全文获取类型
收费全文 | 289篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 7篇 |
废物处理 | 28篇 |
环保管理 | 19篇 |
综合类 | 26篇 |
基础理论 | 46篇 |
污染及防治 | 107篇 |
评价与监测 | 30篇 |
社会与环境 | 31篇 |
出版年
2023年 | 6篇 |
2022年 | 14篇 |
2021年 | 25篇 |
2020年 | 8篇 |
2019年 | 2篇 |
2018年 | 11篇 |
2017年 | 11篇 |
2016年 | 12篇 |
2015年 | 9篇 |
2014年 | 7篇 |
2013年 | 24篇 |
2012年 | 14篇 |
2011年 | 18篇 |
2010年 | 21篇 |
2009年 | 15篇 |
2008年 | 14篇 |
2007年 | 13篇 |
2006年 | 13篇 |
2005年 | 11篇 |
2004年 | 11篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1985年 | 2篇 |
1983年 | 2篇 |
排序方式: 共有294条查询结果,搜索用时 15 毫秒
61.
Adjusting for the operational environment in studies of performance measurement is very important, otherwise the analysis may lead to unrealistic scores, especially when its influence on costs is high, such as in the water utilities. In this paper, we study the influence of exogenous variables on the water utilities performance by applying conditional efficiency measures based on the order-m method and its probabilistic formulation. We use a sample of 66 water utilities operating between 2002 and 2008, representing about 70% of the Portuguese population. Our research suggests that inefficiency of Portuguese water utilities is substantial for some utilities: several exogenous variables might influence it considerably. For example, regulation has a positive influence on efficiency but when drinking water supply and wastewater services are provided by the same utility or when the wholesale and retail activities are provided together, the performance is lower. The effect of ownership is inconclusive and the variables residential customers, water source, peak factor, and density of customers have a mixed influence on performance which varies according to their scores. 相似文献
62.
Noguera D Laossi KR Lavelle P De Carvalho MH Asakawa N Botero C Barot S 《Ecological applications》2011,21(7):2349-2356
Tropical soils are particularly vulnerable to fertility losses due to their low capacity to retain organic matter and mineral nutrients. This urges the development of new agricultural practices to manage mineral nutrients and organic matter in a more sustainable way while relying less on fertilizer inputs. Two methods pertaining to ecological engineering and agroecology have been tested with some success: (1) the addition of biochar to the soil, and (2) the maintenance of higher earthworm densities. However, modern crop varieties have been selected to be adapted to agricultural practices and to the soil conditions they lead to and common cultivars might not be adapted to new practices. Using rice as a model plant, we compared the responsiveness to biochar and earthworms of five rice cultivars with contrasted selection histories. These cultivars had contrasted responsivenesses to earthworms, biochar, and the combination of both. The mean relative increase in grain biomass, among all treatments and cultivars, was 94% and 32%, respectively, with and without fertilization. Choosing the best combination of cultivar and treatment led to a more than fourfold increase in this mean benefit (a 437% and a 353% relative increase in grain biomass, respectively, with and without fertilization). Besides, the more rustic cultivar, a local landrace adapted to diverse and difficult conditions, responded the best to earthworms in terms of total biomass, while a modern common cultivar responded the best in term of grain biomass. This suggests that cultivars could be selected to amplify the benefit of biochar- and earthworm-based practices. Overall, selecting new cultivars interacting more closely with soil organisms and soil heterogeneity could increase agriculture sustainability, fostering the positive feedback loop between soils and plants that has evolved in natural ecosystems. 相似文献
63.
Silva Marcio Roberto Ferreira Fernando César Maranhão Adriana Gonçalves Lanzarini Natália Maria de Carvalho Castro Karina Neboo Miagostovich Marize Pereira 《Food and environmental virology》2021,13(4):528-534
Food and Environmental Virology - Enteric viruses have been described as important contaminants in fresh and ready-to-eat foods such as sandwiches, deli meat and dairy products. This is a... 相似文献
64.
Mavroulidou Maria Feruku Blendi Boulouki Georgia 《Journal of Material Cycles and Waste Management》2022,24(4):1317-1332
Journal of Material Cycles and Waste Management - This paper studies the use of wastepaper sludge ash (WPSA) for structural concrete in binary and ternary mixes with high-strength cement and two... 相似文献
65.
Cindy E. Hauser Katherine M. Giljohann Michael A. McCarthy Georgia E. Garrard Andrew P. Robinson Nicholas S. G. Williams Joslin L. Moore 《Conservation biology》2022,36(3):e13888
Surveys aimed at finding threatened and invasive species can be challenging due to individual rarity and low and variable individual detection rates. Detection rate in plant surveys typically varies due to differences among observers, among the individual plants being surveyed (targets), and across background environments. Interactions among these 3 components may occur but are rarely estimated due to limited replication and control during data collection. We conducted an experiment to investigate sources of variation in detection of 2 Pilosella species that are invasive and sparsely distributed in the Alpine National Park, Australia. These species are superficially similar in appearance to other yellow-flowered plants occurring in this landscape. We controlled the presence and color of flowers on target Pilosella plants and controlled their placement in plots, which were selected for their variation in cover of non-target yellow flowers and dominant vegetation type. Observers mimicked Pilosella surveys in the plots and reported 1 categorical and 4 quantitative indicators of their survey experience level. We applied survival analysis to detection data to model the influence of both controlled and uncontrolled variables on detection rate. Orange- and yellow-flowering Pilosella in grass- and heath-dominated vegetation were detected at a higher rate than nonflowering Pilosella. However, this detection gain diminished as the cover of other co-occurring yellow-flowering species increased. Recent experience with Pilosella surveys improved detection rate. Detection experiments are a direct and accessible means of understanding detection processes and interpreting survey data for threatened and invasive species. Our detection findings have been used for survey planning and can inform progress toward eradication. Interaction of target and background characteristics determined detection rate, which enhanced predictions in the Pilosella eradication program and demonstrated the difficulty of transferring detection findings into untested environments. 相似文献
66.
Olga S. Arvaniti Marilena E. Dasenaki Alexandros G. Asimakopoulos Niki C. Maragou Vasilios G. Samaras Korina Antoniou Georgia Gatidou Daniel Mamais Constantinos Noutsopoulos Zacharias Frontistis Nikolaos S. Thomaidis Athanasios S. Stasinakis 《Frontiers of Environmental Science & Engineering》2022,16(11):148
67.
Gomes Brener Felipe Melo Lima de Araújo Caroline Maria Bezerra do Nascimento Bruna Figueiredo Freire Eleonora Maria Pereira de Luna Da Motta Sobrinho Mauricio Alves Carvalho Marilda Nascimento 《Environmental science and pollution research international》2022,29(12):17358-17372
Environmental Science and Pollution Research - In this work, graphene oxide (GO) was synthesized by the modified Hummers method. The nanomaterial was characterized by FTIR and Raman spectroscopy,... 相似文献
68.
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
69.
Gonzalez-Fernandez O Hidalgo M Margui E Carvalho ML Queralt I 《Environmental pollution (Barking, Essex : 1987)》2008,153(2):476-482
Every year between 8 and 9 millions of vehicles in the European Union arrive to their end of life. Car wastes can have a very high metal content, falling into hazardous waste class. A preliminary evaluation of these wastes could be made by metals' leaching test runs which is the main objective of the present study. Evaluation of the total metal content was carried out by X-ray fluorescence and the mobility of these metals using two simple standardized extractions such as the TCLP (Toxicity Characterisation Leaching Procedure) of the US EPA and the German leaching test DIN 38414-S4. Additionally, an extraction test with acetone was performed in order to recognise metals bounded to organic matter. The results show that the total metal content of the ASR can overpass the established values for inert residues. Lead and zinc contents are fairly well correlated with grain-size, whilst other metals' contents do not exhibit clear grain-size dependence. 相似文献
70.
Alexander M. Kusmanoff Fiona Fidler Ascelin Gordon Georgia E. Garrard Sarah A. Bekessy 《Conservation biology》2020,34(5):1131-1141
Communication and advocacy approaches that influence attitudes and behaviors are key to addressing conservation problems, and the way an issue is framed can affect how people view, judge, and respond to an issue. Responses to conservation interventions can also be influenced by subtle wording changes in statements that may appeal to different values, activate social norms, influence a person's affect or mood, or trigger certain biases, each of which can differently influence the resulting engagement, attitudes, and behavior. We contend that by strategically considering how conservation communications are framed, they can be made more effective with little or no additional cost. Key framing considerations include, emphasizing things that matter to the audience, evoking helpful social norms, reducing psychological distance, leveraging useful biases, and, where practicable, testing messages. These lessons will help communicators think strategically about how to frame messages for greater effect. 相似文献