全文获取类型
收费全文 | 462篇 |
免费 | 8篇 |
专业分类
电工技术 | 31篇 |
综合类 | 1篇 |
化学工业 | 170篇 |
金属工艺 | 6篇 |
机械仪表 | 12篇 |
建筑科学 | 9篇 |
能源动力 | 17篇 |
轻工业 | 39篇 |
水利工程 | 1篇 |
无线电 | 19篇 |
一般工业技术 | 90篇 |
冶金工业 | 7篇 |
原子能技术 | 21篇 |
自动化技术 | 47篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 11篇 |
2021年 | 9篇 |
2020年 | 6篇 |
2019年 | 10篇 |
2018年 | 6篇 |
2017年 | 12篇 |
2016年 | 9篇 |
2015年 | 4篇 |
2014年 | 19篇 |
2013年 | 31篇 |
2012年 | 27篇 |
2011年 | 33篇 |
2010年 | 26篇 |
2009年 | 23篇 |
2008年 | 27篇 |
2007年 | 20篇 |
2006年 | 22篇 |
2005年 | 12篇 |
2004年 | 11篇 |
2003年 | 16篇 |
2002年 | 18篇 |
2001年 | 7篇 |
2000年 | 11篇 |
1999年 | 14篇 |
1998年 | 12篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 8篇 |
1994年 | 7篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有470条查询结果,搜索用时 15 毫秒
41.
Design criteria for gas entrainments (GE) from the liquid surface in a fast breeder reactor system were proposed in this paper for the two types of GE phenomena from a vortex dimple based on a computational fluid dynamics (CFD) method. The first gas entrainment phenomenon is a gas core extension directly to the outlet piping level, which induces large amount of GE to the flow system. The second is continuous bubble detachments from the tip of the vortex dimple. Based on CFD calculations for elemental experiments of the surface vortex, local CFD non-dimensional numbers were defined as the design criteria to prevent GE. In conclusion, it was found that the CFD non-dimensional numbers are useful for the design parameters of GE prevention. 相似文献
42.
Masaru Hoshiya Takaaki Nakamura Tomoya Mochizuki 《Canadian Metallurgical Quarterly》2004,130(7):780-785
Since cash flow of asset in the long run is generally subject to economic fluctuation, and also to potential damage due to seismic hazard risk, asset pricing is more relevantly evaluated, provided that uncertainties of both cash flow and seismic risk are properly taken into account. This study will propose a discounted cash flow method to evaluate asset pricing, in which incomes gained from asset are modeled as a Markov process and seismic loss is modeled due to only one earthquake event during the service time. A numerical example is demonstrated for an 11 story steel reinforced commercial building considering the service time of 50 years. Various risk–asset price curves are numerically obtained in the form of probability of excess versus asset price with discount rate as a parameter for cases with and without earthquake loss taken into account, and for a case in which earthquake strengthening measure is implemented. These curves contribute information to decision makers in charge of risk and investment management. 相似文献
43.
Takaaki Koyanagi Takashi Nozawa Yutai Katoh Lance L. Snead 《Journal of the European Ceramic Society》2018,38(4):1087-1094
For the development of silicon carbide (SiC) materials for next-generation nuclear structural applications, degradation of material properties under intense neutron irradiation is a critical feasibility issue. This study evaluated the mechanical properties and microstructure of a chemical vapor infiltrated SiC matrix composite, reinforced with a multi-layer SiC/pyrolytic carbon–coated Hi-NicalonTM Type S SiC fiber, following neutron irradiation at 319 and 629?°C to ~100 displacements per atom. Both the proportional limit stress and ultimate flexural strength were significantly degraded as a result of irradiation at both temperatures. After irradiation at 319?°C, the quasi-ductile fracture behavior of the nonirradiated composite became brittle, a result that was explained by a loss of functionality of the fiber/matrix interface associated with the disappearance of the interphase due to irradiation. The specimens irradiated at 629?°C showed increased apparent failure strain because the fiber/matrix interphase was weakened by irradiation-induced partial debonding. 相似文献
44.
Fumikazu Imai Kimio Kunimori Takaaki Manabe Toshiya Kumagai Hisakazu Nozoye 《Thin solid films》1997,310(1-2):184-193
We synthesized titanium oxide thin films on MgO(100) single-crystal substrates by two reactive deposition methods and compared the structures of the thin films formed by these methods. In one method (pulsed-molecular-beam deposition method), molecular oxygen is supplied to the substrates by using a pulsed-molecular-oxygen beam source and deposition of one unit layer of titanium and subsequent supply of molecular oxygen are repeatedly performed. In the other method (radical beam deposition method), atomic oxygen is irradiated to the substrates by using an atomic oxygen beam generated by the radical beam source and irradiation of the atomic oxygen and deposition of titanium are simultaneously performed. In the case of the pulsed-molecular-beam deposition method, the crystal structure was changed by increasing the number of oxygen pulses supplied from the beam source. We found that the crystal structure of titanium oxide depended on the composition ratio of O:Ti in the film. The maximum ratio of O:Ti attainable by this method was 1.85, and at this ratio, (100)-oriented pseudorutile was formed. In the case of the radical beam deposition method, (100)-oriented anatase was formed below the titanium deposition rate of 0.10 nm/s and pseudorutile (TiO2−δ) was formed above 0.15 nm/s. The pseudorutile structure synthesized on this experiment was very stable in air. We concluded that the crystal structure of the pseudorutile is a new crystal structure of titanium oxide. 相似文献
45.
Yoshihiko Nakata Satoshi Ninomiya Chikage Imada Masafumi Nagai Takaaki Aoki Jiro Matsuo Nobutsugu Imanishi 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2005,230(1-4):489-494
We have measured both secondary neutral and ionized particles from an InSb target under 3.0 MeV Si ion bombardment. Measurements of both ions and neutrals have not been carried out so far in the MeV-energy range. The mass spectra and axial emission energy distributions of secondary particles were investigated. Secondary ions were measured with a linear- and a reflective-type time-of-flight technique, whereas secondary neutral particles were photo-ionized by a UV pulsed laser (ArF: 193 nm) and measured with a reflective-type time-of-flight technique. Different results were obtained for neutral particles in comparison with ionized particles. The mean energy of neutral Sb atoms was much lower than that of neutral In atoms, whereas the mean energies of secondary In and Sb ions were nearly equal. 相似文献
46.
Hirofumi Kakemoto Tohru Higuchi Hajime Shibata Satoshi Wada Takaaki Tsurumi 《Journal of Materials Science: Materials in Electronics》2008,19(4):311-314
The modification of thermoelectric figure of merit was estimated from enhanced mobility of [100] oriented beta-FeSi2 film. beta-FeSi2 on Si(001) substrate was prepared by molecular beam epitaxy method using an Fe source. The crystallographic orientation of
beta-FeSi2 film on Si(001) substrate was characterized by using X-ray diffraction. Using scanning electron microscopy, surface morphology
and film thickness of samples were observed and estimated, respectively. The mobility of beta-FeS2 film on Si(001) substrate were also characterized by Hall measurement at room temperature. A part of the enhancement of figure
of merit was evaluated as the functions of mobility and crystallographic orientation of samples. 相似文献
47.
Hiroyuki Mishima Mituo Kakei Toshio Yasui Saori Miyamoto Yasuo Miake Takaaki Yanagisawa 《Frontiers of Materials Science in China》2008,2(2):179-181
The present study was aimed at examining the nature of apatite crystal in the tooth apparatus of a conodont fossil using transmission
electron microscopy (TEM), scanning electron microscopy (SEM), laser Raman microprobe spectrometry and electron-probe microanalysis
(EPMA). The hard tissue of the condont consisted of 2 layers and the organization varied with the size of the crystal. Higher
magnification showed that the crystals were observed in the lattice of (100) and the central dark lines were not present.
Ca, P, and F were detected in the crystal using EPMA. Our results indicate that the apatite crystal in conodont fossils is
not hydroxyapatite but fluorapatite. 相似文献
48.
Inés S. Neira Francisco Guitián Takaaki Taniguchi Tomoaki Watanabe Masahiro Yoshimura 《Journal of Materials Science》2008,43(7):2171-2178
We report an effective method for the synthesis of hydroxyapatite whiskers with sharp faceted hexagonal shape employing a
low temperature (90 °C) hydrothermal route with calcium nitrate tetrahydrate, diammonium phosphate and urea as starting materials.
The key parameters of the synthesis process i.e. duration, temperature cycle of the treatment and starting pH value are carefully
varied and the end products are investigated using powder X-ray diffraction (XRD), Raman-scattering, infrared spectroscopy
(IR), elemental analysis, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron
microscopy (TEM), electron diffraction (ED), and high-resolution TEM (HRTEM) in order to find the optimal reaction conditions
that lead to the desired hexagonal morphology of HA whiskers. The results demonstrate that gradual and greater increase in
solution pH during the hydrothermal process favors large quantity of the single-crystalline hydroxyapatite whiskers with well
defined hexagonal morphology. 相似文献
49.
Takeshi Miura Takaaki Kaiga Takeshi Shibata Hiroaki Katsura Katsubumi Tajima Hideo Tamamoto 《IEEJ Transactions on Electrical and Electronic Engineering》2014,9(6):697-699
In this paper, we propose a novel method to extract keyframes from motion capture data. A hybrid approach, which combines a curve‐simplification algorithm with an initialization procedure including principal component analysis, is adopted. The developed method automatically extracts an appropriate number of keyframes at high speed without performance degradation. Experimental results prove the effectiveness of the present method. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
50.
Gang Zou Xian You Hideki Kohn Takaaki Manaka Mitsumasa Iwamoto 《Thin solid films》2009,518(2):750-753
An azobenzene mesogen-substituted diacetylene (NADA) monolayer has been transferred onto the solid substrate by the traditional Langmuir–Blodgett (LB) method. Solid-state polymerization of NADA LB films can be sensitized in visible light region. In situ UV–vis absorption measurement enables us to study polymerization kinetics of NADA LB films. The polymerization process can be described as a first order rate equation and polymerization rate constants are characterized in detail. Furthermore, achiral NADA molecules can form chiral LB films through overcrowded packing of the azobenzene moiety. 相似文献