全文获取类型
收费全文 | 792篇 |
免费 | 33篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 64篇 |
综合类 | 4篇 |
化学工业 | 250篇 |
金属工艺 | 9篇 |
机械仪表 | 12篇 |
建筑科学 | 23篇 |
能源动力 | 36篇 |
轻工业 | 89篇 |
水利工程 | 3篇 |
石油天然气 | 6篇 |
无线电 | 54篇 |
一般工业技术 | 162篇 |
冶金工业 | 12篇 |
原子能技术 | 15篇 |
自动化技术 | 89篇 |
出版年
2023年 | 4篇 |
2022年 | 13篇 |
2021年 | 15篇 |
2020年 | 8篇 |
2019年 | 9篇 |
2018年 | 11篇 |
2017年 | 18篇 |
2016年 | 16篇 |
2015年 | 11篇 |
2014年 | 14篇 |
2013年 | 39篇 |
2012年 | 45篇 |
2011年 | 37篇 |
2010年 | 48篇 |
2009年 | 43篇 |
2008年 | 43篇 |
2007年 | 37篇 |
2006年 | 30篇 |
2005年 | 32篇 |
2004年 | 37篇 |
2003年 | 29篇 |
2002年 | 24篇 |
2001年 | 21篇 |
2000年 | 14篇 |
1999年 | 13篇 |
1998年 | 18篇 |
1997年 | 18篇 |
1996年 | 11篇 |
1995年 | 8篇 |
1994年 | 12篇 |
1993年 | 7篇 |
1992年 | 11篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1986年 | 12篇 |
1985年 | 15篇 |
1984年 | 13篇 |
1983年 | 11篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1973年 | 2篇 |
排序方式: 共有828条查询结果,搜索用时 93 毫秒
1.
Joon‐Young Jun Sosuke Nakajima Koji Yamazaki Yuji Kawai Hajime Yasui Yasuyuki Konishi 《International Journal of Food Science & Technology》2015,50(4):871-877
Cystoseira hakodatensis is an unutilised brown algae belonging to family Sargassaceae. A crude methanol extract from the algae showed inhibitory effects on the growths of Bacillus cereus and Bacillus licheniformis. To isolate the major antimicrobial agent, a sequential active‐guided isolation procedure was applied: liquid–liquid extraction, column chromatography and bio‐autography. A marked antimicrobial agent (active α) was isolated in hydrophobic fraction and was determined to phenolics without carbohydrates and proteins by phytochemical test. Regarding the antimicrobial potential, the isolated active α showed better inhibitory effects against B. cereus and B. licheniformis at 2 and 4 times of lower concentrations (62.5 and 31.3 μg mL?1) in comparison with epigallocatechin gallate. These results showed that C. hakodatensis is a potential source of antimicrobial agent capable of preventing the growth of the two bacteria. 相似文献
2.
This paper describes an effective analysis of magnetic shielding based on homogenization. The analyses become time‐consuming if the problems include the magnetic substances having fine structure. The homogenization of the structure makes it possible to analyze effectively the magnetic fields. The authors introduce a method to estimate the effective permeability of the homogenized substance. This method can be applied to any periodic structure made of magnetic substance. The magnetic shielding effects by the structures against direct‐current (DC) fields generated by electric railways are analyzed by using the present method. As a result, it is found that the overhead way and the protective fence near the railway work as a magnetic shield, whose effects can be improved by appropriate arrangement of those constructions. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(4): 7–15, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20310 相似文献
3.
Yi Kai Zhou Sung Woo Choi Shigeya Kimura Shuichi Emura Shigehiko Hasegawa Hajime Asahi 《Journal of Superconductivity and Novel Magnetism》2007,20(6):429-432
GaGdN layers were grown at temperatures below 300°C by radio-frequency plasma-assisted molecular beam epitaxy on sapphire
substrates. GaGdN samples with high Gd concentration as high as 12.5% were obtained by lowering the growth temperature. X-ray
diffraction results showed no obvious secondary phase, which means that the phase separation can be suppressed by the growth
at low temperatures. All samples, including those grown at room temperature, showed ferromagnetic characteristics. Photoluminescence
emission was observed, though spectra exhibit broad and sharp luminescence bands related to many kinds of defects. It is suggested
that electrons coming from defects, especially, nitrogen vacancy, stabilize ferromagnetism, and that the carrier-induced ferromagnetism
occurs in the low-temperature-growth GaGdN. 相似文献
4.
Swelling degrees of poly(N-vinyl-2-pyrrolidone) (PVP) gel were measured in aqueous salt solutions and in water/organic solvent mixtures to find marked ion- and solvent-specificities. In order to investigate any correlation of those specificities with hydration or solvation of PVP, IR spectra band of the CO group was monitored by means of ATR method both for PVP gel and the relevant solution systems. Dependence of the peak frequency on the swelling ratio suggested that hydration of PVP carbonyl group in deswollen gel systems is different from that in the corresponding solution systems. In the solution systems, PVP carbonyl band showed a high-wavenumber shift for deswollen systems, which can be well correlated with changes in water proton charge through ionic hydration and with Gutmann's acceptor number of organic solvents. In the deswollen gel systems, the CO band showed a low-wavenumber shift, suggesting a strong hydration or doubly hydrated state. This unexpected behavior was interpreted by assuming an intermolecular hydrogen bond of two carbonyl groups intermediated by water molecules. 相似文献
5.
Authorship and citation patterns in Management Science in comparison with operational research 总被引:1,自引:1,他引:0
The authorship and citation patterns in the journal titled Management Science (MS) are analysed. The purpose of the analysis is to examine the competitive relation of MS with OR (operational research
or operations research). The analysis is focused on the use of mathematical methods, because MS entered the management research
area by using mathematical methods developed by OR and because the use of mathematical methods in real management is facing
difficulties. The relationship of MS with information systems (IS) and organisation research (Org) is analysed in regard to
the competition of MS with OR. The analysis reveals the intermediate character of MS; that is, MS is less prone to mathematical
methods and is more inclined towards IS and Org than OR is.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
6.
In the drying of coated films with dispersed pigments, such as floppy disks, the structure of the film is formed during the drying process and depends on the drying condition. It is important to understand the structure formation during drying for the design of the dryer and die better quality of the product. We measured die drying characteristics of the film and determined the structure of dried film experimentally. A qualitative model for the structure formation during drying of the coated film is suggested. 相似文献
7.
Various liquid polybutadiene derivatives were examined as modifiers to improve the brittleness of phenolic resins. Amidated polybutadienes obtained from a maleinated polybutadiene and ammonia had the highest curing tendency when they were reacted with resole under mild conditions. The cured resins were homogeneous and the brittleness of the phenolic resins was remarkably improved. Crosslinking efficiency was closely related to the succinamic acid group of the amidated polybutadiene. Thermal behavior of the succinamic acid group was also related to the effects of curing temperature and curing time on crosslinking. From these observations, cross-condensation between the succinamic acid group of an amidated polybutadiene and resole seemed to have occurred to a great extent than the self-condensation of resole itself and oxidative crosslinking of the amidated polybutadiene. 相似文献
8.
Shintaro Nakano Nobuyoshi Saito Kentaro Miura Tatsunori Sakano Tomomasa Ueda Keiji Sugi Hajime Yamaguchi Isao Amemiya Masato Hiramatsu Arichika Ishida 《Journal of the Society for Information Display》2012,20(9):493-498
We have successfully reduced threshold voltage shifts of amorphous In–Ga–Zn–O thin‐film transistors (a‐IGZO TFTs) on transparent polyimide films against bias‐temperature stress below 100 mV, which is equivalent to those on glass substrates. This high reliability was achieved by dense IGZO thin films and annealing temperature below 300 °C. We have reduced bulk defects of IGZO thin films and interface defects between gate insulator and IGZO thin film by optimizing deposition conditions of IGZO thin films and annealing conditions. Furthermore, a 3.0‐in. flexible active‐matrix organic light‐emitting diode was demonstrated with the highly reliable a‐IGZO TFT backplane on polyimide film. The polyimide film coating process is compatible with mass‐production lines. We believe that flexible organic light‐emitting diode displays can be mass produced using a‐IGZO TFT backplane on polyimide films. 相似文献
9.
Takashi Hayashi Makoto Mihoya Iwao Yamai Hajime Saito Shin-Ichi Hirano 《Journal of Materials Science》1987,22(4):1305-1309
Needle-like or wool-like Al2O3 whiskers can be grown on a substrate by the hydrolysis of aluminium fluoride vapour. Effects of the growth conditions on the morphology of the crystals and growth processes of the whisker were investigated, and the optimum growth condition of whiskers was examined. Adequate vapour pressure conditions of the reactant gases for the growth of the wool-like whisker were found to be
. Aluminium oxyfluoride was assumed to be the most probable intermediate species for the growth of Al2O3 whiskers. A variety of crystal morphologies are also shown and described with respect to the experimental conditions. 相似文献
10.
Effect of Composition on the Oxygen Tracer Diffusion in Transparent Yttrium Aluminium Garnet (YAG) Ceramics 总被引:1,自引:0,他引:1
Isao Sakaguchi Hajime Haneda Junzo Tanaka Takakimi Yanagitani 《Journal of the American Ceramic Society》1996,79(6):1627-1632
The grain boundary structure and oxygen tracer diffusion in transparent yttrium aluminum garnet (YAG) ceramics varying from 2% excess of Y2 O3 to 0.5% excess of Al2 O3 were studied. The characterization of the specimens is as follows: (i) For the Y2 O3 -excess specimen, a second phase (yttrium aluminum perovskite: YAP) containing silicon in the grain boundary was found, (ii) For the Al2 O3 -excess specimen, both aluminum-rich particles (alumina) and a silicon-rich segregant layer were observed in the grain boundary. The volume diffusion of the oxygen tracer is little influenced by the excess composition. In contrast, the grain boundary diffusion of the oxygen tracer is suppressed in the Y2 O3 -excess specimens, compared to Al2 O3 -excess specimens. These differences are thought to result from the chemical reaction between the second phase and the intergranular liquid phase during the sintering. 相似文献