全文获取类型
收费全文 | 486篇 |
免费 | 4篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 35篇 |
化学工业 | 175篇 |
金属工艺 | 12篇 |
机械仪表 | 22篇 |
建筑科学 | 8篇 |
能源动力 | 20篇 |
轻工业 | 40篇 |
水利工程 | 1篇 |
无线电 | 18篇 |
一般工业技术 | 105篇 |
冶金工业 | 7篇 |
原子能技术 | 18篇 |
自动化技术 | 31篇 |
出版年
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 15篇 |
2020年 | 6篇 |
2019年 | 6篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 11篇 |
2014年 | 24篇 |
2013年 | 31篇 |
2012年 | 22篇 |
2011年 | 34篇 |
2010年 | 17篇 |
2009年 | 16篇 |
2008年 | 26篇 |
2007年 | 19篇 |
2006年 | 22篇 |
2005年 | 23篇 |
2004年 | 20篇 |
2003年 | 20篇 |
2002年 | 17篇 |
2001年 | 8篇 |
2000年 | 9篇 |
1999年 | 13篇 |
1998年 | 14篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 9篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 7篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1974年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有492条查询结果,搜索用时 15 毫秒
91.
Keiichi Shibata 《Journal of Nuclear Science and Technology》2017,54(2):147-157
Neutron nuclear data on 10 isotopes of platinum have been evaluated for the next version of Japanese Evaluated Nuclear Data Library general-purpose file in the energy region from 10?5 eV to 20 MeV. Resolved resonance parameters of naturally occurring isotopes were taken from a compilation work, while unresolved resonance parameters were obtained by fitting to the total and capture cross sections calculated from nuclear models. A statistical model code was applied to evaluate cross sections above the resolved resonance region. Compound, pre-equilibrium and direct-reaction processes were considered for cross-section calculation. Coupled-channel optical model parameters were employed for the interaction between neutrons and nuclei. Giant-dipole and pygmy resonance parameters for E1 γ-ray transition from platinum isotopes were determined so as to reproduce measured γ-ray spectrum. The present results reproduce experimental data very well. The evaluated data are compiled into Evaluated Nuclear Data File formatted data files. 相似文献
92.
Hirohisa Narita Keiichi Shirase Eiji Arai Keiichi Nakamoto Lian-Yi Chen Hideo Fujimoto 《国际生产研究杂志》2013,51(17):3657-3673
In order to satisfy the recent various consumers’?needs, an advanced manufacturing system will be required. So, the innovative concept of Future Oriented Machine Tools (FOMT), which consists of four function blocks to realize the advanced manufacturing system, is proposed. The four function blocks are Management, Prediction, Observation and Strategy, and intelligent manufacturing processes are realized by utilizing these function blocks. FOMT can make a significant contribution in four stages: design stage, production scheduling stage, machining stage and post-machining stage. In the design stage, the product information such as accuracy can be evaluated in CAD, considering the manufacturing ability concurrently. In the production scheduling stage, the product schedules can be generated automatically and flexibly for the various products. In the machining stage, cutting conditions adjusted autonomously according to the machining status and machining problems. In the post-machining stage, the machining know-how data are accumulated and stored for future production and human engineers. The feasibility of it, especially the machining stage, is discussed using the developed cutting process simulator called VMSim (virtual machining simulator) from the view points of cutting force, machining error and environmental burden (CO2 emission). 相似文献
93.
We investigated the surface potential built across the electrode/fullerene (C60) or copper phthalocyanine (CuPc) interface and C60/CuPc interface as a function of the thickness of the semiconductor film in the dark condition and under illumination. The surface potential of C60 on Au, Al and Mg changes negatively with the increment of film thickness and it saturates at − 0.25, − 1.0 and − 1.5 V within 20 nm. The Fermi level alignment at C60/electrode interface is established within ∼ 20 nm from electrode, and very high electric field exists due to the displacement of negative electronic charges from electrode into C60. On the other hand, the surface potential of CuPc on ITO changes to + 0.1 V, and the work functions of C60 and CuPc were estimated as 5.0 eV and 4.7 eV. C60 film also accepts electrons from CuPc at hetero-junction interface, and the Fermi-level alignment was again obtained at C60/CuPc interface under illumination. The built-in potential of ca. 0.3 V formed at C60/CuPc interface was considered as the origin of the reduction of open-circuit voltage in ITO/CuPc/C60/Au device compared with the optimum value of 0.6 V. On the other hand, the very high electric field formed at C60/Mg contact improved the photovoltaic properties. 相似文献
94.
95.
Kazuhiko Kato Takeshi Hibino Keiichi Komoto Seijiro Ihara Shuji Yamamoto Hideaki Fujihara 《Solar Energy Materials & Solar Cells》2001,67(1-4)
Authors have evaluated the life cycle of a thin-film CdS/CdTe PV module to estimate the energy payback time (EPT) and the life-cycle CO2 emissions of a residential rooftop PV system using the CdS/CdTe PV modules. The primary energy requirement for producing 1 m2 of the CdS/CdTe PV module was similar to a-Si PV module at annual production scale of 100 MW. EPT was calculated at 1.7–1.1 yr, which was much shorter than the lifetime of the PV system and similar to that of a-Si PV modules. The life-cycle CO2 emissions were also estimated at 14–9 g-C/kWh, which was less than that of electricity generated by utility companies. 相似文献
96.
Hyun Soon Park Yasukazu Murakami Keiichi Yanagisawa Tsuyoshi Matsuda Ryosuke Kainuma Daisuke Shindo Akira Tonomura 《Advanced functional materials》2012,22(16):3434-3437
Peculiar magnetic domain walls produced in Heusler alloys, which have attracted renewed interest due to their potential application to actuators and spintronic devices, are studied here using electron holography. The observations reveal unexpectedly narrow magnetic domain walls, the width of which showed perfect agreement with that of the antiphase boundaries (APB, e.g., only 3 nm). While the results can be explained by the significant depression of ferromagnetism due to the local chemical disorder, the electron phase shift indicates that ferromagnetic correlation still remains in the APB region. 相似文献
97.
Imoto Taiji; Ueda Tadashi; Tamura Tomohiro; Isakari Yoshimasa; Abe Yoshito; Inoue Makoto; Miki Takeyoshi; Kawano Keiichi; Yamada Hidenori 《Protein engineering, design & selection : PEDS》1994,7(6):743-748
Mutations around His15 which lie far away from the active site,stimulated glycol chitin activity of lysozyme at physiologicaltemperature. Del-Argl4Hisl5 lysozyme, a mutant lysozyme whoseArgl4 and Hisl5 were deleted together, and has the highest activityamong these mutant lysozymes, had a similar binding abilityto a trimer of N-acetyl-glucosamine, a substrate analogue, relativeto native lysozyme. This suggests that the increased activitywas due to an increased kcat in the catalysis reaction. TheH-D exchange rate of the N-1 proton in the Trp63 which is locatedin the active site cleft, was enhanced in the Del-Argl4Hisl5lysozyme, while 2-D proton NMR analysis revealed no conformationalchange around Trp63. We conclude that some sort of fluctuationat the active site might be required for the manifestation ofactivity. This theory is supported by the finding that the Del-Argl4Hisl5lysozyme showed a shift in temperature dependency of activityto lower temperatures compared with that of native lysozyme. 相似文献
98.
Prevaporation through the PVA membrame containing β-cyclodextrin oligomer (PVA/CD membrane) was performed for the mixtures of water/ethanol, water/1-propanol, and water/2-propanol. At higher alcohol concentrations, the water selectivities were greatly increased by CD for all the mixtures, in the order of 2-propanol/water>1-propanol/water>ethanol/water. The water permeation rate was decreased by CD, and the alcohol permeation rate was decreased much more for each mixture. At lower alcohol concentrations, the water selectivity for 1-propanol/water was slightly increased by CD, and that for 2-propanol/water was scarcely affeted, whereas that for ethanol/water was greatly increased. The water permeation rate was increased by CD for each mixture, and the relative increases in the water rates for propanols/water were smaller than that for ethanol/water. The permeation rate of 1-propanol as well as that of ethanol was decreased by CD, but the rate of 2-propanol was was increased. These effects of CD can be explained in terms of the inclusion strength. © 1994 John Wiley & Sons, Inc. 相似文献
99.
Keiichi Tomishige Osamu Yamazaki Yangguang Chen Kota Yokoyama Xiaohong Li Kaoru Fujimoto 《Catalysis Today》1998,45(1-4):35-39
Carbon deposition behavior in CO2 reforming of methane, methane decomposition, and CO disproportionation on nickel-magnesia solid solution was investigated by means of thermogravimetric analysis and temperature programmed reaction of deposited carbon with carbon dioxide. It was found that rapid oxidation of CHx on Ni surface by oxygen species from CO2 through dissociation at metal-support interface is a key step for the inhibition of carbon formation. 相似文献
100.
The pitch control of wind generators is usually made by a feed back control concept. However, under the conditions where a wind speed changes very frequently due to geographic reasons of the site and the target system has large rotor inertia, the feed back signal which is applied to the control system to compensate disturbance such as wind speed variations is delayed, and consequently the control strategy to keep the generated power at a constant value does not work well. If the wind speed shows too much variation, this will cause a violent variation of power and result in step out operation of the generator from the power system due to magnetic saturation. This paper proposes a control strategy to reduce the power variations by introducing feed forward control combining with the conventional feed back control. 相似文献