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31.
Journal of Polymers and the Environment - The aim of this study is to investigate the effect of fiber length and loading on physico-mechanical and flammability properties of Cyrtostachys renda (CR)...  相似文献   
32.
Environmental Science and Pollution Research - Epilepsy is one of the most common serious brain disorders, affecting about 1% of the population all over the world. Ginkgo biloba extract (GbE) and...  相似文献   
33.
Island biogeography theory and nestedness are two relevant and important concepts in biogeography and conservation. However, their integration and application has not been examined for maintaining or maximizing species diversity, especially in arid regions. The aim of this study is to investigate the ecological mechanisms related to the observed pattern of floristic diversity and nestedness in the Lake Bardawil islets on the Mediterranean coast of Sinai Peninsula before the execution of the North Sinai Agricultural Development Project (NSADP) that will threaten the ecosystem of the lake. Plant species on 15 islets were identified and categorized into ecological groups related to their life-form, salt tolerance and succulence. Richness of total plant species and their ecological groups were positively correlated with islet area, number of habitats and elevation, and negatively with disturbance index. The temperature calculator detected highly significant nestedness for the entire flora and all ecological groups. Distance from the mainland had no effect on either species richness or nested pattern of total plant species and their ecological groups. Both the analyses of species richness and nested distribution yielded evidence for a positive species-area relationship. Although nestedness was detected for the entire plant species and their ecological groups, many species and islets exhibited idiosyncratic distribution. Idiosyncrasies could be mainly attributed to demographic stochasticity which is an important character for species interaction and diversity maintenance in arid regions. Therefore, in developing conservation strategies for the Lake Bardawil islets, it is important to incorporate spatial and temporal stability of populations.  相似文献   
34.
In this paper, we investigated: (1) the predictability of different aspects of biodiversity, (2) the effect of spatial autocorrelation on the predictability and (3) the environmental variables affecting the biodiversity of free-living marine nematodes on the Belgian Continental Shelf. An extensive historical database of free-living marine nematodes was employed to model different aspects of biodiversity: species richness, evenness, and taxonomic diversity. Artificial neural networks (ANNs), often considered as “black boxes”, were applied as a modeling tool. Three methods were used to reveal these “black boxes” and to identify the contributions of each environmental variable to the diversity indices. Since spatial autocorrelation is known to introduce bias in spatial analyses, Moran's I was used to test the spatial dependency of the diversity indices and the residuals of the model. The best predictions were made for evenness. Although species richness was quite accurately predicted as well, the residuals indicated a lack of performance of the model. Pure taxonomic diversity shows high spatial variability and is difficult to model. The biodiversity indices show a strong spatial dependency, opposed to the residuals of the models, indicating that the environmental variables explain the spatial variability of the diversity indices adequately. The most important environmental variables structuring evenness are clay and sand fraction, and the minimum annual total suspended matter. Species richness is also affected by the intensity of sand extraction and the amount of gravel of the sea bed.  相似文献   
35.
Citrus Sudden Death (CSD) is a disease that has affected sweet orange trees grafted on Rangpur lime in the south of Minas Gerais state and in the north of São Paulo state (Brazil). This is a worrying characteristic because the Rangpur lime responds to 85% of the Brazilian citrus rootstocks. This disease is believed to be caused by a virus transmitted by aphids (vector) of the citrus. In this work, we have adopted the Cellular Automata model (CA) to study the temporal evolution of the disease. We take into account the effect of the wind in the space covered by the aphid. To establish the relationship between the space covered by the aphid and the intensity of the wind, we have adopted the rule-based fuzzy system. Simulations were performed and compared to real data. Through the use of the mean absolute error (MAE) method, it was possible to verify a 70% of similarity between our model of data and the real one.  相似文献   
36.

Climate change issues are calling for advanced methods to produce materials and fuels in a carbon–neutral and circular way. For instance, biomass pyrolysis has been intensely investigated during the last years. Here we review the pyrolysis of algal and lignocellulosic biomass with focus on pyrolysis products and mechanisms, oil upgrading, combining pyrolysis and anaerobic digestion, economy, and life cycle assessment. Products include oil, gas, and biochar. Upgrading techniques comprise hot vapor filtration, solvent addition, emulsification, esterification and transesterification, hydrotreatment, steam reforming, and the use of supercritical fluids. We examined the economic viability in terms of profitability, internal rate of return, return on investment, carbon removal service, product pricing, and net present value. We also reviewed 20 recent studies of life cycle assessment. We found that the pyrolysis method highly influenced product yield, ranging from 9.07 to 40.59% for oil, from 10.1 to 41.25% for biochar, and from 11.93 to 28.16% for syngas. Feedstock type, pyrolytic temperature, heating rate, and reaction retention time were the main factors controlling the distribution of pyrolysis products. Pyrolysis mechanisms include bond breaking, cracking, polymerization and re-polymerization, and fragmentation. Biochar from residual forestry could sequester 2.74 tons of carbon dioxide equivalent per ton biochar when applied to the soil and has thus the potential to remove 0.2–2.75 gigatons of atmospheric carbon dioxide annually. The generation of biochar and bio-oil from the pyrolysis process is estimated to be economically feasible.

  相似文献   
37.
Environmental Science and Pollution Research - Silver nanoparticles (AgNPs) are noble metal nanoparticles, due to their good physicochemical properties, which have been exploited in biological...  相似文献   
38.
Objectives: This study set out to examine seat belt and child restraint use in the Dammam Municipality of the Kingdom of Saudi Arabia, based on the premise that an increase in seat belt use would significantly reduce personal injury in traffic crashes. It was expected that local data would help identify intervention strategies necessary to improve seat belt use in the region.

Methods: The research involved 2 methodologies. First, 1,389 face-to-face interviews were conducted with male and female adults in regional shopping plazas regarding their own and their children's restraint use in their vehicles and reasons for these attitudes and beliefs. Second, 2 on-road observation studies of adult and child restraint use were conducted by trained observers. Occupants of approximately 5,000 passenger vehicles were observed while stopped at representative signalized traffic intersections.

Results: The findings showed front seat belt use rates of between 43 and 47% for drivers and 26 to 30% for front seat passengers; rear seat belt use rates were lower. While there seemed to be some knowledge about the purpose and reasons for restraining both adults and children in suitable restraints, this failed to be confirmed in the on-road observations.

Conclusions: Reasons for these rates and findings are discussed fully, and recommendations for improving seat belt use in the Dammam Municipality are included.  相似文献   

39.
The lakes’ fisheries play an important role in Egyptian economy. In 1980s, they provided more than 50 % of harvested fish in Egypt but now their contribution to the Egypt fish production decreased to only 12.5 % in 2012. Lake Timsah, one of the Suez Canal lakes, faced many challenges that lead to serious changes in its water and fish quality, fish production, as well as the catch composition. The present work investigated the impact of pollution, food availability, and excessive fishing mortality on the haffara production in lake Timsah. The distribution of four heavy metals (Pb, Zn, Ni, and Fe) was detected seasonally in water and in muscles, gills, and livers of Rhabdosargus haffara, during 2012 through 2013. Fe and Zn were presented by high values in liver, while Pb and Ni in gills. Generally, the lowest concentrations of all metals were found in muscles. The recorded crustacean organisms (the main food of haffara) decreased from 12 species and 32,079 organisms?m2 in 2012 to only 7 species and 7290 organisms?m2 in 2013 while the amphipods completely disappeared. This serious change was due to the severe pollution in the lake. A logistic surplus production model was fitted to the catch per unit effort indices, to estimate the maximum sustainable yield and the optimum level of fishing effort. The results revealed that haffara stock at lake Timsah is overfished, and the estimated precautionary target reference points advised the reduction of fishing effort by about 30–50 %.  相似文献   
40.
Copolymers of aniline and o-phenylenediamine/kaolinite composites were synthesized by 5:1 molar ratios of the respective monomers with different percentages of nanoclay via modified in situ chemical co-polymerization. The results were verified by measuring the FT-IR and UV–vis absorption spectra for PANI-o-PDA/kaolinite composites. The thermal behaviour of the copolymer and composites was studied. PANI-o-PDA/kaolinite composites were thermally more stable than pure copolymer. Surface morphology of copolymer composites was recorded at different magnification power by SEM which revealed whitish micrometric beads distributed all over the field with particle size in the range of 0.122–0.233 μm. This work demonstrates that the PANI-o-PDA/kaolinite composites particles can be considered as potential adsorbents for hazardous and toxic metal ions of water from lake El-Manzala, Egypt. All of Cd(II), Cu(II), and Pb(II) posed dangerous health risk to the local population via fish consumption.  相似文献   
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