全文获取类型
收费全文 | 203篇 |
免费 | 3篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 15篇 |
化学工业 | 47篇 |
金属工艺 | 18篇 |
机械仪表 | 11篇 |
能源动力 | 4篇 |
轻工业 | 27篇 |
水利工程 | 2篇 |
无线电 | 16篇 |
一般工业技术 | 27篇 |
冶金工业 | 31篇 |
原子能技术 | 3篇 |
自动化技术 | 7篇 |
出版年
2023年 | 1篇 |
2021年 | 1篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 7篇 |
2010年 | 5篇 |
2009年 | 6篇 |
2008年 | 5篇 |
2007年 | 9篇 |
2006年 | 12篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 9篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 19篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 7篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 7篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 4篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1974年 | 1篇 |
排序方式: 共有208条查询结果,搜索用时 314 毫秒
111.
Fukue M Yanai M Sato Y Fujikawa T Furukawa Y Tani S 《Journal of hazardous materials》2006,136(1):111-119
The contamination of sediments can be evaluated from comparison of the current concentration with the estimated background value. Although it is known that grain size affects background concentrations, there have been difficulties in evaluating this effect. The specific surface area of sediments, which can be calculated from the grain size distribution, is introduced as a property index for correlation of background values. The results show that for sandy-to-sandy silt sediments, the background values of metals are expressed in terms of fines content, which can be correlated with the corresponding specific surface area. However, for silty clay or clayey silt sediments, which would have a high metal retention capacity, the level of the background may be constrained by the relatively low concentrations of metals in seawater. Finally, background levels of Zn, Cu and Pb are presented. 相似文献
112.
Akihide Saimoto Masaki Fujikawa Chobin Makabe Taisuke Yamanaka Muhammed Sohel Rana 《Engineering Failure Analysis》2010,17(4):838-847
The values of stress intensity factors of unsymmetrical cracks initiated from hole edges under tension were calculated in a center-holed plate, that is a plate having a hole in the center of a front face. The correction factor for stress intensity in the case of the holed plate with cracks was compared with that of a center-cracked plate whose crack length was equal to the total of the hole diameter and the lengths of the cracks in the case of the holed plate. In the present study, to understand the variation of the stress intensity factor, counterplots of the stress intensity factor KI and the correction factor FI are employed. Also, the variation of ratio RF of correction factors between the holed plate with crack and the center-cracked plate were investigated. Where non-dimensional hole diameter a/W is smaller than 0.2, the ratio RF is less than 1.1 after crack growth length c/W reaches 0.1. Where, 2a, 2c and 2W are hole diameter, the growth length of the crack from hole edge, and plate width, respectively. Therefore, the stress intensity factor for cracks initiated from a holed plate can be approximated within 10% error to that of a center-cracked plate where a/W is smaller than 0.2, though the unsymmetrical cracks are initiated from the edges. Where a/W is larger than 0.3, RF becomes larger than 1.1 in the wide range of c/W. 相似文献
113.
Toshihiko Tanaka Shinji Fujikawa Shigeyuki Funabiki 《Electrical Engineering in Japan》2003,144(2):53-62
This paper proposes a new method of damping harmonic resonance in the DC link of a large‐capacity rectifier‐inverter system, such as in rapid‐transit railways. A voltage‐source PWM converter is connected in series to the DC capacitor of the rectifier through a matching transformer, acting as a damping resistor to the DC capacitor current. No filters are needed to extract harmonic components from the DC capacitor current. This results in a quick response and highly stable damping. The relationship between the control gain of the PWM converter and the required rating is theoretically discussed. We show that the required rating is less than one‐thousandth of that previously proposed. In particular, regenerating the power consumed by the PWM converter is very important because of the large power in practical systems. Normally, an additional PWM inverter is connected to the DC bus of the PWM converter to regenerate the consumed power. The additional inverter regenerates the DC power to the AC source through a transformer. This method, however, makes the damping circuit complex, thus the proposed method for the DC‐link harmonic resonance is less practicable. In this paper, a simple and novel scheme that utilizes the DC‐link voltage of the rectifier as a DC source for the PWM converter is proposed. The excellent practicability of the proposed damping method with the novel regenerating scheme is confirmed using digital computer simulation. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(2): 53–62, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10172 相似文献
114.
Akiko Katayama-Aramata Hiroshi Nakajima Keikichi Fujikawa Hideaki Kita 《Electrochimica acta》1983,28(6):777-780
The electrochemical characteristics of a platinum electrode directly bonded to one side of a solid polymer electrolyte membrane (Pt-SPE) were studied. Current-potential relations of hydrogen and oxygen adsorbed on Pt-SPE were observed to be similar to those on a platinum metal electrode independently of the presence/absence of electrolytic solution at the platinum side of Pt-SPE. Hydrogen evolution, hydrogen ionisation, and oxygen reduction were examined at the condition that the side at the platinum of Pt-SPE was free from liquid but filled with the gases concerned 相似文献
115.
116.
Katsuhiro Fujikawa 《Microprocessors and Microsystems》1981,5(8):351-356
The application of the microcomputer to various industrial machinery or equipment is expanding. The sewing industry is no exception to this trend, positively employing microcomputers for more advanced automation, labour saving and further industrialization. To satisfy recent needs, a sewing machine motor equipped with eddy current variable-speed clutch, LIMI-STOP Z, was developed. The LIMI-STOP Z features, besides a friction-free low inertial clutch used instead of the conventional friction type clutch, the use of a 4-bit microcomputer in the control system. This paper describes the principle, composition and functions of the LIMI-STOP Z. 相似文献
117.
High voltage power transistors were produced using epitaxially grown Si wafers which contain many stacking faults in base region. The reverse biased characteristics of the emitter-base and the base-collector junctions of these transistors showed “soft” breakdown under a sufficiently high reverse bias. A detailed analysis of the effect by stacking faults was carried out with a scanning electron microscope (SEM). It was observed that the junctions of the transistors are not uniform by the stacking faults. 相似文献
118.
119.
Yuji?ShimadaEmail author Yomi?Watanabe Akiko?Kawashima Kengo?Akimoto Shigeaki?Fujikawa Yoshio?Tominaga Akio?Sugihara 《Journal of the American Oil Chemists' Society》2003,80(1):37-42
A single-cell oil from a Mortierella alpina mutant (TGM17 oil) contains n−9 PUFA: 14.3 wt% 6,9-octadecadienoic acid (18∶2n−9; n−9 LnA) and 17.1 wt% Mead acid (20∶3n−9;
MA). Lipase screening indicated that Pseudomonas aeruginosa lipase acted strongly on n−9 LnA and weakly on MA, and Candida rugosa lipase acted weakly on the two PUFA. Hence, fractionation and enrichment of the two FA were conducted with the lipases. The
first step was selective hydrolysis of IGM17 oil with P. aeruginosa lipase. The hydrolysis fractionated the oil into FFA containing 20.4 wt% n−9 LnA and 6.3 wt% MA, and acylglycerols containing
10.7 wt% n−9 LnA and 23.7 wt% MA. The FFA fraction was used for preparation of n−9 LnA-rich FFA. After removal of saturated
FA, the FFA were esterified with lauryl alcohol (LauOH) using C. rugosa lipase. Two selective esterifications increased the n−9 LnA content to 54.0 wt% with 38.2% recovery of the initial content
of TGM17 oil. The acylglycerol fraction obtained in the hydrolysis with P. aeruginosa lipase was used for preparation of MA-rich FFA. The acylglycerol fraction was hydrolyzed under alkaline conditions, and saturated
FA were eliminated by urea adduct fractionation. Two selective esterifications of the FFA with LauOH increased the MA content
to 60.2 wt% with 53.5% recovery. Thus, the two-step enzymatic process was effective for fractionation and enrichment of n−9
LnA and MA. 相似文献
120.
本文讨论了有关金属及合金屈服强度的若干问题,包括: 1.滑移和位错; 2.位错的增殖; 3.范性流变速率方程; 4.派尔斯(Peierls)应力; 5.温度对屈服强度的影响; 6.溶质原子的影响。 相似文献