全文获取类型
收费全文 | 150篇 |
免费 | 10篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 54篇 |
机械仪表 | 6篇 |
建筑科学 | 4篇 |
能源动力 | 2篇 |
轻工业 | 24篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
无线电 | 13篇 |
一般工业技术 | 26篇 |
冶金工业 | 6篇 |
自动化技术 | 20篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 14篇 |
2018年 | 12篇 |
2017年 | 14篇 |
2016年 | 12篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 16篇 |
2012年 | 8篇 |
2011年 | 16篇 |
2010年 | 13篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 2篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有160条查询结果,搜索用时 15 毫秒
101.
M.R. Bayati F. Golestani-Fard A.Z. Moshfegh Roya Molaei 《Materials Research Bulletin》2011,46(10):1642-1647
Micro arc oxidation technique, as a facile and efficient process, was employed to grow sulfur doped titania porous layers. This research sheds light on the photocatalytic performance of the micro arc oxidized S-TiO2 nano-porous layers fabricated under pulse current. Morphological and topographical studies, performed by SEM and AFM techniques, revealed that increasing the frequency and/or decreasing the duty cycle resulted in formation of finer pores and smoother surfaces. XRD and XPS results showed that the layers consisted of anatase and rutile phases whose fraction was observed to change depending on the synthesis conditions. The highest anatase relative content was obtained at the frequency of 500 Hz and the duty cycle of 5%. Furthermore, photocatalytic activity of the layers was examined by measuring the decomposition rate of methylene blue under both ultraviolet and visible photo irradiations. Maximum photodegradation reaction rate constants over the pulse-grown S-TiO2 layers were respectively measured as 0.0202 and 0.0110 min−1 for ultraviolet and visible irradiations. 相似文献
102.
Impact of fuel quality regulation and speed reductions on shipping emissions: implications for climate and air quality 总被引:1,自引:0,他引:1
Lack DA Cappa CD Langridge J Bahreini R Buffaloe G Brock C Cerully K Coffman D Hayden K Holloway J Lerner B Massoli P Li SM McLaren R Middlebrook AM Moore R Nenes A Nuaaman I Onasch TB Peischl J Perring A Quinn PK Ryerson T Schwartz JP Spackman R Wofsy SC Worsnop D Xiang B Williams E 《Environmental science & technology》2011,45(20):9052-9060
Atmospheric emissions of gas and particulate matter from a large ocean-going container vessel were sampled as it slowed and switched from high-sulfur to low-sulfur fuel as it transited into regulated coastal waters of California. Reduction in emission factors (EFs) of sulfur dioxide (SO?), particulate matter, particulate sulfate and cloud condensation nuclei were substantial (≥ 90%). EFs for particulate organic matter decreased by 70%. Black carbon (BC) EFs were reduced by 41%. When the measured emission reductions, brought about by compliance with the California fuel quality regulation and participation in the vessel speed reduction (VSR) program, are placed in a broader context, warming from reductions in the indirect effect of SO? would dominate any radiative changes due to the emissions changes. Within regulated waters absolute emission reductions exceed 88% for almost all measured gas and particle phase species. The analysis presented provides direct estimations of the emissions reductions that can be realized by California fuel quality regulation and VSR program, in addition to providing new information relevant to potential health and climate impact of reduced fuel sulfur content, fuel quality and vessel speed reductions. 相似文献
103.
Mohammad Hossein Rouhani Roya Kelishadi Mahin Hashemipour Ahmad Esmaillzadeh Leila Azadbakht 《Lipids》2013,48(12):1197-1205
Some studies focused on the effect of the dietary glycemic index on lipoproteins and apolipoproteins in adults; however, little evidence exists among adolescents regarding the effect of a low glycemic index (LGI) diet on apolipoproteins and lipoprotein (a) (Lpa). This study was conducted to evaluate the effect of an LGI diet on the lipid profile, apolipoproteins and Lpa among overweight and obese adolescent girls. For this parallel designed randomized clinical trial, 50 healthy overweight/obese girls at pubertal ages were randomly allocated to an LGI or a healthy nutritional recommendations (HNR) based diet. Equal macronutrient distributed diets were prescribed to both groups. Biochemical measurements included lipid profile, apolipoprotein A, apolipoprotein B and Lpa were conducted before and after 10 weeks of intervention. Forty one adolescent girls completed the study. The dietary glycemic index in the LGI group was 42.67 ± 0.067. There were no differences in the mean of blood lipid indices baseline and after intervention between two groups. There were no significant differences between the two groups regarding lipid profiles, apolipoproteins and Lpa. There were no significant differences in lipid profiles, apolipoproteins and Lpa between the LGI diet and the HNR-based diet and the impact of these two diets on lipid profile was equal in this trial. Trial registry code: IRCT201109272839N4. 相似文献
104.
Ganesh Kumar Agrawal Abhijit Sarkar Pier Giorgio Righetti Romina Pedreschi Sebastien Carpentier Tai Wang Bronwyn J. Barkla Ajay Kohli Bongani Kaiser Ndimba Natalia V. Bykova Christof Rampitsch Lello Zolla Mohamed Suhail Rafudeen Rainer Cramer Laurence Veronique Bindschedler Nikolaos Tsakirpaloglou Roya Janeen Ndimba Jill M. Farrant Jenny Renaut Dominique Job Shoshi Kikuchi Randeep Rakwal 《Mass spectrometry reviews》2013,32(5):335-365
105.
Roya Khalil Andrew George Chryss Margaret Jollands Satinath Bhattacharya 《Journal of Materials Science》2007,42(24):10219-10227
This paper focuses on the application of silica rich, rice hull ash (RHA) from the rice industry as filler in polypropylene
(PP). The dynamic rheological behaviour and the crystallinity of its composites with semi-amorphous polypropylene were used
as performance indicators. The effect of coupling agents on RHA/PP compatibility was also investigated. Addition of RHA increased
storage modulus (G′), and the onset (T
co) and peak (T
c) crystallinity temperatures, and decreased the degree of crystallinity of the system. Two coupling agents, maleated polypropylene
(MAPP) and an amino functional silane, were used to improve the interfacial adhesion of RHA and PP. Addition of MAPP increased
G′, T
c and T
co and the crystalline phase of the system. Addition of silane had mixed effects. It increased the rheological properties at
higher concentrations, it increased T
c and T
co at all the concentrations and increased crystallinity at lower concentrations and decreased it at higher concentrations.
Results from a thermogravimetric analyser were useful in revealing the mechanism by which silane bond to RHA and its effect
on the rheology and crystallisation behaviour of the composites. 相似文献
106.
A biomimetic route for synthesis of a conducting molecular complex between polyalkoxyanilines and a polyelectrolyte, poly (sodium 4‐styrenesulfonate) (SPS) is presented. Horseradish peroxidase (HRP) was used to catalyze the polymerization of alkoxyanilines. A few of water‐soluble ring‐substituted polyalkoxyanilines have been enzymatically synthesized with variation of groups, such as ortho‐methoxy, meta‐methoxy, ortho‐ethoxy, and meta‐ethoxy to form polyalkoxyanilines/SPS complexes. The presence of alkoxy substituents affects the polymerization reactions. These enzymatic oxidation reactions occur in a different potential range to that observed for the chemical polymerization. Similar electrochemical and optical properties were obtained for every pair of ortho‐ and meta‐alkoxy substituted polyanilines. For comparing, polyalkoxyanilines were also prepared by chemical polymerization in the presence of SPS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 103: 3724–3729, 2007 相似文献
107.
Our study investigated the impact of ICT expansion on economic freedom in the Middle East (Bahrain, Iran, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, Syria, United Arab Emirates, and Yemen). Our empirical analysis used archival data from 1995 to 2005; it showed that ICT expansion in the Middle East has been effective both in bridging the digital divide and also in promoting economic freedom in a region that was vulnerable to political, social, and global conflict. However, differences between countries, such as the educational attainment of their citizens and institutional resistance to technology acceptance, both enhanced and restricted the relationship between ICT and economic freedom. 相似文献
108.
Roya Dehghan Thomas W. Hansen Jakob B. Wagner Anders Holmen Erling Rytter Øyvind Borg John C. Walmsley 《Catalysis Letters》2011,141(6):754-761
Abstract
Reduction of 12wt.%Co/0.5wt.%Re/α-Al2O3 Fischer–Tropsch catalyst has been studied in-situ in an environmental transmission electron microscope. Reduction of Co3O4 to metallic cobalt was observed dynamically at 360 °C under 3.4 mbar H2. Structural and morphological changes were observed by high resolution transmission electron microscopy and scanning transmission electron microscopy imaging. The cobalt particles were mainly face centred cubic while some hexagonal close packed particles were also found. Reoxidation of the sample upon cooling to room temperature, still under flowing H2, underlines the reactivity of the nanoparticles and the importance of controlling the gas composition and specimen temperature during this type of experiment. Similar behaviour was observed for a non-promoted catalyst. Imaging and analysis of the promoted sample before and after reduction indicated a uniform distribution of the promoter. 相似文献109.
Electrochemical oxidation of 4-morpholinoaniline has been studied in various pHs using cyclic voltammetry and controlled-potential coulometry. The electrochemical trimerization of 4-morpholinoaniline is described and its mechanism has been studied in aqueous solution. This method provides a green, reagent-less, and environmentally friendly procedure with high atom economy, for the synthesis of “4-morpholinoaniline-trimer” using a carbon electrode in an undivided cell in good yield and purity. 相似文献