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   175篇
  免费   0篇
安全科学   5篇
废物处理   17篇
环保管理   18篇
综合类   13篇
基础理论   48篇
污染及防治   44篇
评价与监测   18篇
社会与环境   12篇
  2021年   2篇
  2020年   6篇
  2019年   4篇
  2018年   15篇
  2017年   7篇
  2016年   6篇
  2015年   7篇
  2014年   3篇
  2013年   12篇
  2012年   21篇
  2011年   13篇
  2010年   12篇
  2009年   6篇
  2008年   7篇
  2007年   5篇
  2006年   2篇
  2005年   3篇
  2004年   5篇
  2003年   4篇
  2002年   2篇
  2001年   8篇
  2000年   1篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1995年   2篇
  1993年   1篇
  1992年   1篇
  1986年   1篇
  1984年   1篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1977年   2篇
  1976年   2篇
  1975年   1篇
  1961年   1篇
  1958年   1篇
  1956年   1篇
  1938年   1篇
  1937年   1篇
排序方式: 共有175条查询结果,搜索用时 31 毫秒
91.
Emission of metals in the urbanenvironment is a growing concern throughout theworld. In order to identify metal emissionssources in the Stockholm metropolitan region, amethod for detailed mapping of roof coatings andother urban land covers has been developedconducted. High accuracy area calculation ofcopper roof coatings based on scanned aerialphotography was used. The geometric resolution ofthe digital photographs was 0.4 metre. Imagelayers with identified copper roof objects weremerged with a digital elevation model of 1 metregeometric resolution. The slope gradient for eachroof was calculated in order to account for slopein the calculation of roof areas. In total,622,590 m2 of copper roofs were accounted,of which 176,845 m2 and 447,745 m2represent new and patinated copper respectively.The number of copper roofs larger than 1,000m2 was 142. Applying corrosion and runoffrates on these figures, a yearly Cu flux ofapproximately 1,200 kg in Stockholm may bederived from copper coated building.  相似文献   
92.
A method for investigating in-situmethylation and mobility of mercury has beendeveloped and applied to forest soil. The methodis based on additions of stable 199Hgisotopes to forest soil plots followed bysampling and analysis of isotope ratios of totalmercury and MeHg using ICP-MS. Initial resultsindicate that a fraction (30%) of the mercuryadded to the forest soils is immobilised over atime scale of 16 months. A small but significantfraction of the mercury is methylated during thesame time scale. Higher methylation rates werefound in wetland soil than in dry forest podzolsoil.  相似文献   
93.
The atmosphere remains the major source of mercuryin Swedish ecosystems. Since the late eighties,atmospheric emissions of mercury have drasticallydecreased in Europe. Wet deposition of mercury hasdecreased over the last decade but still exhibitsa clear south-to-north gradient, greatlyinfluenced by source areas in northern and centralEurope. The decreases in emissions can beattributed to both direct measures to close knownpoint sources and a declining economy and energyconsumption in many East European countries.Further reductions of mercury emissions willrequire that other source categories such asindirect emissions from mercury-containingproducts and crematories are be considered.  相似文献   
94.
The current study investigated oxidative stress parameters (enzymes activities, metallothionein content and lipid peroxidation) in freshwater fish, Oreochromis niloticus, tilapia exposure to Monjolinho River (in 4 months of year: January, April, July and November). One critical site in Monjolinho River (site B) was assessed in comparison to a reference site (site A). Water pH and oxygen concentration was lower than that recommended by CONAMA (Brazilian National Environmental Committee), resolution 357/2005 for protection of aquatic communities, and ammonium and the metals Cu, Zn, Mn and Fe (on all months) concentrations were higher than the maximum concentration recommended. Glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were significantly decreased in liver and muscle in tilapia from Monjolinho River, throughout the year, in relation to reference except in gills that SOD activity increased. Glutathione S-transferase (GST) activity was significantly increased in liver of the tilapia from Monjolinho River in all sites, in relation to reference except in gills that GST activity increased in July and decreased in November, suggesting that GST activity could be induced to neutralize the pollutants toxicity. On the other hand, GST activity was significantly decreased in white muscle indicating a toxic effect of pollutants, resulting in a decreased ability of tilapia to perform defense reactions associated to GSTs. The decrease of catalase (CAT) activity in gills of the O. niloticus together with the increase of SOD activity, could explain the increased lipid peroxidation (LPO) level in this organ. Metallothionein levels in liver and gills were significantly high in all sites. Results indicate that the exposure to metals caused severe damage to tissues; despite the consensually assumed antioxidant induction as a sign of exposure to contaminants the effects seem in part to be mediated by suppression of antioxidant system with SOD, CAT and GPx as potential candidates for tissues toxicity biomarkers of pollutants.  相似文献   
95.
Although a number of comprehensive reviews have examined global ecosystem services (ES), few have focused on studies that assess urban ecosystem services (UES). Given that more than half of the world’s population lives in cities, understanding the dualism of the provision of and need for UES is of critical importance. Which UES are the focus of research, and what types of urban land use are examined? Are models or decision support systems used to assess the provision of UES? Are trade-offs considered? Do studies of UES engage stakeholders? To address these questions, we analyzed 217 papers derived from an ISI Web of Knowledge search using a set of standardized criteria. The results indicate that most UES studies have been undertaken in Europe, North America, and China, at city scale. Assessment methods involve bio-physical models, Geographical Information Systems, and valuation, but few study findings have been implemented as land use policy.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-014-0504-0) contains supplementary material, which is available to authorized users.  相似文献   
96.
Wind selectivity of migratory flight departures in birds   总被引:5,自引:0,他引:5  
Optimal migration theory predicts that birds minimizing the overall time of migration should adjust stopover duration with respect to the rate of fuel accumulation. Recent theoretical developments also take into account the wind situation and predict that there is a time window (a set of days) during which birds should depart when assisted by winds but will not do so if there are head winds. There is also a final day when birds will depart irrespective of wind conditions. Hence, the wind model of optimal migration theory predicts that birds should be sensitive to winds and that there should be a correlation between departures and winds blowing towards the intended migration direction. We tested this assumption by tracking the departures of radio-tagged passerines during autumn migration in southern Sweden. Our birds were moderately to very fat when released and therefore energetically ready for departure. There was a significant correlation between direction of departure and wind direction. We also found that during days when birds departed there was a significantly larger tail wind component than during days when birds were present but did not depart. Our results show that passerines do take the current wind situation into account when departing on migratory flights. We also briefly discuss possible clues that birds use when estimating wind direction and strength. The inclusion of wind is an important amendment to optimal migration theory of birds and should be explored further. Received: 1 March 1999 / Received in revised form: 4 October 1999 / Accepted: 16 October 1999  相似文献   
97.
Environmental Management - Natural resource managers urgently need to adapt to climate change, and extension services are increasingly using targeted communication campaigns to promote individual...  相似文献   
98.
This study reports the optimization of a binary dispersive liquid-liquid microextraction method for the determination of iprodione, procymidone, and chlorflurenol by gas chromatography mass spectrometry. The study was aimed at using two extraction solvents to increase the extraction efficiency of all analytes. The binary solvents recorded results higher than the mono-solvents. After examining the effects of main experimental parameters and their interactions by analysis of variance, 200 μL of binary mixture (dichloromethane and 1,2-dichloroethane), 2.5 mL of ethanol, and 15 s vortex were obtained as optimum parameters. The detection and quantification limits calculated for the analytes were found to be between 0.30–1.6 and 1.0–5.3 ng/mL, respectively. Enhancement in detection power calculated as a ratio of the binary extraction detection limit to the detection limit of direct GC-MS analysis was 105-, 214-, and 233-fold for chlorflurenol, iprodione, and procymidone, respectively. In order to check the accuracy of the developed method, recovery study was performed. Water sampled from a lake and two wastewater samples from treatment facilities were spiked at two concentrations, and the percent recovery calculated for the samples ranged between 87 and 116%. These results confirmed the suitability of the method to real samples for accurate determination of the analytes at trace levels.  相似文献   
99.

A growing body of literature argues that subjective factors can more accurately explain individual adaptation to climate change than objective measurers of adaptive capacity. Recent studies have shown that personal belief in climate change and affect are much better in explaining climate awareness and action than income, education or gender. This study focuses on the process of individual adaptation to climate change. It assesses and compares the influence of cognitive, experiential and structural factors on individuals’ views and intentions regarding climate change adaptation. Data from this study comes from a survey with 836 forest owners in Sweden. Ordinal and binary logistic regression was used to test hypotheses about the different factors. Results show that cognitive factors—namely personal level of trust in climate science, belief in the salience of climate change and risk assessment—are the only statistically significant factors that can directly explain individuals’ intention to adapt to climate change and their sense of urgency. Findings also suggest that structural or socio-demographic factors do not have a statistically significant influence on adaptation decision-making among Swedish forest owners. The study also offers valuable insights for communication interventions to promote adaptation. Findings strongly suggest that communication interventions should focus more strongly on building trust and addressing stakeholders’ individual needs and experiences.

  相似文献   
100.
Polycyclic aromatic hydrocarbons are known for their carcinogenic and mutagenic effects on human health. This therefore calls for the regulation of their concentrations in air, water, and soil. Naphthalene as the simplest in structure of the polycyclic aromatic hydrocarbons is mainly used as a starter material for other chemicals but also has impacts on human health. A method is therefore proposed for the determination of naphthalene in water samples by gas chromatography mass spectrometry after liquid-liquid extraction. The extraction method was optimized to improve the extraction output, thereby lowering the limit of detection. The limits of detection and quantification obtained for naphthalene were 4.4 and 14.6 ng mL?1, respectively. Deuterated anthracene was used as internal standard to enhance the precision of the method, for which a relative standard deviation of 4.3% was obtained. The percent recovery of naphthalene obtained from tap water was ranged between 93.8 and 102.2.  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