全文获取类型
收费全文 | 865篇 |
免费 | 20篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 58篇 |
化学工业 | 206篇 |
金属工艺 | 43篇 |
机械仪表 | 17篇 |
建筑科学 | 18篇 |
能源动力 | 55篇 |
轻工业 | 94篇 |
水利工程 | 1篇 |
石油天然气 | 4篇 |
无线电 | 65篇 |
一般工业技术 | 184篇 |
冶金工业 | 42篇 |
原子能技术 | 17篇 |
自动化技术 | 84篇 |
出版年
2023年 | 4篇 |
2022年 | 14篇 |
2021年 | 16篇 |
2020年 | 11篇 |
2019年 | 6篇 |
2018年 | 17篇 |
2017年 | 13篇 |
2016年 | 16篇 |
2015年 | 8篇 |
2014年 | 19篇 |
2013年 | 76篇 |
2012年 | 38篇 |
2011年 | 54篇 |
2010年 | 44篇 |
2009年 | 41篇 |
2008年 | 59篇 |
2007年 | 45篇 |
2006年 | 31篇 |
2005年 | 34篇 |
2004年 | 33篇 |
2003年 | 31篇 |
2002年 | 28篇 |
2001年 | 13篇 |
2000年 | 16篇 |
1999年 | 25篇 |
1998年 | 17篇 |
1997年 | 26篇 |
1996年 | 17篇 |
1995年 | 13篇 |
1994年 | 12篇 |
1993年 | 11篇 |
1992年 | 9篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 10篇 |
1988年 | 8篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有888条查询结果,搜索用时 0 毫秒
101.
102.
103.
104.
Determination of optimal sending voltage profile in distribution systems with distributed generators
Yasuhiro Hayashi Junya Matsuki Ryoji Suzuki Eiji Muto 《Electrical Engineering in Japan》2007,161(2):16-24
Sending voltage profile of distribution feeder is controlled by changing a tap of distribution transformer. In a distribution network with distributed generators, for reasons of effect of reversed flows from them and existence of a great number of sending voltage profile candidates, it is not easy to control sending voltage profile within the acceptable voltage limit. In this paper, in order to determine the optical sending voltage profile of distribution transformer in a distribution network with distributed generators, the authors propose a new method to determine the optimal sending voltage profile so as to minimize the total number of tap position's change per day under constraints of acceptable voltage limit. In the proposed method, after calculating acceptable range of three‐phase voltage of distribution feeder, the optimal profile of tap position within the calculated acceptable voltage range is determined among these candidates by using reduced ordered binary decision diagram (ROBDD) which is an efficient enumeration algorithm. In order to check the validity of the proposed method, numerical simulations are carried out for a distribution network model with a distributed generator. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(2): 16–24, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20393 相似文献
105.
The spatial distribution of Zn2+ during galvanic corrosion of a model Zn/steel couple in 0.01 M NaCl was investigated using a scanning zinc disk electrode. The couple had a coplanar arrangement of a steel substrate with an electroplated zinc layer at the center. During galvanic corrosion, the marked changes in the Zn2+ concentration were confined to a thin solution layer ca. 1.0 mm thick above the couple surface. In this thin solution layer above the zinc layer, a higher concentration region of Zn2+ in the range of 5-18 mM extended around the zinc layer in the solution during galvanic corrosion. Conversely, above the steel surface distant from the zinc layer, the surface concentration of Zn2+ was almost zero during galvanic corrosion. On this surface, the precipitation of zinc corrosion products due to the hydrolysis reaction of Zn2+ was observed. The distribution of the Zn2+ concentration supported that Zn2+ acted as a buffer that suppressed the increased pH due to the cathodic reaction on the steel surface near the zinc layer and almost no corrosion products formed there. The spatial distribution of Zn2+ is discussed in relation to the distributions of potential and pH and the surface morphology of the galvanic couple. 相似文献
106.
Samia Tabassum Eiji Yamasue Hideyuki Okumura Keiichi N. Ishihara 《Journal of Materials Science: Materials in Electronics》2014,25(11):4883-4888
Al-doped ZnO (AZO) thin film, which possess the advantages of low cost, low sheet resistance and high transmittance, are one of the most promising candidates to replace indium tin oxide films as the transparent electrode. However, oxidation causes a substantial increase in the sheet resistance of AZO film after exposing in ambient and especially, damp heat environment. In this work, we compare structural, optical, electrical properties and environmental stability between films prepared by two different methods: sol–gel and rf sputtering. Experimental results indicate that the properties of film can be affected by different deposition method. From the X-ray diffraction analysis, all films have hexagonal wurtzite crystal structure with different preferable orientation in two different methods. Optical transmittance spectra of the AZO films exhibited transparency higher than about 80 % within the visible wavelength region and the optical band gap (Eg) of these films was increased in sputtered film, probably due to the increase of carrier concentration. The better environmental stability was found in AZO film prepared by sputtering method. Improved surface morphology and enhancement of crystal orientation (110) was considered for this improvement. 相似文献
107.
Liquid Crystals: Liquid‐Crystalline Electrolytes for Lithium‐Ion Batteries: Ordered Assemblies of a Mesogen‐Containing Carbonate and a Lithium Salt (Adv. Funct. Mater. 8/2015) 下载免费PDF全文
108.
Hiromi Nakano Motohiro Yamada Masahiro Fukumoto Eiji Yamaguchi 《Journal of Thermal Spray Technology》2011,20(3):407-411
Cold spraying has been developed as a high-quality coating technique. In this article, copper is deposited on an AlN substrate
coated by the sputtering of titanium and copper at a low pressure of less than 1.0 MPa, making this approach suitable for
a wide range of engineering applications. In order to understand the adhesion mechanism at the atomic scale, the interfacial
regions are carefully observed in thin foil samples from the cross sections of the specimens with a HREM. We find a unique
wavy boundary between the sputtered titanium and the sputtered copper. It is assumed that the shear-instability phenomenon
occurs due to the cold-spraying process and influences the adhesive strength. Furthermore, the cold-sprayed copper particles
are connected directly without any oxidation layer due to the appearance of new metallic surfaces during the impact process.
The TEM data clearly reveal the phenomena and mechanisms related to the impact of powder sprayed on the substrate. 相似文献
109.
Shizuo Saitoh Hirofumi Daiguji Eiji Hihara 《International Journal of Heat and Mass Transfer》2007,50(25-26):5215-5225
A Chen-type correlation for flow boiling heat transfer of R-134a in horizontal tubes was modified taking into account the effect of tube diameter. The effect of tube diameter on flow boiling heat transfer coefficient was characterized by the Weber number in gas phase. Results showed that this correlation could be applied to a wide range of tube diameters (0.5–11-mm-ID). In addition, the dryout point and the heat transfer characteristics after the dryout point were also investigated based on the annular flow model. The proposed experimental expressions to predict both the dryout quality and the post-dryout heat transfer coefficient could also be applied to a wide range of tube diameter (0.5–11-mm-ID). 相似文献
110.
Shizuo Saitoh Chaobin DangYoshitaka Nakamura Eiji Hihara 《International Journal of Refrigeration》2011,34(8):1846-1853
The flow boiling heat transfer coefficient of the low-GWP (global warming potential) refrigerant HFO-1234yf inside a smooth small-diameter horizontal tube (inner diameter: 2 mm) was experimentally investigated. The local heat transfer coefficient was measured at heat fluxes of 6-24 kW m−2, mass fluxes of 100-400 kg m−2 s−1, an evaporating temperature of 288.15 K, and an inlet vapor quality of 0-0.25. The results show that the effect of heat flux on the heat transfer was large at low vapor quality, while the effect of mass flux was large at high vapor quality. The heat transfer coefficient of HFO-1234yf was almost the same as that of R-134a. The heat transfer coefficients calculated based on correlations with Saitoh et al. agreed well with the measured values compared to other correlations. The measured pressure drop agreed well with that predicted by the Lockhart-Martinelli correlation. 相似文献