsumoto Tatsuya Ando Ki-Seok Yoon 《Science and Technology of Advanced Materials》2013,14(1):870-876
AbstractWe report the mechanistic investigation of catalytic H2 evolution from formic acid in water using a formate-bridged dinuclear Ru complex as a formate hydrogen lyase model. The mechanistic study is based on isotope-labeling experiments involving hydrogen isotope exchange reaction. 相似文献
995.
Abstract Solvent extraction of cobalt(Il) and nickel(II) in aqueous 1 mol dm?3 NaCl solutions with benzoyltrifluoro-acetone(Hbfa) in carbon tetrachloride has been measured in the absence and presence of tetrabutylammonium(tba+). In the absence of tba+, M(bfa)2 species is extracted and the extraction of cobalt(II) is better in the higher Hbfa concentration range but in the presence, M(bfa)3 ?tba+ type ion-pair is extracted and the extraction of nickel-(II) is always better. This is explained in terms that although the bis-nickel(II) complex is more stable, it is much more strongly hydrated than the bis-cobalt(II) complex and consequently its extraction is hindered but in the tris-complexes such a large difference of the hydration may not occur and the more stable nickel(II) complex is extracted better. 相似文献
996.
Kazuyuki Sakaue Hitoshi HayanoShigeru Kashiwagi Ryunosuke KurodaAkihiko Masuda Tatsuya SuzukiToshikazu Takatomi Nobuhiro TerunumaJunji Urakawa Masakazu Washio 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(24):2928-2931
A compact electron accelerator based on photo-cathode RF electron gun is under development for applied research at the Waseda University. Higher charge and higher energy are key issues for applications such as pulse radiolysis experiment and laser-Compton X-ray generation. The new RF-gun cavity with cesium telluride (Cs-Te) photo-cathode which has higher quantum efficiency (Q.E.) compared with metal cathodes has been installed. The evaluation of Q.E. of the photo-cathode has been performed and the value obtained is more than 5% at the preparation stage. For understanding the Cs-Te cathode properties and the higher Q.E. operation, fundamental studies by single bunch beam operation have been performed resulting in more than 6 nC bunch charge with a high Q.E. of 2.9%. Additionally, the new RF-gun cavity was improved for obtaining a higher Q value. Higher beam energy, i.e. shunt impedance compared with old type cavity, was observed. The shunt impedance increased by about 20%. These successful results will considerably contribute to the applied research. 相似文献
997.
Zhihong Zhong Hun-chea Jung Tatsuya Hinoki Akira Kohyama 《Journal of Materials Processing Technology》2010,210(13):1805-1810
A diffusion bonding process, for joining of tungsten to ferritic steel using nickel as an interlayer, was developed for nuclear component application. The effect of joining temperature on the microstructure and tensile strength of the joint was investigated in this work. Metallographic analysis revealed that a good bonding was obtained at both the tungsten/nickel and nickel/steel interfaces, and the diffusion products were identified in the diffusion zone. Nano-indentation test across the joining interfaces demonstrated the effect of solid solution hardening in the diffusion zone. Tensile test showed that the maximum average tensile strength of ∼200 MPa was obtained for the joint diffusion bonded at 900 °C. The results were discussed in terms of the joining temperature and of the residual stress generated during joining process. 相似文献
998.
Norihisa Kusumoto Tatsuya Ashitani Yuichi Hayasaka Tetsuya Murayama Koichi Ogiyama Koetsu Takahashi 《Journal of chemical ecology》2009,35(6):635-642
Eight known abietane-type diterpenes were isolated from the weak acidic fraction of the n-hexane extract from cones of Taxodium distichum, one of the extant, living fossil conifers. They were identified as 6,7-dehydroroyleanone (1), taxodal (2), taxodione (3), salvinolone (4), 14-deoxycoleon U (5), 5,6-dehydrosugiol (6), sandaracopimaric acid (7), and xanthoperol (8). The structures of these compounds were determined by comparison of NMR spectral data with published data. The antitermitic
(termicidal and antifeedant) activities of the compounds 1–8 against the subterranean termite, Reticulitermes speratus Kolbe, were evaluated. Compounds 1 and 3 showed potent termicidal activity, and 5 and 8 showed potent antifeedant activity. Compound 1 was found to be one of the representative bioactive compounds in the n-hexane extract of T. distichum cones. Compounds 1–8, with the exception of 7, were oxides of ferruginol (9). Therefore, the presence of various oxidation forms of the abietane-type structure reflects their various bioactivities. 相似文献
999.
Yuichi Mitsutake Masanori Monde Kengo Shigetaka Shigeru Tsunokake Tatsuya Fuura 《亚洲传热研究》2008,37(3):165-183
Optimization of the fin layout in a metal hydride (MH) bed has been sought to enhance poor heat transmission in a hydrogen storage tank, and to obtain a maximum hydrogen absorption rate with a smaller volume of fins. Two different fin configurations, radial and circular fins, in a vertical cylindrical reactor vessel were tested with a La‐Ni‐based AB5 type hydrogen storage alloy. A two‐dimensional transient heat conduction analysis, coupled with predicted temperature and concentration of absorbed hydrogen in the bed for the exothermic hydride reaction, was used to evaluate enhancement of the hydrogen absorption time. The estimated temperature and concentration agreed within 6 K and 8.5%, respectively, with our experimental results. The effect of thickness and the spacing and shape of fins on the hydrogen absorption time were analytically evaluated, so that the optimum range of the each fin layout was obtained by the trade off between absorption time and reduction in the MH volume due to the volume occupied by fins. The hydrogen absorption time for the recommended layout of circular fins was reduced to approximately one‐third of that without fins. © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res, 37(3): 165–183, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20195 相似文献
1000.
Kazuya Shimoda Tatsuya HinokiHirotatsu Kishimoto Akira Kohyama 《Composites Science and Technology》2011,71(3):326-332
We report the enchanced in situ performances of tensile strength and thermal conductivity at elevated temperatures of the PCS-free SiC/SiC composite with a high fiber volume fraction above 50% fabricated by NITE process for nuclear applications. The composite was fabricated by the optimized combination of the fiber coating, the matrix slurry and the pressure-sintering conditions, based on our previous composites’ study history. The composite showed the excellent tensile strength up to 1500 °C, that it retained approximately 88% of the room-temperature strength. Also, the thermal conductivity of the composites represented over 20 W/m K up to 1500 °C, which was enough high to take the advantage of the assumed design value for nuclear applications. Microstructural observation indicated that the excellent high-temperature performances regarding tensile strength and thermal conductivity up to 1500 °C were the contribution to the high densification and crystalline structure in matrix. 相似文献