全文获取类型
收费全文 | 555篇 |
免费 | 48篇 |
国内免费 | 99篇 |
专业分类
安全科学 | 52篇 |
废物处理 | 4篇 |
环保管理 | 42篇 |
综合类 | 285篇 |
基础理论 | 43篇 |
污染及防治 | 121篇 |
评价与监测 | 121篇 |
社会与环境 | 29篇 |
灾害及防治 | 5篇 |
出版年
2024年 | 1篇 |
2023年 | 23篇 |
2022年 | 13篇 |
2021年 | 12篇 |
2020年 | 21篇 |
2019年 | 14篇 |
2018年 | 19篇 |
2017年 | 18篇 |
2016年 | 22篇 |
2015年 | 23篇 |
2014年 | 45篇 |
2013年 | 21篇 |
2012年 | 41篇 |
2011年 | 47篇 |
2010年 | 36篇 |
2009年 | 42篇 |
2008年 | 39篇 |
2007年 | 31篇 |
2006年 | 23篇 |
2005年 | 10篇 |
2004年 | 19篇 |
2003年 | 11篇 |
2002年 | 15篇 |
2001年 | 17篇 |
2000年 | 12篇 |
1999年 | 18篇 |
1998年 | 19篇 |
1997年 | 19篇 |
1996年 | 7篇 |
1995年 | 21篇 |
1994年 | 15篇 |
1993年 | 5篇 |
1992年 | 13篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有702条查询结果,搜索用时 328 毫秒
501.
利用2019—2021年合肥市气象参数、颗粒物浓度、颗粒物化学组分、颗粒物散射系数、颗粒物粒径谱等的逐小时观测数据,分析了合肥市大气能见度变化趋势及其影响因素。结果表明,2019—2021年,合肥市能见度呈逐年上升的总体特征,并且在季节变化上呈现为夏高冬低,在日变化上呈现为午后最高、夜间最低。相关性分析结果显示,合肥市能见度与颗粒物浓度、相对湿度均呈显著负相关关系,且能见度与相对湿度的相关程度比与颗粒物浓度的相关程度高15.5%~219.2%。相对湿度是直接影响合肥市能见度的主要因素之一,而温度、风速对能见度的间接影响作用相对较小。能见度与颗粒物特性关系研究结果表明:能见度与水溶性离子的相关程度高于与碳质组分的相关程度;当能见度处于较低水平时,能见度与PM2.5主要组分浓度的相关性明显减弱,相对湿度、超细颗粒物占比、水溶性离子含量和碳质组分含量等因素对能见度的影响逐渐凸显;在较高PM2.5浓度环境条件下,颗粒物散射系数的显著变化是导致能见度降低的主要原因;小粒径颗粒物对合肥市大气能见度的影响程度相对较高,应优先大幅度降低PM1.0浓度。 相似文献
502.
François Bompay 《Atmospheric environment (Oxford, England : 1994)》1998,32(24):7250
During ETEX Meteo-France applied part of its emergency response system for critical events developped in the framework of the World Meteorological Organization environmental emergency response program. The atmospheric transport model used to forecast the evolution of a passive tracer is an eulerian model called MEDIA. In real time this model is driven by meteorological data from ARPEGE, the operational numerical weather prediction model available at the Meteo-France operation center. The overall evaluation of the results show that the model can reproduce the cloud displacement, but there exists a stretching in the transport direction. In the ATMES-II phase, the results are closer to the observations when meteorological data from the European Center for Medium range Weather Forecast are used. A simulation using analyzed meteorological data from ARPEGE every 6 h slightly improve the results comparing with the real-time experiment. All the simulations we performed reveal that the quality of the atmospheric transport model is strongly dependent on the quality of the driving numerical weather prediction model. 相似文献
503.
Atmospheric stability is the most important parameter affecting dilution of air pollutants. It plays a very important role in the investigation of parameters that affect ambient pollutant concentrations, especially in the case of complex terrain areas. In this study, the classification of atmospheric stability by Pasquill-Turner classes and any associated variation of ambient PM10 (particles with aerodynamic diameter<10 microm) concentrations for a region of complex terrain is investigated. Real experimental meteorological and PM10 data are used for a 2-year period from one observation station far distant from the main stack sources and they are related with the classified atmospheric stability categories in an hourly and monthly based distribution. A more detailed analysis is carried out during PM10 episodes for the same period in order to reveal the governing worst-case atmospheric conditions. 相似文献
504.
为探究地下公共建筑能见度降低场景中,个体及小群体楼梯上行疏散特征,在某公共建筑楼梯间进行个体疏散和小群体疏散实验,分析不同能见度条件下个体在梯段及平台上的疏散速度、疏散行为、小群体特征等关键参数。研究结果表明:梯段速度受能见度影响程度大于平台速度,在正常能见度条件下,小群体行为会对疏散移动速度产生负面影响,在低能见度条件下,小群体行为有助于提升疏散效率,表现在小群体平均速度高于群体中最慢个体速度且小群体和个体之间的速度差异较小。 相似文献
505.
In the period between 1999 and 2000 epiphytic bryophytes were taken as bioindicators for air pollution by use of the IAP method
(Index of Atmospheric Purity) and the VDI method within the Association of Engineers standards list (adapted from guideline
3799, 1995) in the heavy industrialized town of Linz, Austria. 52 study sites (265 trees) were analysed regarding species
richness, coverage, and vitality. Q-values (sensitivity factors), calculated for each species showed significant differences
for the various host tree species. The results gained by the IAP and the VDI methods were diverse, regarding the various sites
where only 25% were classified identical. These differences can mainly be attributed to the differing host tree species and
the size of the recording area on the various trees. Clusters of similar pollution levels were calculated and drawn as maps
for both methods tested. Comparing the results of the IAP and the VDI methods with data derived from technical measurements
(SO2, NO, NO2, and dust) a correlation between IAP-indices and SO2 concentrations could be observed. No correlation was detected between the results derived from VDI recording and for NO,
NO2, and dust. 相似文献
506.
507.
K. Treier K. Pajuste J. Frey 《Atmospheric environment (Oxford, England : 1994)》2004,38(40):7009-7019
Monthly and annual means of main anions (SO42−, NO3−, Cl−) and summed base cations (Ca2+, Mg2+, K+, Na+) in bulk precipitation were studied at 10 stations during an 8-year monitoring period. The data showed statistically significant decreasing trends in most cases. Average declines of mean annual volume-weighted concentrations for both anions and cations were about two-fold. Despite the decrease, the loads of S and cations are still relatively high in Estonia (about 4–14 kg S ha−1 and 0.6–1.2 keq ha−1, respectively) compared with the loads in Finland and Sweden. Estimated linear decline trends followed the same pattern as annually combusted oil shale from Estonian power plants and emissions of SO2 and fly ash. Recent trends in chemical composition of bulk precipitation at the monitoring stations reflected economic changes in Estonia as well as transboundary fluxes from neighbouring countries. 相似文献
508.
The gas phase atmospheric degradation of diazinon has been investigated at the large outdoor European Photoreactor (EUPHORE) in Valencia, Spain. The rate constant for reaction of diazinon with OH radicals was measured using a conventional relative rate method with di-n-buthylether as reference compound being k = (3.5 ± 1.2) × 10−11 cm3 molecule−1 s−1 at 302 ± 10 K and atmospheric pressure. The available evidence indicates that tropospheric degradation of diazinon is mainly controlled by reaction with OH radicals, and that the tropospheric lifetime with respect to the OH reaction is estimated to be around 4 h whereas its lifetime with respect to the photolysis is higher than 1 d under our conditions. Significant aerosol formation was observed following the reaction of diazinon with OH radicals, and the main carbon-containing products detected in the particle phase were hydroxydiazinon, hydroxydiazoxon and 2-isopropyl-6-methyl-pyrimidinyl-4-ol. 相似文献
509.
Xiao HY Wu LH Zhu RG Wang YL Liu CQ 《Environmental pollution (Barking, Essex : 1987)》2011,159(2):363-367
Nitrogen isotopic composition of new, middle-aged and old camphor leaves in upper and lower canopies has been determined in a living area, near a motorway and near an industrial area (Jiangan Chemical Fertilizer Plant). We found that at sites near roads, more positive δ15N values were observed in the camphor leaves, especially in old leaves of upper canopies, and ?δ15N = δ15Nupper − δ15Nlower > 0, while those near the industrial area had more negative δ15N values and ?δ15N < 0. These could be explained by two isotopically different atmospheric N sources: greater uptake from isotopically heavy pools of atmospheric NOx by old leaves in upper canopies at sites adjacent to roads, and greater uptake of 15N-depleted NHy in atmospheric deposition by leaves at sites near the industrial area. This study presents novel evidence that 15N natural abundance of camphor leaves can be used as a robust indicator of atmospheric N sources. 相似文献
510.
Atmospheric nitrogen deposition: revisiting the question of the importance of the organic component 总被引:2,自引:0,他引:2
Cornell SE 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2214-2222
The organic component of atmospheric reactive nitrogen plays a role in biogeochemical cycles, climate and ecosystems. Although its deposition has long been known to be quantitatively significant, it is not routinely assessed in deposition studies and monitoring programmes. Excluding this fraction, typically 25-35%, introduces significant uncertainty in the determination of nitrogen deposition, with implications for the critical loads approach. The last decade of rainwater studies substantially expands the worldwide dataset, giving enough global coverage for specific hypotheses to be considered about the distribution, composition, sources and effects of organic-nitrogen deposition. This data collation and meta-analysis highlights knowledge gaps, suggesting where data-gathering efforts and process studies should be focused. New analytical techniques allow long-standing conjectures about the nature and sources of organic N to be investigated, with tantalising indications of the interplay between natural and anthropogenic sources, and between the nitrogen and carbon cycles. 相似文献