全文获取类型
收费全文 | 164篇 |
免费 | 17篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 6篇 |
化学工业 | 46篇 |
机械仪表 | 4篇 |
建筑科学 | 3篇 |
能源动力 | 5篇 |
轻工业 | 39篇 |
水利工程 | 2篇 |
石油天然气 | 3篇 |
无线电 | 17篇 |
一般工业技术 | 25篇 |
冶金工业 | 5篇 |
自动化技术 | 27篇 |
出版年
2022年 | 10篇 |
2021年 | 10篇 |
2020年 | 7篇 |
2019年 | 11篇 |
2018年 | 14篇 |
2017年 | 22篇 |
2016年 | 13篇 |
2015年 | 8篇 |
2014年 | 7篇 |
2013年 | 17篇 |
2012年 | 15篇 |
2011年 | 10篇 |
2010年 | 12篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 3篇 |
2005年 | 3篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1988年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有182条查询结果,搜索用时 15 毫秒
1.
Purification,structural data and biological properties of polysaccharide from Prunus amygdalus gum 下载免费PDF全文
Fatma Bouaziz Mohamed Koubaa Claire Boisset Helbert Fatma Kallel Dorra Driss Imen Kacem Raoudha Ghorbel Semia Ellouz Chaabouni 《International Journal of Food Science & Technology》2015,50(3):578-584
This work demonstrates the efficiency of almond gum polysaccharides (AGPs) as bioactive compounds. AGPs were first extracted using H2O2, in the presence of NaOH, at different times and temperatures. The optimal extraction conditions were 4% H2O2 and 2 N NaOH, for 7 h at 50 °C, leading to an extraction yield of 58.2% (w/w). After a purification step, the retained AGPs were characterised using high‐performance liquid chromatography showing a molecular weight of 99.3 kDa. The monosaccharide composition of AGPs were assessed using gas chromatography–mass spectrometry. AGPs were found to be a complex heteropolysaccharide with a repeating unit mainly composed of galactose, arabinose, xylose, mannose, rhamnose, and glucuronic acid with the respective ratios: 45:26:7:10:1:11. The acidic nature of the polysaccharide is due to the presence of glucuronic acid. Total antioxidant activity, free radical‐scavenging activity and reducing power assay of AGPs were investigated. The obtained results showed high antioxidant activities of AGPs. Furthermore, beyond 60 mg mL?1, AGPs exhibited bacterial growth inhibition for five pathogenic strains: Escherichia coli, Staphylococcus aureus, Enterococcus feacalis, Pseudomonas aeruginosa and Salmonella typhimurium. 相似文献
2.
3.
4.
Impact of the Cd2+ treatment on the electrical properties of Cu2ZnSnSe4 and Cu(In,Ga)Se2 solar cells
Khaled Ben Messaoud Marie Buffire Guy Brammertz Hossam ElAnzeery Souhaib Oueslati Jonathan Hamon Bas J. Kniknie Marc Meuris Mosbah Amlouk Jef Poortmans 《Progress in Photovoltaics: Research and Applications》2015,23(11):1608-1620
The present contribution aims at determining the impact of modifying the properties of the absorber/buffer layer interface on the electrical performance of Cu2ZnSnSe4 (CZTSe) thin‐film solar cells, by using a Cd2+ partial electrolyte (Cd PE) treatment of the absorber before the buffer layer deposition. In this work, CZTSe/CdS solar cells with and without Cd PE treatment were compared with their respective Cu(In,Ga)Se2 (CIGSe)/CdS references. The Cd PE treatment was performed in a chemical bath for 7 min at 70 °C using a basic solution of cadmium acetate. X‐ray photoemission spectroscopy measurements have revealed the presence of Cd at the absorber surface after the treatment. The solar cells were characterized using current density–voltage (J–V), external quantum efficiency, and drive‐level capacitance profiling measurements. For the CZTSe‐based devices, the fill factor increased from 57.7% to 64.0% when using the Cd PE treatment, leading to the improvement of the efficiency (η) from 8.3% to 9.0% for the best solar cells. Similar observations were made on the CIGSe solar cell reference. This effect comes from a considerable reduction of the series resistance (RS) of the dark and light J–V, as determined using the one‐diode model. The crossover effect between dark and light J–V curves is also significantly reduced by Cd PE treatment. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
5.
Nazrin S. N. Umar S. A. Halimah M. K. Marian M. M. Najwa Z. W. Jufa M. S. Syahirah M. T. Zuhasanah Z. Azlan M. N. Geidam I. G. Boukhris Imed Kebaili Imen 《Journal of Inorganic and Organometallic Polymers and Materials》2022,32(7):2513-2526
Journal of Inorganic and Organometallic Polymers and Materials - Copper oxide doped TeO2–B2O3 glass system with empirical formula;... 相似文献
6.
In recent years, droughts with increasing severity and frequency have been experienced around the world due to climate change
effects. Water planning and management during droughts needs to deal with water demand variability, uncertainties in streamflow
prediction, conflicts over water resources allocation, and the absence of necessary emergency schemes in drought situations.
Reservoirs could play an important role in drought mitigation; therefore, development of an algorithm for operation of reservoirs
in drought periods could help to mitigate the drought impacts by reducing the expected water shortages. For this purpose,
the probable drought’s characteristics and their variations in response to factors such as climate change should be incorporated.
This study aims at developing a contingency planning scheme for operation of reservoirs in drought periods using hedging rules
with the objective of decreasing the maximum water deficit. The case study for evaluation of the performance of the proposed
algorithm is the Sattarkhan reservoir in the Aharchay watershed, located in the northwestern part of Iran. The trend evaluations
of the hydro-climatic variables show that the climate change has already affected streamflow in the region and has increased
water scarcity and drought severity. To incorporate the climate change study in reservoir planning; streamflow should be simulated
under climate change impacts. For this purpose, the climatic variables including temperature and precipitation in the future
under climate change impacts are simulated using downscaled GCM (General Circulation Model) outputs to derive scenarios for
possible future drought events. Then a hydrological model is developed to simulate the river streamflow, based on the downscaled
data. The results show that the proposed methodology leads to less water deficit and decreases the drought damages in the
study area. 相似文献
7.
Salma Lasram Souheib Oueslati Ana Valero Sonia Marin Abdelwahed Ghorbel Vicente Sanchis 《Journal of food science》2010,75(2):M89-M97
ABSTRACT: This study investigated the effects of temperature (15 to 37 °C) and water activity (0.90 to 0.99) on the growth and production of ochratoxin A (OTA) by Aspergillus carbonarius cultured on synthetic nutrient medium (SNM) after 5 and 10 d of incubation. Total of 8 ochratoxigenic A. carbonarius, isolated from vineyards located in different regions of Tunisia, were used. Growth data were modeled by the flexible model of Baranyi and growth rates at each set of conditions were obtained. For both growth and OTA production, optimal water activity was 0.99; however, optimal temperature varied. The optimal temperature for growth was 30 °C. At 37 °C, the growth rate decreased significantly (P < 0.05). Maximum toxin production occurred at temperatures in the range of 15 to 25 °C with the optimum one depending on the isolate tested. Significant amounts of OTA were produced after only 5 d of incubation. Our results showed that A. carbonarius isolated from Tunisian grapes behave as those from European and Australian grapes, as reported in the literature, although some differences in trends for growth and OTA production were observed. 相似文献
8.
Faouzia M. Haddada Dhouha Krichène Hédia Manai Imen Oueslati Douja Daoud Mokhtar Zarrouk 《European Journal of Lipid Science and Technology》2008,110(10):905-913
The characterization of virgin olive oils from six Tunisian cultivars, namely Chétoui, Ain Jarboua, Jarboui, Regregui, Rekhami and Neb Jmel, grown in Nebeur (a region of the Kef) was carried out. These cultivars dominate their natural habitats, but with the exception of the Chétoui cultivar they are only scattered throughout the nation. Several analytical parameters were evaluated; these include quality index, fatty acid composition, chlorophylls, carotenoids, sterols, α‐tocopherol and phenolic compounds. Their relationship with oxidative stability was also tested. The main phenols found were tyrosol, hydroxytyrosol, the dialdehydic form of elenolic acid linked to tyrosol and hydroxytyrosol, oleuropein aglycon and pinoresinol. These phenolic compounds, the colorimetric total phenol content and o‐diphenols showed significant correlations with oxidative stability. Furthermore, most of the analytical parameters of the oils that were determined in this study were greatly influenced by genetic factors (cultivar). 相似文献
9.
Photodegradation of phenol red in the presence of oxyhydroxide of Fe(III) (Goethite) under artificial and a natural light 下载免费PDF全文
Sara Belattar Nadra Debbache Imen Ghoul Tahar Sehili Ala Abdessemed 《Water and Environment Journal》2018,32(3):358-365
The (α‐FeOOH) Goethite composite is a stable and an efficient catalyst in aqueous suspension under irradiation at 365 nm and by solar light. The photocatalytic activities of this composite were evaluated using Phenol Red (PR) dye (phenolsulfonphthalein class). In the dark, controlling factors, such as the pH and the adsorption of PR on Goethite surface were evaluated (before starting the photochemical experiments). It was found that the system PR‐Goethite present a small decrease in the main band of the dye (435 nm) which was explained by the low rate of adsorption of this dye on the Goethite. Also, we note that 40% of PR decolourisation was obtained after 200 min by the system PR‐Goethite‐hydrogen peroxide (H2O2) in dark due to the formation of ?OH by thermal decomposition of H2O2 on the surface of Goethite. The effects of various experimental parameters, such as initial dye concentration, pH, photocatalyst amount, tert‐Butyl alcohol effect and H2O2 addition were investigated in the study of photodegradation of the dye. The results showed that the photodegradation of PR under UV‐A (365 nm) irradiation could be enhanced greatly in the presence of H2O2. Natural radiation tests (under sunlight) showed that degradation was faster comparing with that obtained using the artificial one at 365 nm. Studies of the mineralization using total organic carbon method under naturel light certify that this method, compatible with the environment, may be considered in the treatment of wastewater and generally in the process of removal of this kind of pollutant. 相似文献
10.
Reliability and durability of proton exchange membrane fuel cells (PEMFCs) are one of the most complex issues in real applications' environment. Especially, when it subjects to the various mechanical loads and vibrations. This topic requires more attention for research and experimental works. In this study, the effect of mechanical loads was investigated on an open‐cathode PEMFC in operating state. Several long time vibration tests have been applied on non‐operating PEMFC, and the performance of the fuel cell was evaluated during the test. Hydrogen leakage as a key parameter was investigated in performance monitoring instead of measuring torque on compression bolts. The vibration tests were consisted of sine, shock and random for X, Y and Z axes in operating state and random vibration in non‐operating state of PEMFC. The experimental results in operating state were indicated that the fuel cell performance has not been affected by the proposed vibrations. Furthermore, the test results of non‐operating state have been shown that the performance of PEMFC reduces about 0.6% in each four‐hour step of the vibration test. In addition, the experiments reveal that if the mechanical loads and vibrations cause physical damage on the fuel cell components, they can change the performance and reliability of the fuel cell. 相似文献