全文获取类型
收费全文 | 476篇 |
免费 | 27篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 21篇 |
化学工业 | 189篇 |
金属工艺 | 17篇 |
机械仪表 | 11篇 |
建筑科学 | 12篇 |
能源动力 | 22篇 |
轻工业 | 43篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 32篇 |
一般工业技术 | 86篇 |
冶金工业 | 7篇 |
原子能技术 | 27篇 |
自动化技术 | 37篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 11篇 |
2020年 | 12篇 |
2019年 | 14篇 |
2018年 | 20篇 |
2017年 | 13篇 |
2016年 | 21篇 |
2015年 | 13篇 |
2014年 | 10篇 |
2013年 | 46篇 |
2012年 | 17篇 |
2011年 | 28篇 |
2010年 | 25篇 |
2009年 | 29篇 |
2008年 | 27篇 |
2007年 | 16篇 |
2006年 | 23篇 |
2005年 | 24篇 |
2004年 | 12篇 |
2003年 | 16篇 |
2002年 | 13篇 |
2001年 | 11篇 |
2000年 | 7篇 |
1999年 | 8篇 |
1998年 | 6篇 |
1997年 | 11篇 |
1996年 | 11篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 6篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有506条查询结果,搜索用时 0 毫秒
461.
Effect of addition of salt on the viscometric behavior of the dilute or concentrated aqueous solution of hydroxypropyl cellulose (HPC) was determined by means of an Ubbelohde or a cone-plate viscometer. That effect on the turbidity of the dilute system was also determined. As salts, NaCl, LiCl, and thiourea were chosen. The turbidity and viscometric behavior for the dilute system, and the viscometric behavior for the concentrated system were greatly affected by salt type and concentration. With increasing NaCl or LiCl concentration, the cloud point decreased, [η] showed a maximum, Huggins' constant k′ showed a minimum, and the shear viscosity for concentrated isotropic solutions showed a maximum. The 45 wt % solution with no salt showed a viscometric behavior which was characteristic of lyotropic liquid crystals; however, with increasing NaCl concentration, a critical temperature at which the shear viscosity showed a maximum with respect to temperature shifted to lower temperature. This behavior was due to an increase in the turbidity, not due to a phase transformation. On the other hand, an addition of thiourea did not affect so greatly the turbidity and viscometric behavior as an addition of NaCl or LiCl did. We speculated different actions of NaCl and thiourea. 相似文献
462.
Summary Zwitterion bearing highly dissociable imide anion (EIm5csI) was used as major component for stable polymer electrolytes. A
polymerization of methyl acrylate in the presence of EIm5csI/LiTFSI mixture gave a flexible film with the ionic conductivity
of 9.3×10-6 Scm-1 at 50 °C. Mixing of poly(lithium acrylate) and EIm5csI/LiTFSI mixture improved ionic conductivity (3.3×10-5 Scm-1 at room temperature), lithium transference number (0.44), and thermal stability. 相似文献
463.
Wataru Aoki Yuichi Yoshino Hironobu Morisaka Keiji Tsunetomo Hirotaka Koyo Shinji Kamiya Noriyuki Kawata Kouichi Kuroda Mitsuyoshi Ueda 《Journal of Bioscience and Bioengineering》2011,111(1):16-18
Protease-targeted inhibitors have been promising pharmaceuticals. Here, we combined a yeast cell surface display system with a yeast cell chip for the high-throughput screening of protease inhibitors, and succeeded in improving the activity of a protease inhibitor. 相似文献
464.
Quasi-gel-state ionic liquid electrolyte with alkyl-pyrazolium iodide for dye-sensitized solar cells
Noriyo Ishimaru Wataru Kubo Takayuki Kitamura Shozo YanagidaYasunori Tsukahara Masato M. MaitaniYuji Wada 《Materials Science and Engineering: B》2011,176(13):996-1001
A series of non-volatile viscous ionic liquid, 1-alkyl-2-methylpyrazolium iodides (RPyI: R = C3-C7), were synthesized for the electrolyte of dye-sensitized solar cells (DSSC). Most of RPyI revealed extremely viscous quasi-gel-state electrolytes potentially preventing leakage and evaporation of electrolytes of the solar cells. A DSSC using the electrolyte composed of 1-hexyl-2-methylpyrazolium iodide (C6PyI) with iodine exhibiting higher conversion efficiency of 3.8% (under 1 Sun) for 10% larger short-circuit photocurrent, JSC, than that with a conventional ionic liquid, 1-hexyl-3-methyllimidazolium iodide (C6ImI) with iodine, in spite of less favorable viscosity (2013 mPa s (C6PyI/I2) vs. 1439 mPa s (C6ImI/I2)) for the physical diffusion of charge carriers in the electrolyte. Furthermore, the quasi-gel-state electrolytes composed of a series of RPyI ionic liquids surprisingly exhibiting comparable JSC to that with much less viscous C6ImI/I2. We discuss the results of quasi-gel-state RPyI ionic liquid electrolyte for DSSC based on the Grotthus-like electron exchange mechanism of iodide redox species in the highly viscous RPyI ionic liquid evaluated qualitatively by Raman spectroscopic observation of poly-iodide species. 相似文献
465.
Wataru Tamura Osamu Itoh Nugraha Ken Suto Jun-Ichi Nishizawa 《Journal of Electronic Materials》1999,28(7):907-911
Electroluminescence properties of PbTe pn junctions grown under various tellurium vapor pressures are investigated. For unintentionally
doped pn junctions, the luminescence bands corresponding to D-A pair and band to band transition are observed. The luminescence
intensity of the band to band transition has depended on tellurium vapor pressure, which suggests nonradiative transitions
through nonstoichiometric defects forming deep levels. For pn junctions with Bi-doped epitaxial layers, only one peak appears
at 20∼25 meV below band to band-transition energy, which, probably, shows recombination through impurity levels or impurity
band originating from Bi-doping. 相似文献
466.
Wataru Takashima Megumi Nakashima Hikaru Hashimoto Kazuo Tominaga Keiichi Kaneto 《Thin solid films》2009,518(2):674-1099
pH effect on the electrochemical deformation of freestanding polyaniline (PANi) film was investigated by means of electrochemomechanical deformation (ECMD) measurement. The maximum anodic expansion was found in PANi at around pH = 1.5 in aqueous acid consisted of HCl and NaCl. The deformation vs. redox charge (D−Q) plots revealed the critical differences in the deformation characteristics below and above pH = 1.5. The similar pH dependences were also observed in other acidic media. Against these results, we investigated the surface coating effect of PANi film on deformation behaviors. It was revealed that the PPy coating on PANi film successfully reduced the pH dependence of the PANi/PPy film deformation. The results indicate that the buffer layer coated on the PANi film surface decreases the ion concentration effects on the PANi deformation. The result indicates the extensive usage of PANi actuator in wide pH aqueous media. 相似文献
467.
Generating complicated surface with electrolyte jet machining 总被引:4,自引:0,他引:4
In the electrolyte jet machining (EJM), the electrolytic current is supplied between the anodic workpiece and the cathodic nozzle via the electrolyte which is ejected from the minute nozzle. Only the workpiece material exposed to the jet is removed due to the anodic dissolution, because the electrolytic current is restricted to the limited area by the jet. In this study, an electrolyte jet machining system which can be used to process the complicated three-dimensional surface was constructed. This system is composed of an XY stage, a rotating axis and a high-speed bipolar power supply, all of which are cooperatively controlled by a personal computer. An algorithm was developed to obtain the scanning path and speed of the nozzle to process complicated shape by superimposing simple patterns. The optimized path and speed were thus obtained so that the summation of the squared difference between the superimposed and the required patterns at every checking point becomes minimal. In order to verify the effectiveness of the developed algorithm, simulation and experiment were carried out and the machining accuracy was analyzed. The good agreement between the simulated and produced shapes with the required one proves that the algorithm meets the purpose properly. Besides, the effect of machining conditions, especially the current density on surface roughness of produced patterns was examined. It was clarified that a high current density is not only necessary to reduce machining time but also to improve the surface roughness. 相似文献
468.
469.
Hiroyuki Mochizuki Wataru Watanabe Yasuyuki Ozeki Kazuyoshi Itoh Katsumi Matsuda Satoshi Hirono 《Thin solid films》2009,518(2):714-2489
Bragg-type gratings were prepared by irradiation inside a series of optical polymers with femtosecond laser pulses and the preparation conditions of the grating were examined. Repeated scanning irradiation with femtosecond laser pulses formed gratings due to refractive index changes inside polymers. Among the polymers examined in the present study, polymethylpentene (PMP) showed the highest diffraction efficiency, which was an order of magnitude higher than those of other optical polymers. The density of PMP was the lowest among the polymers evaluated in the present study, and the large volume contraction based on its low density was responsible for the larger refractive index change of PMP. Furthermore, we fabricated large-area diffractive optical elements (DOEs) in PMP measuring 15 × 25 mm2 by widening the scanning area. 相似文献
470.
Hidetoshi Kimura Wataru Takeuchi 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(17):2817-2822
The dependence of the electronic stopping powers on the incident ions of the atomic number Z1 in the materials of carbon, aluminum, nickel, silver and gold has been evaluated by using the new Firsov formula included the Sugiyama potential for the Firsov model and the screening length with the shell effect of electrons. It was found that the calculated results based on the new Firsov formula show the experimentally well-known Z1-oscillation in the electronic stopping powers. The electronic stopping powers measured in carbon, aluminum, nickel and silver are reasonably reproduced by the new Firsov formula for the ZBL potential. 相似文献