全文获取类型
收费全文 | 1203篇 |
免费 | 20篇 |
国内免费 | 11篇 |
专业分类
安全科学 | 68篇 |
废物处理 | 75篇 |
环保管理 | 292篇 |
综合类 | 126篇 |
基础理论 | 221篇 |
环境理论 | 2篇 |
污染及防治 | 296篇 |
评价与监测 | 98篇 |
社会与环境 | 39篇 |
灾害及防治 | 17篇 |
出版年
2023年 | 9篇 |
2022年 | 7篇 |
2021年 | 9篇 |
2020年 | 16篇 |
2019年 | 16篇 |
2018年 | 20篇 |
2017年 | 18篇 |
2016年 | 22篇 |
2015年 | 20篇 |
2014年 | 26篇 |
2013年 | 134篇 |
2012年 | 40篇 |
2011年 | 56篇 |
2010年 | 53篇 |
2009年 | 50篇 |
2008年 | 59篇 |
2007年 | 66篇 |
2006年 | 68篇 |
2005年 | 48篇 |
2004年 | 33篇 |
2003年 | 53篇 |
2002年 | 46篇 |
2001年 | 19篇 |
2000年 | 14篇 |
1999年 | 19篇 |
1998年 | 21篇 |
1997年 | 10篇 |
1996年 | 11篇 |
1995年 | 23篇 |
1994年 | 12篇 |
1993年 | 10篇 |
1992年 | 15篇 |
1991年 | 13篇 |
1990年 | 17篇 |
1989年 | 13篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 8篇 |
1985年 | 15篇 |
1984年 | 11篇 |
1983年 | 14篇 |
1982年 | 19篇 |
1981年 | 24篇 |
1980年 | 10篇 |
1979年 | 13篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 8篇 |
1972年 | 4篇 |
1971年 | 4篇 |
排序方式: 共有1234条查询结果,搜索用时 679 毫秒
371.
Canagaratna MR Onasch TB Wood EC Herndon SC Jayne JT Cross ES Miake-Lye RC Kolb CE Worsnop DR 《Journal of the Air & Waste Management Association (1995)》2010,60(10):1192-1203
Aerosol mass spectrometer (AMS) measurements are used to characterize the evolution of exhaust particulate matter (PM) properties near and downwind of vehicle sources. The AMS provides time-resolved chemically speciated mass loadings and mass-weighted size distributions of nonrefractory PM smaller than 1 microm (NRPM1). Source measurements of aircraft PM show that black carbon particles inhibit nucleation by serving as condensation sinks for the volatile and semi-volatile exhaust gases. Real-world source measurements of ground vehicle PM are obtained by deploying an AMS aboard a mobile laboratory. Characteristic features of the exhaust PM chemical composition and size distribution are discussed. PM mass and number concentrations are used with above-background gas-phase carbon dioxide (CO2) concentrations to calculate on-road emission factors for individual vehicles. Highly variable ratios between particle number and mass concentrations are observed for individual vehicles. NRPM1 mass emission factors measured for on-road diesel vehicles are approximately 50% lower than those from dynamometer studies. Factor analysis of AMS data (FA-AMS) is applied for the first time to map variations in exhaust PM mass downwind of a highway. In this study, above-background vehicle PM concentrations are highest close to the highway and decrease by a factor of 2 by 200 m away from the highway. Comparison with the gas-phase CO2 concentrations indicates that these vehicle PM mass gradients are largely driven by dilution. Secondary aerosol species do not show a similar gradient in absolute mass concentrations; thus, their relative contribution to total ambient PM mass concentrations increases as a function of distance from the highway. FA-AMS of single particle and ensemble data at an urban receptor site shows that condensation of these secondary aerosol species onto vehicle exhaust particles results in spatial and temporal evolution of the size and composition of vehicle exhaust PM on urban and regional scales. 相似文献
372.
Sheng-Chieh Chen Chuen-Jinn Tsai Charles C.-K. Chou Gwo-Dong Roam Sen-Sung Cheng Ya-Nan Wang 《Atmospheric environment (Oxford, England : 1994)》2010,44(4):533-540
Atmospheric ultrafine particles (UPs or PM0.1) were investigated at the roadside of Syuefu road in Hsinchu city, in the Syueshan highway tunnel in Taipei and in the NTU Experimental Forest in Nantou, Taiwan. A SMPS (TSI 3936) and three MOUDIs (MSP 110) were collocated to determine the number and mass concentrations of the PM0.1 simultaneously. The filter samples were further analyzed for organic carbon (OC), element carbon (EC), water-soluble ions and trace elements. Taking into account the OC artifact of PM0.1, good chemical mass closure (ratio of the reconstructed chemical mass to the gravimetrical mass of PMs) was obtained with an unknown percentage of 10.6, 26.2 and 37.2% at the roadside, tunnel and forest, respectively. The unexplained mass was attributed to aerosol water in this study. The artifact at the roadside, tunnel and the forest PM0.1 mass was found to be as high as 51.6 ± 10.7%, 20.0 ± 5.4% and 85.6 ± 18.4%, respectively. Finally, the effective density of the roadside, tunnel and forest PM0.1 was calculated based on the results of chemical speciation and found to be 1.45, 1.29 and 1.22 g cm?3, respectively, which was in good agreement with that obtained by using the method of Spencer et al. (2007). Based on these results, it is foreseeable that the number concentration of the SMPS can be converted using the effective density determined by Spencer et al. (2007) for the real time measurement of the PM0.1 concentration. 相似文献
373.
Quick BL Stephenson MT Witte K Vaught C Booth-Butterfield S Patel D 《Journal of Safety Research》2008,39(3):329-338
PROBLEM: The National Institute for Occupational Safety and Health's [NIOSH] National Occupational Research Agenda (DHHS Publication No. 96-115) reports that approximately 50% of miners will experience hearing loss by age 50, compared to only 9% of the general population. The present investigation examines three antecedents believed to be associated with miner's use of hearing protection. METHOD: A posttest-delayed-posttest-control group field research design was employed to assess antecedents toward wearing hearing protection. RESULTS: Following the initial posttest, miners' attitudes and subjective norms were antecedents to intentions to wear hearing protection devices. Also, intentions toward wearing hearing protection predicted hearing protection behaviors. Approximately six weeks later, miners' attitudes and perceived behavioral control were each significant predictors of intentions to wear hearing protection and again, intentions were positively associated with hearing protection behaviors. IMPACT ON INDUSTRY: Our results indicate that appeals to normative influences may be the most effective antecedent to employ when persuading coal miners to wear hearing protection. However, messages designed to impact attitudes and perceived behavioral control were also effective. 相似文献
374.
Sorption of nonpolar neutral organic compounds to humic acid-coated sands: contributions of organic and mineral components 总被引:2,自引:0,他引:2
The contributions of organic matter and the mineral surface to the overall sorption of six nonpolar neutral organic compounds (1,2,4-trichlorobenzene, 1,4-dichlorobenzene, chlorobenzene, m-xylene, toluene, benzene) by five humic acid (HA)-coated sands with different fractions of organic carbon (f(oc)) ranging from 0.024% to 0.154% were evaluated on the basis of measured data and four different sorption models. Sorption of all six sorbates to both uncoated and heated sands was nearly linear due to the coverage of hydrophilic mineral surface with the ordered vicinal water region. Sorption of all six sorbates to the HA-coated sands was also essentially linear, and resulted from a combination of sorption to both organic matter and the mineral surface, with the dominance of either contribution depending on the properties of the sorbents (e.g., f(oc)) and the sorbates (e.g., K(ow)). A proposed two-component model for sorption including blocking effect was appropriate for quantifying the contributions of organic matter and the mineral surface to the overall sorption. However, conventional sorption models considering the contributions of both organic matter and the mineral surface provided essentially as good agreement between predicted and measured distribution coefficients as the more complicated, two-component model for sorption that takes into account mineral surface blocking by HA. 相似文献
375.
Changes in contaminant mass discharge from DNAPL source mass depletion: evaluation at two field sites 总被引:1,自引:0,他引:1
Brooks MC Wood AL Annable MD Hatfield K Cho J Holbert C Rao PS Enfield CG Lynch K Smith RE 《Journal of contaminant hydrology》2008,102(1-2):140-153
Changes in contaminant fluxes resulting from aggressive remediation of dense nonaqueous phase liquid (DNAPL) source zone were investigated at two sites, one at Hill Air Force Base (AFB), Utah, and the other at Ft. Lewis Military Reservation, Washington. Passive Flux Meters (PFM) and a variation of the Integral Pumping Test (IPT) were used to measure fluxes in ten wells installed along a transect down-gradient of the trichloroethylene (TCE) source zone, and perpendicular to the mean groundwater flow direction. At both sites, groundwater and contaminant fluxes were measured before and after the source-zone treatment. The measured contaminant fluxes (J; ML(-2)T(-1)) were integrated across the well transect to estimate contaminant mass discharge (M(D); MT(-1)) from the source zone. Estimated M(D) before source treatment, based on both PFM and IPT methods, were approximately 76 g/day for TCE at the Hill AFB site; and approximately 640 g/day for TCE, and approximately 206 g/day for cis-dichloroethylene (DCE) at the Ft. Lewis site. TCE flux measurements made 1 year after source treatment at the Hill AFB site decreased to approximately 5 g/day. On the other hand, increased fluxes of DCE, a degradation byproduct of TCE, in tests subsequent to remediation at the Hill AFB site suggest enhanced microbial degradation after surfactant flooding. At the Ft. Lewis site, TCE mass discharge rates subsequent to remediation decreased to approximately 3 g/day for TCE and approximately 3 g/day for DCE approximately 1.8 years after remediation. At both field sites, PFM and IPT approaches provided comparable results for contaminant mass discharge rates, and show significant reductions (>90%) in TCE mass discharge as a result of DNAPL mass depletion from the source zone. 相似文献
376.
Selvendiran P Driscoll CT Bushey JT Montesdeoca MR 《Environmental pollution (Barking, Essex : 1987)》2008,154(1):46-55
The transport and fate of mercury (Hg) was studied in two forest wetlands; a riparian peatland and an abandoned beaver meadow. The proportion of total mercury (THg) that was methyl mercury (% MeHg) increased from 2% to 6% from the upland inlets to the outlet of the wetlands. During the growing season, MeHg concentrations were approximately three times higher (0.27ng/L) than values during the non-growing season (0.10ng/L). Transport of Hg species was facilitated by DOC production as indicated by significant positive relations with THg and MeHg. Elevated concentrations of MeHg and % MeHg (as high as 70%) were found in pore waters of the riparian and beaver meadow wetlands. Groundwater interaction with the stream was limited at the riparian peatland due to the low hydraulic conductivity of the peat. The annual fluxes of THg and MeHg at the outlet of the watershed were 2.3 and 0.092microg/m2-year respectively. 相似文献
377.
Revital Bookman Charles T. Driscoll Daniel R. Engstrom Steven W. Effler 《Atmospheric environment (Oxford, England : 1994)》2008,42(24):6088-6097
Lake-sediment records across the Northern Hemisphere show increases in atmospheric deposition of anthropogenic mercury (Hg) over the last 150 years. Most of the previous studies have examined remote lakes affected by the global atmospheric Hg reservoir. In this study, we present Hg flux records from lakes in an urban/suburban setting of central New York affected also by local and regional emissions. Sediment cores were collected from the Otisco and Skaneateles lakes from the Finger Lakes region, Cross Lake, a hypereutrophic lake on the Seneca River, and Glacial Lake, a small seepage lake with a watershed that corresponds with the lake area. Sediment accumulation rates and dates were established by 210Pb. The pre-anthropogenic regional atmospheric Hg flux was estimated to be 3.0 μg m−2 yr−1 from Glacial Lake, which receives exclusively direct atmospheric deposition. Mercury fluxes peaked during 1971–2001, and were 3 to more than 30 times greater than pre-industrial deposition. Land use change and urbanization in the Otisco and Cross watersheds during the last century likely enhanced sediment loads and Hg fluxes to the lakes. Skaneateles and Glacial lakes have low sediment accumulation rates, and thus are excellent indicators for atmospheric Hg deposition. In these lakes, we found strong correlations with emission records for the Great Lakes region that markedly increased in the early 1900s, and peaked during WWII and in the early 1970s. Declines in modern Hg fluxes are generally evident in the core records. However, the decrease in sediment Hg flux at Glacial Lake was interrupted and has increased since the early 1990s probably due to the operation of new local emission sources. Assuming the global Hg reservoir tripled since the pre-industrial period, the contribution of local and regional emission sources to central New York lakes was estimated to about 80% of the total atmospheric Hg deposition. 相似文献
378.
379.
Robert Mc Morran Martin F. Price Charles R. Warren 《Journal of Environmental Planning and Management》2008,51(2):177-199
Concepts of wild land have recreational, ecological and cultural dimensions, and place varying emphasis on physical landscape attributes and the perceptions of users. In Scotland, national and NGO policies show reasonable consistency in interpreting and defining ‘wild land’, emphasising the (perception of) lack of current human influence as a key criterion. This research used semi-structured interviews with key individuals and a questionnaire survey of land managers to evaluate concepts and perceptions of wild land in Scotland. Recognising that the conceptual and spatial definition of wild land is a key issue, a new typology is proposed. Weaknesses in the policy framework, as well as key potential threats to, and opportunities associated with, wild landscapes are identified. Management initiatives are fitted to the typology and divided into four management themes. Key recommendations are: (i) that national policy for wild landscapes needs to incorporate criteria, which recognise the multiple values deriving from such areas; and (ii) that future research should combine user group preferences with physical attribute information in determining what constitutes wild landscapes. 相似文献
380.
Coupled human and natural systems 总被引:18,自引:0,他引:18
Liu J Dietz T Carpenter SR Folke C Alberti M Redman CL Schneider SH Ostrom E Pell AN Lubchenco J Taylor WW Ouyang Z Deadman P Kratz T Provencher W 《Ambio》2007,36(8):639-649
Humans have continuously interacted with natural systems, resulting in the formation and development of coupled human and natural systems (CHANS). Recent studies reveal the complexity of organizational, spatial, and temporal couplings of CHANS. These couplings have evolved from direct to more indirect interactions, from adjacent to more distant linkages, from local to global scales, and from simple to complex patterns and processes. Untangling complexities, such as reciprocal effects and emergent properties, can lead to novel scientific discoveries and is essential to developing effective policies for ecological and socioeconomic sustainability. Opportunities for truly integrating various disciplines are emerging to address fundamental questions about CHANS and meet society's unprecedented challenges. 相似文献