全文获取类型
收费全文 | 304篇 |
免费 | 12篇 |
国内免费 | 4篇 |
专业分类
安全科学 | 52篇 |
废物处理 | 7篇 |
环保管理 | 73篇 |
综合类 | 41篇 |
基础理论 | 57篇 |
污染及防治 | 68篇 |
评价与监测 | 13篇 |
社会与环境 | 6篇 |
灾害及防治 | 3篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 2篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 9篇 |
2017年 | 10篇 |
2016年 | 9篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 25篇 |
2012年 | 17篇 |
2011年 | 15篇 |
2010年 | 17篇 |
2009年 | 9篇 |
2008年 | 17篇 |
2007年 | 19篇 |
2006年 | 15篇 |
2005年 | 14篇 |
2004年 | 18篇 |
2003年 | 15篇 |
2002年 | 13篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 10篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有320条查询结果,搜索用时 500 毫秒
311.
Researchers attempting to integrate socio-economic data in watershed planning often draw on nationally collected census data. However, there are critical limitations to the usefulness of this type of data for decision makers operating at the watershed scale. In this paper we demonstrate the relevance of spatially referenced socio-economic data collected using mail surveys to random selections of rural landholders. The issue explored was dryland salinity management in two large watersheds in the Murray-Darling Basin of south-eastern Australia. Contrary to the assumptions underlying public policy in Australia, but consistent with the literature on farmer knowledge, comparisons of expert maps and landholder identified salinity sites suggested that landholders in these watersheds had excellent knowledge of the current extent of salinity on their property. Our research also suggested that salinity education was a sound investment by governments. At the same time, the expert maps failed to predict half of the saline affected sites identified by landholders. Accurately mapping the extent of salinity would seem a first step in addressing this nationally significant land degradation issue. 相似文献
312.
A graduated licensing (GL) program was introduced in Nova Scotia, Canada, in October 1994. Previous research has shown that it reduced collisions in the short term. The present study examined the relative contribution of each stage of the program (i.e., learner and intermediate levels) and the program's impact after beginning drivers graduated to full licensure. The research focused on teenage beginning drivers (age 16-17), but the effects on older beginners also was examined. Per-driver crash rates of two groups of novices selected from driver records in Nova Scotia were compared. One group (pre-GL) received their learner's permits during the 2 years before the program was implemented, and the second group (GL) received their learner's permits during the 2 years after implementation. The findings clearly establish that most of the collision reduction in Nova Scotia's program occurred during the first year of the program, particularly during the first 6 months when the majority of novices were driving under supervision. The collision rate for 16 to 17-year-old GL novices was 50% lower than the rate for pre-GL novices during the 6 months after they received their learner's permits, and about 10% lower during their first 2 years of licensure when unsupervised driving from midnight to 5 A.M. was prohibited. Much of this improvement for 16 to 17-year-olds occurred during restricted night hours. Collision rates also were lower during nonrestricted hours in the initial 6 months of licensure. The 3-month "time discount" for driver education provided no safety benefit, and GL novices with driver education had collision rates that were not lower than pre-GL novices. There was no long-term effect found for the program after 16 to 17-year-olds graduated to full licensure. For older beginning drivers, crash rates during the first year after obtaining a learner's permit showed a 31% reduction. This effect diminished rapidly. There was only a 2% reduction during the first year of licensure, and crash rates increased during the following 2 years. Overall the data indicate substantial benefits of graduated licensing for 16 to 17-year-old beginners, but no benefits beyond the learner stage for older beginners. 相似文献
313.
Assessment of potential groundwater contamination sources in a wellhead protection area 总被引:1,自引:0,他引:1
Determining the human health dangers from potential contamination sources, within a wellhead protection area (WHPA), requires that a risk analysis be undertaken. In this study, a desktop geographic information system and spreadsheet software are used to implement an EPA risk screening methodology for WHPAs called 'Managing Ground Water Contamination Sources in Wellhead Protection Areas--A Priority Setting Approach'. The methodology was applied to a WHPA in Gaston County, North Carolina. Results indicate that the risk of well contamination from an interstate highway and gas station with old steel underground storage tanks were comparatively high. Medium risks included a thoroughfare and highway, while low risks were assigned to machine shops, a body shop, septic systems and a gas station with new underground storage tanks and secondary containment. A sensitivity analyses of the Priority Setting Approach indicated that risk scores were extremely sensitive to hydrogeologic variables such as hydraulic conductivity. It is recommended that risk assessors utilize a range of hydrogeologic parameters to assess overall risk from each potential contamination source. 相似文献
314.
J. H. Allan 《Die Naturwissenschaften》1960,47(16):376-377
315.
316.
Life table evaluation of chronic exposure of Eurytemora affinis (Copepoda) to Kepone 总被引:1,自引:0,他引:1
Life table estimates of intrinsic rate of natural increase (r) were used to assess chronic toxicity of Kepone to the copepod Eurytemora affinis (Poppe). The acute toxicity (48-h LC 50) was determined to be 40g 1-1 (95% CL 33.9–47.2). A reduction in r was observed at all concentrations above 5 g 1-1, and r was near zero at 20 g 1-1. This was due to the combination of lowered survivorship, delayed onset of reproduction and reduced fecundity. We discuss the value of the life table approach both as an experimental protocol and an ecologically realistic bioassay of chronic effects, and document that as few as 21 d are sufficient as an adequate test duration. 相似文献
317.
/ Regional resource use planning relies on key regional stakeholder groups using and having equitable access to appropriate social, economic, and environmental information and assessment tools. Decision support systems (DSS) can improve stakeholder access to such information and analysis tools. Regional resource use planning, however, is a complex process involving multiple issues, multiple assessment criteria, multiple stakeholders, and multiple values. There is a need for an approach to DSS development that can assist in understanding and modeling complex problem situations in regional resource use so that areas where DSSs could provide effective support can be identified, and the user requirements can be well established. This paper presents an approach based on the soft systems methodology for identifying DSS opportunities for regional resource use planning, taking the Central Highlands Region of Queensland, Australia, as a case study. 相似文献
318.
Bottom sediment and suspended sediment samples from Hamilton Harbour (western Lake Ontario) and from a major tributary were profiled using polycyclic aromatic hydrocarbons (PAH) and thia-arenes as source apportionment tracers. Ratios of selected PAH and ratios of monomethyl and dimethyl/ethyl dibenzothiophenes to the parent dibenzothiophenes were calculated. Thia-arene and PAH profiles of Standard Reference Material SRM 1649 (urban dust/organics), SRM 1650 (diesel), SRM 1597 (coal tar), Hamilton coal tar and a composite Hamilton air particulate sample provided source sample data. The gas chromatography-mass spectrometry (GC-MS) chromatograms of all sample extracts were dominated by homocyclic PAH but interpretation of PAH profiles with respect to source was difficult. In contrast, thia-arene analyses revealed more distinct differences in profiles of samples collected in different areas of the harbour, including the tributary. These results indicated that areas of coal tar-contaminated sediment are potential contributors to the overall contaminant burden of sediments and suspended sediments in Hamilton Harbour. These data also indicated that contaminants related to mobile combustion sources were entering the harbour via a major tributary. 相似文献
319.
Hydrology, roadway traffic conditions, and atmospheric deposition are three essential data categories for the planning and
implementation of highway-runoff monitoring and characterization programs. Causal variables pertaining to each data category
could be site specific but have been shown to correlate with runoff pollutant loads. These data categories were combined to
derive statistical relationships for characterization and prioritization of the respective pollutant loads at highway runoff
sites. Storm runoff data of total suspended solids (TSS), total dissolved solid (TDS), chemical oxygen demand (COD), total
Kjeldahl nitrogen (TKN) and total phosphorus (TP) collected from three highway sites in Charlotte, North Carolina, USA, were
used to illustrate the development of site-specific highway-runoff pollutant loading models. This unified methodology provides
a basis for initial assessment of the pollutant-constituent loads from highway runoff using hydrologic component variables.
Improved reliability is achievable when additional traffic and/or atmospheric component variables are incorporated into the
basic hydrologic regression model. In addition, operational guidance is suggested for implementing highway-runoff monitoring
programs that are subject to sampling and resources constraints. 相似文献
320.
Davis Lodinikki Lemoy Aragão Walessa Alana Bragança de Oliveira Lopes Géssica Eiró Luciana Guimaraes Freire Alexandre Rodrigues Prado Felippe Bevilacqua Rossi Ana Cláudia da Silva Cruz Allan das Graças Fernandes Dantas Kelly Albuquerque Alan Rodrigo Leal Paz Simone Patricia Aranha Angélica Rômulo Simões Lima Rafael Rodrigues 《Environmental science and pollution research international》2022,29(10):13930-13940
Environmental Science and Pollution Research - There are a few data relating to the effects of lead (Pb) exposure on the alveolar bone, which has very distinct morphophysiological characteristics... 相似文献