全文获取类型
收费全文 | 269篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 14篇 |
综合类 | 2篇 |
化学工业 | 62篇 |
金属工艺 | 8篇 |
机械仪表 | 7篇 |
能源动力 | 12篇 |
轻工业 | 14篇 |
水利工程 | 1篇 |
无线电 | 17篇 |
一般工业技术 | 46篇 |
冶金工业 | 59篇 |
原子能技术 | 8篇 |
自动化技术 | 25篇 |
出版年
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 6篇 |
2020年 | 2篇 |
2019年 | 11篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 7篇 |
2014年 | 7篇 |
2013年 | 18篇 |
2012年 | 6篇 |
2011年 | 10篇 |
2010年 | 11篇 |
2009年 | 10篇 |
2008年 | 8篇 |
2007年 | 7篇 |
2006年 | 12篇 |
2005年 | 10篇 |
2004年 | 7篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 22篇 |
1997年 | 11篇 |
1996年 | 11篇 |
1995年 | 12篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1987年 | 1篇 |
1984年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1974年 | 2篇 |
排序方式: 共有275条查询结果,搜索用时 15 毫秒
1.
Y Terashima H Ozaki R R Giri T Tano S Nakatsuji R Takanami S Taniguchi 《Water science and technology》2006,54(8):55-63
Environmental pollution by low concentrations of 2,4-Dichlorophenoxyacetic acid (2,4-D) is a concern these days due to ever increasingly stringent regulations. Photocatalysis with immobilized TiO2 fiber is a promising oxidation method. Laboratory experiments on photocatalytic degradation of 0.045 mmol l(-1) 2,4-D with the world's first high-strength TiO2 fiber catalyst were carried out in a continuous flow reactor in which the degradations were, in general, similar to those with high 2,4-D concentrations investigated elsewhere. Degradation and mineralization of 2,4-D were significantly enhanced with no initial pH adjustments. The rate constants for total organic carbon (TOC) without pH adjustment were about two-fold bigger than the pH adjustment cases. CO2 gas measurement and carbon mass-balance were carried out for the first time, where about 34% organic carbon converted into CO2 gas during four-hour oxidation. 2,4-Dichlorophenol (2,4-DCP), phenol, benzyl alcohol and two unknowns (RT = 2.65 and 3.78 min.) were detected as aromatic intermediates while Phenol was the new aromatic in HPLC analysis. Dechlorination efficiencies were high (> 70%) in all the cases, and more than 90% efficiencies were observed in chloride mass balance. Bigger flow rates and solution temperature fixed at 20 degrees C without pH adjustment greatly enhanced 2,4-D mineralization. These results can be an important basis in applying the treatment method for dioxin-contaminated water and wastewater. 相似文献
2.
3.
Kentaro Terashima Suguru Tamura Sea-Hoon Kim Toshinobu Yoko 《Journal of the American Ceramic Society》1997,80(11):2903-2909
The third–order nonlinear optical susceptibility, χ(3) , of lanthanide (lanthanum, praseodymium, neodymium, and samarium) borate glasses has been measured by the third harmonic generation method. The structure of the present glass system has been studied by infrared and Raman spectroscopic methods. The network structures of the present Ln2 O3 –B2 O3 glasses have been confirmed to be basically similar to each other. Praseodymium, neodymium, and samarium borate glasses exhibit χ(3) values that are larger than lanthanum borate glasses, because of the optical resonance effect, in accordance with the f – f transition. Especially, the χ(3) value for 30Pr2 O3 ·70B2 O3 glass is 1.8 × 10−12 esu, which is a factor of ∼60 larger than that of SiO2 glass. This striking enhancement of χ(3) is mainly attributed to the large transition moment to the first excitation state. 相似文献
4.
To help corporations survive amidst worldwide quality competition, the authors have focused on the strategic development of a higher-cycled product design CAE model employing a highly reliable CAE analysis technology component model. Their efforts are part of principle-based research aimed at evolving product design and CAE development processes to ensure better quality assurance. To satisfy the requirements of developing and producing high quality products while also reducing costs and shortening development times, the effectiveness of this model was verified by successfully applying it to the technological problems of loosening bolts and other product design bottlenecks at auto manufacturers. 相似文献
5.
Xia Cao Wang Dong F. Ono Takahito Itoh Toshihiro Esashi Masayoshi 《Microsystem Technologies》2022,28(11):2443-2453
Microsystem Technologies - In this paper, a system of magnetically coupled oscillators consisting of a Π-shaped horizontal cantilever and a rectangular vertical cantilever with a frequency... 相似文献
6.
In recently developed intelligent vehicles, warning alarms are often used to prompt avoidance behaviours from drivers facing imminent hazardous situations. However, when critical reaction delays to auditory stimulation are anticipated, the alarm should be activated earlier to compensate for such delays. It was found that reaction times to an auditory stimulus significantly increased in the presence of slow eye movement (SEM), which is known to occur frequently during the wake-sleep transition. The reaction delay could not be attributed to temporal effects such as fatigue and was invariant regardless of response effectors (finger or foot). Moreover, it was found that applied pedal force decreased immediately after an auditory stimulus interrupted SEM. Consequently, it was concluded that SEM can be a good predictor of reaction delays to auditory warning alarms when drivers are in a drowsy state. STATEMENT OF RELEVANCE: The present study demonstrated that simple auditory reaction time significantly increased when SEM emerged. In the design of vehicle safety systems using warning alarms to prompt avoidance behaviours from drivers, such reaction delays during SEM must be taken into account. 相似文献
7.
Soichi Hirota Shuhei Inoue Takahito Inoue Yoshifumi Kawai Yasutaka Wada Takashi Noguchi Yukihiko Matsumura 《Korean Journal of Chemical Engineering》2016,33(4):1261-1266
Supercritical water gasification (SCWG) has attracted attention as a technology for utilizing wet biomass. We used a fluidized bed of alumina particles to prevent blockage of a SCWG reactor. A glucose solution was heated in the reactor with and without fluidized alumina particles. In the absence of alumina particles, char particles formed homogeneously in the reactor, but the use of a fluidized bed resulted in accumulation of char particles at the reactor’s exit rather than inside the reactor. Therefore, the fluidized bed was effective at preventing blockage of the reactor. However, the alumina particles did not remove deposits from the reactor’s walls. Instead, the fluidized bed caused larger char particles to form, preventing their adhesion to the reactor’s wall. 相似文献
8.
1 Introduction MEMS (MicroElectroMechanicalSystem )basedonsemiconductormicrofabricationplaysim portantrolesforexampleinthe peripheryofITsystems.NEMS (NanoElectroMechanicalSys tem)containsnano_scalestructures.Sophisticatedandhighperformancesystemsbasedonth… 相似文献
9.
Hyeonjae Kim Yeongsoo Choi Nariyasu Kanuka Hisao Kinoshita Takahito Nishiyama Takao Usami 《Applied Catalysis A: General》2009,352(1-2):265-270
Preparation of Pt-loaded TiO2 nanofibers and their catalytic performance for water gas shift (WGS) reactions have been explained in this work. The Pt-loaded TiO2 nanofibers were obtained by electrospinning poly-ethylene oxide (PEO) aqueous solutions containing Ti(OH)n slurry and Pt nanoparticles at room temperature, followed by calcination at 773 K for 4 h. The calcined nanofibers were rougher than the nanofibers of PEO/Ti(OH)n/Pt due to the PEO degradation and oxidation of Ti(OH)n to TiO2. Diameters of the Pt-loaded TiO2 nanofibers ranged between 200 and 900 nm. Catalytic activity of the Pt-loaded TiO2 nanofibers for water gas shift (WGS) reactions was evaluated and it was observed that their activity was 5–7 times higher than that of a bulk catalyst. Such improvement is attributed to the larger surface area of the nanofiber catalyst compared to that of the bulk catalyst. To the best of our knowledge, this is the first demonstration of a synthesis of Pt-loaded TiO2 nanofibers from a Ti(OH)n nanoparticle slurry using electrospinning and its application to WGS reactions. 相似文献
10.
Anodically pretreated diamond electrodes have been used for the detection of chlorophenols (CPs) in environmental water samples after high-performance liquid chromatographic (HPLC) separation. The anodization of as-deposited boron-doped polycrystalline diamond thin-film electrodes has enabled the stable determination of phenols over a wide concentration range. Prior to the HPLC analysis, a comparative study with ordinary glassy carbon, as-deposited diamond, and anodized diamond was made to examine the oxidative behavior of phenols by cyclic voltammety and flow injection analysis with amperometric detection. At anodized diamond electrodes, reproducible, well-defined cyclic voltammograms were obtained even at high CP concentration (5 mM), due to a low proclivity for adsorption of the oxidation products on the surface. In addition, after prolonged use, the partially deactivated diamond could be reactivated on line by applying a highly anodic potential (2.64 Vvs SCE) for 4 min, which enabled the destruction of the electrodeposited polymer deposits. Hydroxyl radicals produced by the high applied potential, in which oxygen evolution occurs, are believed to be responsible for the oxidation of the passivating layer on the surface. When coupled with flow injection analysis (FIA), anodized diamond exhibited excellent stability, with a response variability of 2.3% (n = 100), for the oxidation of a high concentration (5 mM) of chlorophenol. In contrast, glassy carbon exhibited a response variability of 39.1%. After 100 injections, the relative peak intensity, for diamond decreased by 10%, while a drastic decrease of 70% was observed for glassy carbon. The detection limit obtained in the FIA mode for 2,4-dichlorophenol was found to be 20 nM (S/N = 3), with a linear dynamic range up to 100 microM. By coupling with the column-switching technique, which enabled on-line preconcentration (50 times), the detection limit was lowered to 0.4 nM (S/N = 3). By use of this technique, anodized diamond electrodes were demonstrated for the analysis of CPs in drainwater that was condensed from the flue gas of waste incinerators. 相似文献