全文获取类型
收费全文 | 159篇 |
免费 | 0篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 1篇 |
废物处理 | 23篇 |
环保管理 | 5篇 |
综合类 | 11篇 |
基础理论 | 28篇 |
污染及防治 | 46篇 |
评价与监测 | 30篇 |
社会与环境 | 19篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 5篇 |
2022年 | 20篇 |
2021年 | 18篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 12篇 |
2017年 | 10篇 |
2016年 | 11篇 |
2015年 | 5篇 |
2014年 | 9篇 |
2013年 | 9篇 |
2012年 | 11篇 |
2011年 | 7篇 |
2010年 | 8篇 |
2009年 | 2篇 |
2008年 | 11篇 |
2007年 | 8篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 2篇 |
1999年 | 1篇 |
1995年 | 1篇 |
排序方式: 共有164条查询结果,搜索用时 53 毫秒
81.
Uses and misuses of bioclimatic envelope modeling 总被引:5,自引:0,他引:5
Bioclimatic envelope models use associations between aspects of climate and species' occurrences to estimate the conditions that are suitable to maintain viable populations. Once bioclimatic envelopes are characterized, they can be applied to a variety of questions in ecology, evolution, and conservation. However, some have questioned the usefulness of these models, because they may be based on implausible assumptions or may be contradicted by empirical evidence. We review these areas of contention, and suggest that criticism has often been misplaced, resulting from confusion between what the models actually deliver and what users wish that they would express. Although improvements in data and methods will have some effect, the usefulness of these models is contingent on their appropriate use, and they will improve mainly via better awareness of their conceptual basis, strengths, and limitations. 相似文献
82.
Hoelscher Fernanda Cardoso Priscilla B. Candiotto Graziâni Guindani Camila Feuser Paulo Araújo Pedro H. H. Sayer Claudia 《Journal of Polymers and the Environment》2021,29(11):3668-3678
Journal of Polymers and the Environment - Biodegradability is a key feature for the application of polymeric devices in medicine. This study reports an experimental and theoretical study of the... 相似文献
83.
Highly concentrated phenolic wastewater treatment by the photo-Fenton reaction, mechanism study by FTIR-ATR 总被引:3,自引:0,他引:3
Araña J Tello Rendón E Doña Rodríguez JM Herrera Melián JA González Díaz O Pérez Peña J 《Chemosphere》2001,44(5):1017-1023
Phenol degradation by Photo-Fenton reaction has been studied in highly concentrated wastewaters and most intermediate species have been identified by Fourier Transform IR-Spectroscopy with ATR device. During the photodegradation of highly concentrated phenol solutions, the formation of dissolved and precipitate tannin has been observed. The possibility of a Fe3+-Pyrogallol complex formation, previous to the tannin formation, has been proposed too. The complex formation involving Fe3+ ions could be related to the observed Photo-Fenton activity decrease. Tannin formation inhibits the complete mineralization of phenol because *OH radicals attack will produce further condensation steps and the polymer size increase. This fact limits the applicability of the process for highly concentrated phenolic wastes mineralization. However, the tannin precipitation allows its separation from the solution by conventional filtration, and reduction of the corresponding dissolved organic carbon. These observations have been proved from the identification of primary degradation products, catechol and hydroquinone. Catechol is considered to be the first step for the formation of tannins. Degradation process for phenol, catechol and hydroquinone have been monitored by total organic carbon (TOC) measurements along the reaction time span. From these results, a global mechanism for the Photo-Fenton degradation of phenol is proposed. 相似文献
84.
The application of micro-electrical discharge machining (micro-EDM) in deep-hole drilling is still limited due to the difficulty in flushing of debris and unstable machining. Present study introduces a simplistic analytical model to evaluate the effectiveness of low frequency workpiece vibration during the micro-EDM drilling of deep micro-holes. In addition, experimental investigation has been conducted to validate the model by studying the effects of workpiece vibration on machining performance, surface quality and dimensional accuracy of the micro-holes. The effect of vibration frequency and amplitude for three different settings of aspect ratios has been studied experimentally. Moreover, the vibration experiments have been conducted at different levels of gap voltages and capacitances in order to understand the effect of electrical parameters and effectiveness of low-frequency workpiece-vibration at different levels of discharge energies. It has been shown analytically that the effectiveness of low frequency workpiece vibration during micro-EDM drilling can be evaluated by a parameter ‘Kv’ (ratio of maximum acceleration of the vibrating plate in gravitational direction to gravitational acceleration ‘g’), which can be determined from the vibration frequency, amplitude and phase angle of the vibrating workpiece. The theoretical model reveals that for Kv > 1, the position of debris particles will be above the workpiece; thus can be flushed away from machined zone effectively. The experimental reasons for improved micro-EDM drilling performance at the setting of Kv > 1 are found to be the increased effective discharge ratio, reduced short-circuits and improved dielectric flushing. The experimental results also reveal that the low frequency vibration is more effective at the low discharge energy level, thus making it more suitable for micro-EDM. Considering the effect on both the machining characteristics and micro-hole accuracy parameters, vibration frequency of 750 Hz and amplitude of 1.5 μm was found to provide improved performance for the developed vibration device. 相似文献
85.
86.
Alessandro C de Araújo Bart Kruijt Antonio D Nobre Albertus J Dolman Maarten J Waterloo Eddy J Moors Juliana S de Souza 《Ecological applications》2008,18(6):1406-1419
Flux measurements of carbon dioxide and water vapor above tropical rain forests are often difficult to interpret because the terrain is usually complex. This complexity induces heterogeneity in the surface but also affects lateral movement of carbon dioxide (CO2) not readily detected by the eddy covariance systems. This study describes such variability using measurements of CO2 along vertical profiles and along a toposequence in a tropical rain forest near Manaus, Brazil. Seasonal and diurnal variation was recorded, with atmospheric CO2 concentration maxima around dawn, generally higher CO2 build-up in the dry season and stronger daytime CO2 drawdown in the wet season. This variation was reflected all along the toposequence, but the slope and valley bottom accumulated clearly more CO2 than the plateaus, depending on atmospheric stability. Particularly during stable nights, accumulation was along lines of equal altitude, suggesting that large amounts of CO2 are stored in the valleys of the landscape. Flushing of this store only occurs during mid-morning, when stored CO2 may well be partly transported back to the plateaus. It is clear that, for proper interpretation of tower fluxes in such complex and actively respiring terrain, the horizontal variability of storage needs to be taken into account not only during the night but also during the mornings. 相似文献
87.
Pal Sudip Kumar Masum Md. Mehedi Hassan Salauddin Md. Hossen Md. Arif Ruva Israt Jahan Akhie Afsana Alam 《Environmental science and pollution research international》2023,30(13):36112-36126
Environmental Science and Pollution Research - Urban stormwater runoff is considered as one of the major contributors to nonpoint source that contributes to the pollution of all water resources in... 相似文献
88.
Gomes Marinna Lopes F. Prado Dayanne de Oliveira Correia Tamires Partélli Lyra Gustavo Bastos de Araújo Emanuel José Gomes Graham James Jim 《Environment, Development and Sustainability》2021,23(10):14436-14452
Environment, Development and Sustainability - In state of Rio de Janeiro, the Southeast Region of Brazil, 97.91% of the reforested areas contain exclusively species of Pinus and Eucalyptus. Due to... 相似文献
89.
Metal mixtures in pregnant women and umbilical cord blood at urban populations—Rio de Janeiro,Brazil
de Figueiredo Nataly Damasceno Araújo Monica Seefelder Luiz Ronir R de Magalhaes Câmara Volney do Couto Jacob Silvana dos Santos Lisia Maria Gobbo Vicentini Santos Alves Asmus Carmen Ildes Rodrigues Froes 《Environmental science and pollution research international》2020,27(32):40210-40218
Environmental Science and Pollution Research - This study aims to assess interrelationships between serum lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg) concentrations in pregnant women in... 相似文献
90.
Priscilla Araújo Victor Sílvia Belém Gonçalves Fabricio Machado 《Journal of Polymers and the Environment》2018,26(5):1755-1774
A modified sequential mass-suspension polymerization was employed to ensure adequate dispersion of lignin into the monomeric phase. Due to its complex macromolecular structure and low compatibility with styrene, eucalyptus wood-extracted lignin, via a modified Kraft method, was esterified with methacrylic anhydride to ensure organic phase homogeneity into the reaction medium. Infrared spectroscopy showed a decrease in the hydroxyl band, a characteristic of natural lignin (3200–3400 cm?1) and an increase in the characteristic ester band (1720–1740 cm?1) whereas nuclear magnetic resonance measurements exhibited intense peaks in the range from 1.7 to 2.05 ppm (–CH3) and 5.4 to 6.2 ppm (=CH2), related to methacrylic anhydride. Comparatively, the esterified lignin also displayed an increase of its glass transition temperature for 98?°C, related to natural lignin, whose T g was determined to be equal to 91?°C. Styrene/lignin-based polymers exhibited higher average molar masses in comparison to the values observed for polystyrene synthesized with similar amounts of benzoyl peroxide, due to the ability of lignin to act as a free-radical scavenger. Composites obtained with styrene and natural or esterified lignin were successfully synthesized, presenting regular morphology and proper lignin dispersion. Based on a very simple polymerization system, it is possible to enhance the final properties of polystyrene through the incorporation of lignin, which represents an important platform for developing attractive polymeric materials from renewable resources. 相似文献