首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   415篇
  免费   2篇
  国内免费   8篇
安全科学   11篇
废物处理   28篇
环保管理   44篇
综合类   50篇
基础理论   71篇
污染及防治   155篇
评价与监测   39篇
社会与环境   27篇
  2023年   5篇
  2022年   9篇
  2021年   20篇
  2020年   5篇
  2019年   3篇
  2018年   18篇
  2017年   20篇
  2016年   28篇
  2015年   16篇
  2014年   22篇
  2013年   40篇
  2012年   23篇
  2011年   30篇
  2010年   23篇
  2009年   20篇
  2008年   23篇
  2007年   23篇
  2006年   14篇
  2005年   17篇
  2004年   9篇
  2003年   10篇
  2002年   10篇
  2001年   4篇
  2000年   1篇
  1999年   2篇
  1998年   1篇
  1997年   2篇
  1996年   4篇
  1995年   2篇
  1993年   1篇
  1992年   2篇
  1991年   3篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1986年   3篇
  1985年   2篇
  1979年   1篇
  1977年   1篇
  1975年   1篇
  1967年   1篇
  1963年   1篇
排序方式: 共有425条查询结果,搜索用时 31 毫秒
361.
In spite of its outstanding ecological and touristic importance the Ria Formosa Lagoon shows signs of anthropogenic pollution. Nonetheless, until the present survey no studies had ever documented the measurement of natural and pharmaceutical estrogens (17β-estradiol, estrone, and 17α-ethynylestradiol), xenoestrogenic industrial pollutants (4-octylphenol, 4-nonylphenol, and their mono and diethoxylates and bisphenol A), phytoestrogens (formononetin, biochanin A, daidzein, genistein), and sitosterol in this area. The 17 compounds measured herein are known as endocrine disrupters (EDCs) and act over the endocrine system even in few amounts (ng L?1–μg L?1). Thus to conclude about the influx of EDCs in the lagoon, water samples were taken every 2 months, during 1 year (2010), in low tide at nine sites distributed along the coastline. Water samples (1 L) were preconcentrated in the Oasis HLB cartridges and cleaned in silica cartridges before their analysis by GC-MS. Data showed the ubiquitous presence of potentially hazardous amounts of estrogens (particularly of ethynylestradiol, up to 24.3 ng L?1), nonylphenol (up to 547 ng L?1), and sitosterol (up to 12,300 ng L?1), mainly in summer, suggesting that the increase of the local number of inhabitants (tourists), the rise of the water temperature (up to 26 °C), and the blooming of local flora may interfere with the water quality parameters. This makes the lagoon a potential model to study. Taking into account the data, it was concluded that there are conditions for the occurrence of endocrine disruption in aquatic animals, even in areas included in the natural park of the Formosa. Besides, both the high amounts of un-ionized ammonia (up to 0.3 mg L?1) and phosphates (up to 1.6 mg L?1) my pose risks for local fauna and humans.  相似文献   
362.
Wan-Kuen Jo  Chang-Hee Yang   《Chemosphere》2009,77(2):236-241
Unlike previous photocatalytic oxidation (PCO) studies incorporated with adsorption, this study investigates the feasibility of applying a tandem PCO-adsorption hybrid technique regarding low-level monoaromatic compound removal. The PCO efficiencies decreased as the hydraulic diameter (HD) increased. A PCO reactor of a medium HD size was selected for further experiments. Under conditions relevant to the use of the PCO system, the CO level measured during the PCO process was minimal in comparison to indoor CO levels. Trace level formations of formaldehyde and acetaldehyde were observed during the photocatalytic process, but these compounds were undetectable at the activated carbon unit outlet. The degradation efficiencies, obtained from the PCO unit, exhibited a dependence on both the inlet concentration (IC) and relative humidity (RH), whereas those from the PCO-adsorption hybrid system did not. Under specific conditions, the PCO unit presented a high degradation efficiency of close to, or exceeding 90%, in regards to ethyl benzene, o-xylene, and m,p-xylene. However, the benzene air concentrations, after being treated by the PCO unit, substantially exceeded the USEPA inhalation reference concentration guideline of 30 μg m−3 (corresponding to 0.01 ppm). In contrast, the PCO-adsorption hybrid system presented a high removal efficiency of close to 100% regarding all compounds, regardless of the IC or RH range. Consequently, it is suggested that the PCO-adsorption hybrid system has a synergistic advantage of photocatalysis and adsorption in regards to the BTEX elimination process.  相似文献   
363.
Defining Chlorophyll-a Reference Conditions in European Lakes   总被引:2,自引:0,他引:2  
The concept of “reference conditions” describes the benchmark against which current conditions are compared when assessing the status of water bodies. In this paper we focus on the establishment of reference conditions for European lakes according to a phytoplankton biomass indicator—the concentration of chlorophyll-a. A mostly spatial approach (selection of existing lakes with no or minor human impact) was used to set the reference conditions for chlorophyll-a values, supplemented by historical data, paleolimnological investigations and modelling. The work resulted in definition of reference conditions and the boundary between “high” and “good” status for 15 main lake types and five ecoregions of Europe: Alpine, Atlantic, Central/Baltic, Mediterranean, and Northern. Additionally, empirical models were developed for estimating site-specific reference chlorophyll-a concentrations from a set of potential predictor variables. The results were recently formulated into the EU legislation, marking the first attempt in international water policy to move from chemical quality standards to ecological quality targets.  相似文献   
364.
Zeolitic sorbents for CO2 adsorption were prepared from waste coal fly ash (FA) through hydrothermal treatment at various ratios of NaOH/FA and NaAlO2/FA, including an initial alkali fusion step. The fusion step decomposed the fly ash into very small amorphous particulate zeolite forms. The fly ash was converted to Na-P1 type with a NaOH/FA ratio of 0.5 and Na-A type with a NaAlO2/FA ratio of 0.53. The product properties were affected by the reaction temperature: Na-P1 and Na-A types were formed at 100°C. Temperatures above 140°C led to the formation of more sodalite because of the redissolving and recrystallization of zeolite crystals. Alkali metal and alkaline earth metal cations were impregnated in the synthesized Na-P1 and Na-A zeolite through an ion-exchange method. The completed zeolitic sorbents were applied to the adsorption of low-level CO2. As a result of the experiments, calcium ions were found to be the best for CO2 adsorption owing to their electrostatic behavior and acid-base interaction.  相似文献   
365.

Introduction and background

Primary producers play critical structural and functional roles in aquatic ecosystems; therefore, it is imperative that the potential risks of toxicants to aquatic plants are adequately assessed in the risk assessment of chemicals. The standard required macrophyte test species is the floating (non-sediment-rooted) duckweed Lemna spp. This macrophyte species might not be representative of all floating, rooted, emergent, and submerged macrophyte species because of differences in the duration and mode of exposure; sensitivity to the specific toxic mode of action of the chemical; and species-specific traits (e.g., duckweed's very short generation time).

Discussion and perspectives

These topics were addressed during the workshop entitled “Aquatic Macrophyte Risk Assessment for Pesticides” (AMRAP) where a risk assessment scheme for aquatic macrophytes was proposed. Four working groups evolved from this workshop and were charged with the task of developing Tier 1 and higher-tier aquatic macrophyte risk assessment procedures. Subsequently, a SETAC Advisory Group, the Macrophyte Ecotoxicology Group (AMEG) was formed as an umbrella organization for various macrophyte working groups. The purpose of AMEG is to provide scientifically based guidance in all aspects of aquatic macrophyte testing in the laboratory and field, including prospective as well as retrospective risk assessments for chemicals. As AMEG expands, it will begin to address new topics including bioremediation and sustainable management of aquatic macrophytes in the context of ecosystem services.  相似文献   
366.
Application of fluidization to separate packaging waste plastics   总被引:1,自引:0,他引:1  
The objective of the experimental work described in this paper is the study of the separation of PS (polystyrene) from PET (polyethylene terephthalate) and PVC (polyvinyl chloride) from drop-off points using a fluidized bed separator. This is a low-cost process commonly used in the hydro-classification of mineral ores. Firstly, experimental tests were carried out with artificial granulated samples with different grain sizes, types and sources of plastic ("separability tests"). The particle settling velocities were determined under different operating conditions. Then, based on the results, the laboratory tests continued with real mixtures of waste plastics ("separation tests") and the efficiency of the process was evaluated. From a PET-rich mixture, a concentrate of PS with a 75% grade in PS was produced while the underflow was quite clear from PS (grade less than 0.5% in PS).  相似文献   
367.
A procedure based on solid-phase microextraction (SPME) and gas chromatography coupled with mass spectrometry (GC-MS) was developed and validated in order to analyse 10 phenols in water samples. The optimised conditions were obtained using polyacrylate fibre (PA), 20ml of sample volume, 10% NaCl, pH 4.0 and direct extraction at 35 degrees C and 1000rpm, for 40min. The linear range and quantification limits for these compounds by SPME-GC-MS were defined. An evaluation of the main uncertainty sources of this method is included, which allows expanded uncertainties in the 9.4-35% range for the majority of the compounds. The main source of uncertainty is associated with matrix effects. The validated method is suitable for monitoring the production and distribution of potable water and was used, in field trials, for the analysis of samples from main intakes of water (surface or underground) and from water supply system of a large area (Lisbon and neighbour municipalities).  相似文献   
368.
Chemical monitoring of water quality on a total of 16 rivers in the Azores archipelago (Portugal), since 2003, made it possible to identify the major pressures and spatial geochemical variations along main course of the rivers. River water pollution is to a large extent associated to point sources, namely domestic wastewater discharges, especially in urban areas, and diffuse sources, associated with pasture land, and explain the high values on BOD(5) and nutrients (P and N). Heavy metals and metalloids, as well as hydrocarbons and pesticides, are generally under the detection limits of the analytical methods. Generally, river water reflects pollution loads according to a simple model, derived from land use in the watershed: in the upper part conditions are pristine, in the intermediate portion of the basin pasture land dominates and near the coast urban discharges are increasingly important. Results stress the role that an approach based on the watershed scale, coupled with land use management measures, are crucial to water management procedures and a successful WFD implementation in small river basin districts like the Azores. The paper also shows the need for full compliance regarding EU directives on urban wastewater and nitrate pollution due to agriculture.  相似文献   
369.
The Mondego River estuary demonstrates signs of pollution, but the levels of endocrine disrupting compounds (EDCs), such as the natural (17β-estradiol and estrone) and pharmaceutical (17α-ethynylestradiol) estrogens, xenoestrogenic industrial pollutants (4-octylphenol, 4-nonylphenol, and their mono- and diethoxylates and bisphenol A), phytoestrogens (formononetin, biochanin A, daidzein, and genistein), and sitosterol were either poorly or never measured in this area. Thus, to conclude about the influx of EDCs in this estuary, water samples were taken every 2 months, during 1 year (2010) in low tide, at eight sites distributed along the estuary. Water samples (1 L) were preconcentrated in the Oasis HLB cartridges and cleaned in silica cartridges before their analysis by GC-MS. In summer, potentially hazardous amounts of estrogens (≈26 ng L?1), alkylphenols (≈11.5 μg L?1), alkylphenolethoxylates (≈13 μg L?1), and phytoestrogens (≈5.6 μg L?1) were measured. These data suggest that changes in the hydrodynamics of the estuary coupled with the increase of water temperatures interfere with the amount of EDCs in the water. Complementary physicochemical parameters also point to high levels of anthropogenic pollution in this area. Globally, the estrogenic load, expressed in ethynylestradiol equivalents, attained 71.8 ng L?1 demonstrating that, all together, the measured EDCs pose important health risks for both biota and humans.  相似文献   
370.
An observational field study was conducted to assess the feasibility of a community duplicate diet collection method; a dietary monitoring tool that is population-based. The purpose was to establish an alternative procedure to duplicate diet sampling that would be more efficient for a large, defined population, e.g., in the National Children's Study (NCS). Questionnaire data and food samples were collected in a residence so as not to lose the important component of storage, preparation, and handling in a contaminated microenvironment. The participants included nine Hispanic women of child bearing age living in Apopka, FL, USA. Foods highly consumed by Hispanic women were identified based on national food frequency questionnaires and prioritized by permethrin residue concentrations as measured for the Pesticide Data Program. Participants filled out questionnaires to determine if highly consumed foods were commonly eaten by them and to assess the collection protocol for the food samples. Measureable levels of permethrin were found in 54% of the samples. Questionnaire responses indicated that the collection of the community duplicate diet was feasible for a defined population.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号