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811.
Abu-Allaban M Gillies JA Gertler AW Clayton R Proffitt D 《Environmental monitoring and assessment》2007,132(1-3):155-163
A source apportionment study was carried out to estimate the contribution of motor vehicles to ambient particulate matter
(PM) in selected urban areas in the USA. Measurements were performed at seven locations during the period September 7, 2000
through March 9, 2001. Measurements included integrated PM2.5 and PM10 concentrations and polycyclic aromatic hydrocarbons (PAHs). Ambient PM2.5 and PM10 were apportioned to their local sources using the chemical mass balance (CMB) receptor model and compared with results obtained
using scanning electron microscopy (SEM). Results indicate that PM2.5 components were mainly from combustion sources, including motor vehicles, and secondary species (nitrates and sulfates).
PM10 consisted mainly of geological material, in addition to emissions from combustion sources. The fractional contributions of
motor vehicles to ambient PM were estimated to be in the range from 20 to 76% and from 35 to 92% for PM2.5 and PM10, respectively. 相似文献
812.
A number of policy measures have been activated in India in order to control the levels of air pollutants such as particulate
matter, sulphur dioxide (SO2) and nitrogen dioxide (NO2). Delhi, which is one of the most polluted cities in the world, is also going through the implementation phase of the control
policies. Ambient air quality data monitored during 2000 to 2003, at 10 sites in Delhi, were analyzed to assess the impact
of implementation of these measures, specifically fuel change in vehicles. This paper presents the impact of policy measures
on ambient air quality levels and also the source apportionment. CO and NO2 concentration levels in ambient air are found to be associated with the mobile sources. The temporal variation of air quality
data shows the significant effect of shift to CNG (Compressed Natural Gas) in vehicles. 相似文献
813.
H. McLeod I. H. Langford A. P. Jones J. R. Stedman R. J. Day I. Lorenzoni I. J. Bateman 《Regional Environmental Change》2000,1(2):78-85
This paper investigates the distribution of three common air pollutants, sulphur dioxide, nitrogen dioxide and fine particulates
(PM10), in England and Wales with respect to social class, ethnicity and population density. A multilevel model is used to demonstrate
regional differences in the social distribution of pollution. The results show that, allowing for ethnicity and population
density, there are different relationships between socio-economic status and exposure to air pollution within different regions
in England and Wales. These differences suggest that national legislation introduced to reduce air pollution levels may give
rise to environmental injustice, with geographical and social differences in the costs and benefits arising to the population
due to such legislation.
Received: 24 February 1999 / Accepted: 2 September 1999 相似文献
814.
基于Models-3的自修正空气质量预报系统及其效果检验 总被引:1,自引:0,他引:1
本文介绍了一个以Models-3为基础的自动化空气质量数值预报系统,该系统通过Gambas、Yabasic和R语言等工具进行开发,集成WRF-SMOKE-CMAQ三个模式,可通过监测数据进行自动修正,完成空气质量业务数值预报,并将结果发布到Web服务器上进行呈现。该系统对硬件的要求较低,将部署于一台DELL Optiplex 9010工作站上,设置6km—2km双层嵌套,进行成都市空气质量数值预报。本文分析了成都市2014年1月1日至2014年12月31日的空气质量数值预报结果,评价系统对成都市NO_2、SO_2、PM_(10)、PM_(2.5)、O_3、CO以及空气质量指数(AQI)的预报效果。结果显示,系统对于成都市2014年空气质量变化情况趋势的预报效果较好,302天有效预报中,24小时直接预报的空气质量等级准确率为58.27%,AQI预报相关系数0.71,观测值自动修正预报对24小时空气质量预报具有明显改善效果,使其等级预报准确率达到64.9%,相关系数提高到0.89。 相似文献
815.
Ricardo Cisneros Andrzej Bytnerowicz 《Environmental pollution (Barking, Essex : 1987)》2010,158(10):3261-3271
Two-week average concentrations of ozone (O3), nitric acid vapor (HNO3) and ammonia (NH3) were measured with passive samplers during the 2002 summer season across the central Sierra Nevada Mountains, California, along the San Joaquin River drainage. Elevated concentrations of the pollutants were determined with seasonal means for individual sites ranging between 62 and 88 ppb for O3, 1.0-3.8 μg m−3 for HNO3, and 2.6-5.2 μg m−3 for NH3. Calculated O3 exposure indices were very high, reaching SUM00-191 ppm h, SUM60-151 ppm h, and W126-124 ppm h. Calculated nitrogen (N) dry deposition ranged from 1.4 to 15 kg N ha−1 for maximum values, and 0.4-8 kg N ha−1 for minimum values; potentially exceeding Critical Loads (CL) for nutritional N. The U.S., California, and European 8 h O3 human health standards were exceeded during 104, 108, and 114 days respectively, indicating high risk to humans from ambient O3. 相似文献
816.
Many regions worldwide are experiencing rapid urbanization, and often along with growth in the local economy and population comes worsening air quality. Such regions typically find that addressing the additional challenge of polluted air is difficult. This paper reports the results of an assessment of the present health and related economic costs of poor air quality in the San Joaquin Valley of California. Further, it suggests how such assessments can support strategies to pursue pollution reductions that offer the largest near-term gains, by rigorously modeling the associations between pollution levels, demographic groups, and recognized adverse health effects. 相似文献
817.
Assessing the ecosystem service of air pollutant removal by urban trees in Guangzhou (China) 总被引:7,自引:0,他引:7
In Chinese cities, air pollution has become a serious and aggravating environmental problem undermining the sustainability of urban ecosystems and the quality of urban life. Besides technical solutions to abate air pollution, urban vegetation is increasingly recognized as an alternative ameliorative method by removing some pollutants mainly through dry deposition process. This paper assesses the capability and monetary value of this ecosystem service in Guangzhou city in South China. The results indicated an annual removal of SO(2), NO(2) and total suspended particulates at about 312.03Mg, and the benefits were valued at RMB90.19 thousand (US$1.00=RMB8.26). More removal was realized by recreational land use due to a higher tree cover. Higher concentration of pollutants in the dry winter months induced more removal. The lower cost of pollution abatement in China generated a relatively subdued monetary value of this environmental benefit in comparison with developed countries. Younger districts with more extensive urban trees stripped more pollutants from the air, and this capacity was anticipated to increase further as their trees gradually reach final dimensions and establish a greater tree cover. Tree cover and pollutant concentration constitute the main factors in pollutant removal by urban trees. The efficiency of atmospheric cleansing by trees in congested Chinese cities could be improved by planting more trees other than shrubs or grass, diversifying species composition and biomass structure, and providing sound green space management. The implications for greenery design were discussed with a view to maximizing this ecosystem service in Chinese cities and other developing metropolises. 相似文献
818.
G. Hugh Sidaway 《The Environmentalist》2008,28(3):327-330
The 11th report of COMARE (Committee on Medical Aspects of Radiation in the Environment) established that the incidence of
some childhood cancers, including leukaemia, is inversely related to population density in England, Wales and Scotland, and
is particularly high in Buckinghamshire. Using a photographic archive survey, the present paper notes that population density
is also inversely related to overhead wire domestic electricity supply in Buckinghamshire. Factors associated with domestic
electricity supply may be relevant to the geographical distribution of some childhood cancers. 相似文献
819.
Urban sprawl and air quality in large US cities 总被引:3,自引:0,他引:3
Stone B 《Journal of environmental management》2008,86(4):688-698
This study presents the results of a paper of urban spatial structure and exceedances of the 8-h national ambient air quality standard for ozone in 45 large US metropolitan regions. Through the integration of a published index of sprawl with metropolitan level data on annual ozone exceedances, precursor emissions, and regional climate over a 13-year period, the association between the extent of urban decentralization and the average number of ozone exceedances per year, while controlling for precursor emissions and temperature, is measured. The results of this analysis support the hypothesis that large metropolitan regions ranking highly on a quantitative index of sprawl experience a greater number of ozone exceedances than more spatially compact metropolitan regions. Importantly, this relationship was found to hold when controlling for population size, average ozone season temperatures, and regional emissions of nitrogen oxides and volatile organic compounds, suggesting that urban spatial structure may have effects on ozone formation that are independent of its effects on precursor emissions from transportation, industry, and power generation facilities. 相似文献
820.