全文获取类型
收费全文 | 523篇 |
免费 | 15篇 |
专业分类
电工技术 | 16篇 |
化学工业 | 110篇 |
金属工艺 | 4篇 |
机械仪表 | 15篇 |
建筑科学 | 1篇 |
能源动力 | 18篇 |
轻工业 | 26篇 |
水利工程 | 1篇 |
无线电 | 51篇 |
一般工业技术 | 146篇 |
冶金工业 | 95篇 |
原子能技术 | 28篇 |
自动化技术 | 27篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 8篇 |
2013年 | 14篇 |
2012年 | 9篇 |
2011年 | 20篇 |
2010年 | 18篇 |
2009年 | 18篇 |
2008年 | 17篇 |
2007年 | 22篇 |
2006年 | 18篇 |
2005年 | 12篇 |
2004年 | 7篇 |
2003年 | 17篇 |
2002年 | 15篇 |
2001年 | 18篇 |
2000年 | 14篇 |
1999年 | 12篇 |
1998年 | 54篇 |
1997年 | 27篇 |
1996年 | 18篇 |
1995年 | 17篇 |
1994年 | 10篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1990年 | 9篇 |
1989年 | 9篇 |
1988年 | 11篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 8篇 |
1975年 | 3篇 |
1972年 | 3篇 |
1965年 | 2篇 |
排序方式: 共有538条查询结果,搜索用时 15 毫秒
51.
Masayoshi Kamiya Hiroaki Ikeda Shigenobu Shinohara 《International Journal of Communication Systems》2001,14(5):477-485
This paper describes a low‐cost version of a full‐duplex optical fibre analogue/digital data transmission link whose practical implementation is simplified by using a pair of laser diodes, each having a built‐in photodiode for monitoring the laser output power, and its application to vibration test data transmission. The transmission link sends digital data of up to 9600 bps in one direction, and analogue data of DC to 100 kHz and image data specified by an NTSC colour video signal in the opposite direction, all at the same time through one GI optical fibre. Being simple in configuration and stable against noise, this type of link has a variety of applications within factory, home and offices. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
52.
H. Sato K. Fukutani W. Futako T. Kamiya C. M. Fortmann I. Shimizu 《Solar Energy Materials & Solar Cells》2001,66(1-4)
Narrow band gap (1.5 eV) hydrogenated amorphous silicon (a-Si:H) were fabricated by a chemical annealing technique using noble gases (Ar, He, Ne). Although hydrogen content in the film was reduced to 1 atm% and band gap was decreased to 1.52 eV, high photoconductivity and large mobility–lifetime products were maintained and no marked changes in the short-range structure was found. Using these narrow band gap a-Si:H for photoactive layer in n-i-p solar cells, reasonable photovoltaic performances were obtained, i.e., open-circuit voltage of 0.71 V and fill factor of 57%. Also enhanced red response was observed with the 1.58 eV band gap i-layer solar cell prepared on textured substrate. 相似文献
53.
54.
By an immunomagnetic-bead (IMB) separation technique, isolation of Helicobacter pylori from gastrointestinal and fecal samples of gnotobiotic mice infected with the microorganism was tried. The isolation rate of H. pylori from stomach samples after IMB separation was not higher than that of direct culture of the samples. After IMB separation of feces, H. pylori was detectable by PCR, although H. pylori was not culturable. 相似文献
55.
Kin Kiong Lee Ishida Y. Ohshima T. Kojima K. Tanaka Y. Takahashi T. Okumura H. Arai K. Kamiya T. 《Electron Device Letters, IEEE》2003,24(7):466-468
We present results of the enhancement mode, n-channel 3C-silicon carbide (SiC) MOSFETs fabricated on homoepitaxy 3C-SiC films. The fabricated devices exhibit excellent gate-controlled linear and saturation regimes of operation. The average effective channel mobility is found to be 229 cm/sup 2//Vs. The breakdown field of the gate oxide is observed at be 11 MV/cm and the subthreshold swing is determined to be 280 mV/decade. 相似文献
56.
To investigate the relationship between postprandial electrogastrographic changes and parasympathetic nervous activity, 10 healthy adult males (20 to 29 years old) volunteered for EGG recording in the following conditions: 1) butylscopolamine bromide (scopolamine) administration to block parasympathetic nervous activity; 2) after food intake; and 3) during a postprandial period after the parasympathetic blockade. Power spectral analysis of EGG was performed according to Akaike's autoregressive model. When the parasympathetic nervous activity was blocked, there were no changes in the dominant frequency of the EGG. During the postprandial period, the dominant frequency in EGG increased significantly, and postprandial dip (transient frequency decrease after the food intake) was observed in 8 of the 10 subjects. During the postprandial period after scopolamine administration, the dominant frequency of EGG did not increase, and postprandial dip was observed in only two subjects. These results suggest that the parasympathetic nervous activity is involved in occurrence of postprandial gastric motor function and postprandial electrogastrographic changes. 相似文献
57.
58.
An attempt was made to carry out the following photochemical reaction, 2Fe2+ + I?3 + light → 2Fe3? + 3I? in concentrated phosphoric acid in order to obtain hydrogen iodide as a gaseous product. By means of the above photochemical, and two other consecutive chemical reactions, water is decomposed into hydrogen and oxygen. Compared to the water-splitting system with dilute sulfuric acid, this system has an advantage of easy separation of hydrogen iodide from the reaction mixture. Experiments are made with various conditions of phosphoric acid, temperature, light intensity and concentrations of iodine. 相似文献
59.
T. Ohta S. Asakura M. Yamaguchi N. Kamiya N. Gotgh T. Otagawa 《International Journal of Hydrogen Energy》1976,1(2):113-116
A hybrid thermochemical water-splitting cycle using solar energy is proposed and experimental results are presented. The cycle consists of a photochemical reaction conducted in a flat cell with a Fresnel lens and concentrating the remaining solar energy on a thermoelectric generator which produces electric power for the electrolysis steps. The photochemical reaction is: The overall efficiency is estimated to be as high as 15–25%. 相似文献
60.