收费全文 | 831篇 |
免费 | 11篇 |
国内免费 | 25篇 |
安全科学 | 41篇 |
废物处理 | 88篇 |
环保管理 | 77篇 |
综合类 | 55篇 |
基础理论 | 149篇 |
环境理论 | 1篇 |
污染及防治 | 279篇 |
评价与监测 | 129篇 |
社会与环境 | 43篇 |
灾害及防治 | 5篇 |
2023年 | 18篇 |
2022年 | 102篇 |
2021年 | 76篇 |
2020年 | 21篇 |
2019年 | 36篇 |
2018年 | 40篇 |
2017年 | 51篇 |
2016年 | 58篇 |
2015年 | 35篇 |
2014年 | 48篇 |
2013年 | 108篇 |
2012年 | 44篇 |
2011年 | 54篇 |
2010年 | 27篇 |
2009年 | 35篇 |
2008年 | 22篇 |
2007年 | 18篇 |
2006年 | 11篇 |
2005年 | 8篇 |
2004年 | 9篇 |
2003年 | 5篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1969年 | 1篇 |
In this study, the wheat gluten film was prepared. Heracleum persicum essence, magnesium oxide nanoparticles and polypyrrole were used to modify the structure of the wheat gluten film. Physicochemical properties of the prepared films such as thickness, solubility, moisture absorption ability, antioxidant properties, and electrical conductivity of the films were investigated. Also, the mechanical, structural and thermal properties of the films were investigated by techniques such as SEM, FTIR, XRD, TGA, DTA and tissue analysis. SEM images showed that the essence and polypyrrole strengthened the gluten film structure and made it more resistant to the passage of gases. FTIR spectra confirmed the electrostatic interactions between gluten and essence and polypyrrole. XRD spectra showed the amorphous structure of gluten film and its composites. The results of thermal analysis showed that polypyrrole greatly increased the thermal resistance of the film and the nanoparticles had little effect on the thermal resistance. Thickness, solubility, moisture content and ability to absorb moisture were further affected by the essential oil. The antioxidant and electrical conductivity of the film was greatly increased in the presence of all three additives of essence, magnesium oxide nanoparticles and polypyrrole. The gluten–essence–MgO–PPy (Glu–E–MgO–PPy) composite film had the most antioxidant properties. Glu–E–MgO–PPy film with important electrical conductivity and antioxidant properties has the potential to be used as an active and intelligent film in the packaging of perishable food products.
相似文献The present study investigates the feasibility of using two types of municipality solid wastes incineration ashes, namely, fly ash and bottom ash in the production of sustainable alkali-activated binder. The ashes are collected from the incineration plant and characterized to determine their particle size distribution, specific gravity, chemical composition, and heavy metals content. The ashes are then used as either fly ash or sand replacement with five replacement ratios 0%, 5%, 10%, 15%, and 20% to produce the binder. The produced binder are characterized in terms of strength, workability, density, water absorption, thermal conductivity and stability, chemical composition, and heavy metals content. The results reflect the ability of producing sustainable alkali-activated binder with small dosage of MSWI ashes as either fly ash or sand replacement without negatively affecting its strength, workability, density, and water absorption. The ashes enhance the thermal insulation capability of the binder.
相似文献