收费全文 | 907篇 |
免费 | 11篇 |
国内免费 | 31篇 |
安全科学 | 36篇 |
废物处理 | 91篇 |
环保管理 | 83篇 |
综合类 | 75篇 |
基础理论 | 152篇 |
环境理论 | 2篇 |
污染及防治 | 301篇 |
评价与监测 | 139篇 |
社会与环境 | 54篇 |
灾害及防治 | 16篇 |
2023年 | 16篇 |
2022年 | 108篇 |
2021年 | 85篇 |
2020年 | 24篇 |
2019年 | 38篇 |
2018年 | 47篇 |
2017年 | 50篇 |
2016年 | 52篇 |
2015年 | 37篇 |
2014年 | 47篇 |
2013年 | 115篇 |
2012年 | 46篇 |
2011年 | 69篇 |
2010年 | 36篇 |
2009年 | 42篇 |
2008年 | 22篇 |
2007年 | 23篇 |
2006年 | 12篇 |
2005年 | 10篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 5篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1959年 | 1篇 |
1958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Introduction
This study was hypothesized that salicylic acid elevates the level of antioxidant system that will protect plants from the stress generated by nickel and/or salinity. 相似文献The free radicals produced by cigarette smoking are responsible for tissue damage, heart and lung diseases, and carcinogenesis. The effect of tobacco on the central nervous system (CNS) has received increased attention nowadays in research. Therefore, to explore the molecular interaction of cigarette smoke carcinogens (CSC) 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanol (NNAL), 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanone (NNK), and N′-nitrosonornicotine (NNN) with well-known targets of CNS-related disorders, acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) enzymes, a cascade of the computational study was conducted including molecular docking and molecular dynamics simulations (MDS). The investigated results of NNAL+AChEcomplex, NNK+AChEcomplex, and NNK+BuChEcomplex based on intermolecular energies (?G) were found to ?8.57 kcal/mol, ?8.21 kcal/mol, and ?8.08 kcal/mol, respectively. MDS deviation and fluctuation plots of the NNAL and NNK interaction with AChE and BuChE have shown significant results. Further, Molecular Mechanics Poisson-Boltzmann Surface Area (MM‐PBSA) results shown the best total binding energy (Binding?G) ?87.381 (+/?13.119) kJ/mol during NNK interaction with AChE. Our study suggests that CSC is well capable of altering the normal biomolecular mechanism of CNS; thus, obtained data could be useful to design extensive wet laboratory experimentation to know the effects of CSC on human CNS.
Graphical abstract 相似文献