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 15 毫秒
111.
The design of heating, ventilation and air conditioning systems is still a challenging engineering task which requires experienced and informed decision-making. These systems have a great energy-saving potential at the system level rather than at the level of the individual products of which they are composed. European environmental product policies have been very useful in facilitating a homogeneous rating scheme which can be used to compare the energy performance of different products that provide the same service. This paper proposes a simplified design method which uses the performance of components that are regulated by European product policies to obtain the overall performance of heating systems in residential buildings. It is a flexible method and allows different product configurations to be assessed so as to optimise the system performance during the design phase. The method is tested on a real case study with domestic hot water and space heating systems. The case study shows the potential for improving the heating systems according to the performance levels of its products currently available in the market. Results of the domestic hot water system show that upgrading its storage tank to the maximum energy class (A+) could bring the highest energy savings ( 4162 kWh/y).  相似文献   
112.
This work was aimed at finding materials that could be used as alternatives to lichens as air quality monitors since the high natural variability and the large amount of lichen collected are two drawbacks of the use of these organisms. Lichen Flavoparmelia caperata(L.) Hale was exposed in three different forms (transplant, detached from the substratum and as a biomass-ground and homogeneized) and compared to the planetree bark (Platanus hybrida Brot.), exposed as a biomass, and two organic synthetic materials (Chelex(R) 100 resin and cellulose acetate). Materials were exposed for two months in the winter, spring and summer, at three Portuguese coastal cities. The results showed that the airborne accumulations of Cu, Ni, Pb and Sr were partially dependent on the meteorological conditions but mainly dependent on the nature of the exposed material. The standard deviations of the synthetic materials or homogenized biomass were the same or greater than lichen transplants or detached. The accumulation by biological materials, of the four studied elements, was comparable to the lichen transplant accumulation. The replacement of the traditional transplants by the biomass was not considered advantageous, since their preparation is time-consuming. Therefore lichens remain the most suitable in biomonitoring studies. The exposure of detached lichen allows the accurate measurement of the exposed area/volume so it can be useful to relate atmospheric deposition rates with the lichen metal content. The synthetic materials accumulated Cu and Ni and should only be used as an alternative to traditional transplants when these are the elements of interest.  相似文献   
113.
Journal of Material Cycles and Waste Management - Waste water contaminated with inorganic mercury is considered a serious environmental problem, mainly due to the hazardous effects this contaminant...  相似文献   
114.

Background, aim, and scope  

Polycyclic aromatic hydrocarbons (PAHs) are often found in oily wastewaters. Their presence is usually the result of human activities and has a negative effect on the environment. One important step in addressing this problem is to evaluate the effectiveness of PAH removal by biological processes since these are the most cost-effective treatments known today. Many techniques are presently available for PAH determination in wastewaters. Solid phase microextracion (SPME) is known to be one of the most effective techniques for this purpose. When analyzing complex matrices with substances such as natural organic matter (NOM) and non-aqueous phase liquids (NAPL), it is important to differentiate the free dissolved PAH from matrix-bonded PAH. PAHs associated with the bonded fraction are less susceptible to biological treatment. The present study concerns the development of a simple and suitable methodology for the determination of the freely dissolved and the total fraction of PAHs present in oily wastewaters. The methodology was then applied to an oily wastewater from a fuel station retention basin.  相似文献   
115.
The presence of antibiotics in the aquatic environment has raised concerns due to the potential risk for the emergence or persistence of antibiotic resistance. Antibiotics are often poorly degraded in conventional wastewater treatment plants. In this study, sonolysis at 520 kHz and 92 W L−1 was used for the degradation of the fluoroquinolone antibiotic ciprofloxacin. In a first experiment at pH 7, 57% of the ciprofloxacin (15 mg L−1) was degraded after 120 min of ultrasonic irradiation at 25 °C. pH proved to be an important parameter determining the degradation rate, since the pseudo first order degradation constant increased almost fourfold when comparing treatment at pH 7 (0.0058 min−1) and pH 10 (0.0069 min−1) with that at pH 3 (0.021 min−1). This effect can be attributed to the degree of protonation of the ciprofloxacin molecule. The BOD/COD ratio of the solutions, which is a measure for their biodegradability, increased from 0.06 to 0.60, 0.17, and 0.18 after 120 min of irradiation depending on the pH (3, 7, and 10, respectively). The solution treated at pH 3 can even be considered readily biodegradable (BOD/COD > 0.4). The antibiotic activity against Escherichia coli (G−) and Bacillus coagulans (G+) of the treated solutions also reduced after sonolysis. The highest decrease was again found when irradiated at pH 3. In contrast, ecotoxicity of the solutions to the alga Pseudokirchneriella subcapitata increased 3- to 10-fold after 20 min of treatment, suggesting the formation of toxic degradation products. The toxicity slowly diminished during further treatment.  相似文献   
116.
CORINAIR atmospheric emission inventories are frequently used input data for air quality models with a domain situated in Europe. In CORINAIR emission inventories, sources are broken down over 11 major source categories. This paper presents spatial surrogates for the disaggregation of CORINAIR atmospheric emission inventories for input of air pollutants and particulate matter to grid or polygon based air quality model domains inside Europe. The basis for the disaggregation model was the CLC2000 land cover data to which statistical weights were added. Weights were population census data for residential emissions, employment statistics for agricultural and industrial area emissions, livestock statistics for ammonia emissions and annual aircraft movements for emissions realized by air transport. Additional road and off-road network information was used to disaggregate emissions realized by traffic. A comparison of top down produced emission estimates with spatially resolved national emission data for The Netherlands and the United Kingdom gave confidence in the present spatial surrogates as a tool for the top down production of atmospheric emission maps. Explained variance at a spatial resolution of 5 km was >70% for CO, NMVOC and NOx, >60% for PM10 and almost 50% for SO2.  相似文献   
117.
Distribution of endocrine disruptors in the Mondego River estuary, Portugal   总被引:2,自引:0,他引:2  
Recent studies in the Mondego River estuary demonstrated signs of pollution in the area, but the nature of the contamination remains unexplored. Because there seems to be any studies in that zone checking for the simultaneous presence of xenoestrogenic endocrine disrupting compounds, either of animal (estradiol and estrone), vegetal (daidzein, genistein and biochanin A), pharmaceutical (17alpha-ethynylestradiol) or industrial (bisphenol A, 4-octylphenol, 4-nonylphenol) origins, the main objective of this study was to investigate their presence, in every year season and at eight points along the estuarine gradient. For this propose, water samples (2 L) were collected in high and low tides, preconcentrated in the Oasis HLB cartridges and cleaned in silica cartridges before their analysis by HPLC-DAD and GC-MS. The current data showed the absence of contamination by animal or pharmaceutical estrogens and by alkylphenols, but demonstrated the presence of high levels of phytoestrogens (up to 1.1 mug/L) and of bisphenol A (up to 880.0 ng/L). Because these two chemicals existed in high environmental concentrations in the most upstream sampling station, and taking in account that these pollutants may additively contribute to endocrine disruption, namely on fish, it was concluded that at least this particularly area of the Mondego estuary deserves continuous monitoring programmes.  相似文献   
118.
The potential use of metallothioneins (MTs) as biomarkers of trace metal contamination was evaluated for the first time in the Algerian mouse (Mus spretus). Mice were collected seasonally in an abandoned mining area (Aljustrel) and in a reference area, both located in southern Portugal. MT levels were quantified in liver and kidney by differential pulse polarography and hepatic elemental concentrations (Mn, Fe, Cu, Zn, Se) were determined by particle-induced X-ray emission. Hepatic iron and selenium concentrations were elevated in mice from Aljustrel mine when compared to reference animals. MTs levels were averagely higher in mice from Aljustrel than those originated from the reference area. A season-dependent significant effect was found on the hepatic and renal MT concentrations, characterized by higher levels in winter and lower in autumn. In contaminated mice positive relationship between liver elemental contents (Cu in autumn and Fe in winter) and MTs were found. The seasonal variation of MT suggests that probably physiological and environmental factors could influence hepatic and renal MT induction. Results seem to imply that some environmental disturbance occur in the vicinity of the Aljustrel mine. Therefore, for the management purposes MT levels should be followed in liver of M. spretus, especially in winter. Furthermore, other physiological factors that could influence MT expression and turnover in Algerian mouse should also be monitored.  相似文献   
119.
Monitoring of immission of persistent organic pollutants in the industrialized area of Volta Redonda (V.R.) and in the National Park of Itatiaia (PNI) in southeast Brazil was performed using an endemic Bromeliad species as biomonitor and measuring total deposition rates on funnels covered with polyurethane foams. Samples were collected during 78 days in V.R. and 95 days in PNI in winter (dry season, June-August 2003) and during 114 days in both areas in summer (rainy season, December 2003-February 2004). The PCDD/PCDF deposition rates ranged from 0.10 to 1.9 pg WHO-TEQ/(m2 day) in winter and from 0.11 to 2.2 pg WHO-TEQ/(m2 day) in summer. Deposition rates found in V.R. in summer were four- to ninefold higher than those measured in PNI, while in winter deposition rates in both regions were in the same range. Deposition rates in V.R. in summer were about five fold lower than those measured in 1996. PCDD/PCDF levels in biomonitor samples were between 0.95 and 14.6 ng WHO-TEQ/kg d.m. in winter and between 2.2 and 5.2 ng WHO-TEQ/kg d.m. in summer. In winter, concentrations found in V.R. were up to 11 times higher than those found in PNI, while in summer the levels measured in both areas were comparable. The homologue and isomer profiles found in the deposition as well as in the biomonitor samples from V.R. indicate that steel production is the main source of contamination in the region, whereas in PNI, the long range transport of these pollutants is the predominant contamination pathway.  相似文献   
120.
Muscle, liver and stomach contents of 64 blue sharks and 52 swordfishes, caught between September 2004 and February 2005 near the Azores (area A) and the Equator (area E), were analysed for mercury and selenium. Levels of mercury were relatively high (blue shark: 0.032-2.5microgg(-1); swordfish: 0.031-9.8microgg(-1)) and comparable to values reported in the literature. However, mercury and organic mercury concentrations in muscle and liver of specimens from E were significantly higher than those from A. A similar trend was registered in stomach contents, suggesting higher uptake of Hg in specimens from E. This difference was also observed in the relationship between concentration in muscle and size, indicating a higher accumulation rate in specimens from E. The accumulation of Se in the liver of both species showed a positive correlation with inorganic mercury concentrations, pointing to a detoxifying mechanism of organic mercury in these species through Se-Hg liasons.  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