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   120篇
  免费   7篇
  国内免费   1篇
安全科学   4篇
废物处理   4篇
环保管理   37篇
综合类   3篇
基础理论   36篇
污染及防治   22篇
评价与监测   11篇
社会与环境   11篇
  2023年   1篇
  2022年   2篇
  2021年   2篇
  2020年   2篇
  2019年   4篇
  2018年   3篇
  2017年   2篇
  2016年   8篇
  2015年   3篇
  2014年   5篇
  2013年   5篇
  2012年   5篇
  2011年   9篇
  2010年   7篇
  2009年   8篇
  2008年   16篇
  2007年   11篇
  2006年   9篇
  2005年   8篇
  2004年   1篇
  2003年   2篇
  2002年   2篇
  2001年   1篇
  1999年   3篇
  1998年   1篇
  1997年   2篇
  1994年   3篇
  1993年   1篇
  1990年   1篇
  1988年   1篇
排序方式: 共有128条查询结果,搜索用时 593 毫秒
51.
Over 400tons of Pb enters Swiss soils annually at some 2000 military shooting ranges (MSRs). We measured elements in the leaves of 10 plant species and associated rhizospheric soil on the stop butt of a disused MSR. The geometric mean concentrations of Pb, Sb, Cu, Ni in rhizospheric soils were 10,171mg/kg, 5067mg/kg, 4125mg/kg and 917mg/kg. Some species contained Pb, Cu and Ni, above concentrations (30mg/kg, 25mg/kg and 50mg/kg) shown to be toxic to livestock. Most contaminants in leaves resulted from surface deposition. However, at soil Pb concentrations >60,000mg/kg, Equisetum arvense and Tussilago farfara took up >1000mg/kg Pb into the leaves. These plants are not hyperaccumulators, having <100mg/kg Pb in leaves at lower soil concentrations. Removal of soil with more than 30,000 Pb, from which one could smelt this metal to offset remediation costs, followed by revegetation, would minimise dust and hence leaf-borne contaminants.  相似文献   
52.
The mining industry can be critical to a nation's economic well-being. Impacts may be felt on a national or regional level, with their significance dependent in part on the resources under development as well as existing government policies. This paper examines typical economic consequences of mining and how such impacts are being felt in the so-called transitional economies of Asia and Europe. Clearly, while mining continues to play an important role in the economies of Russia, China, Vietnam and other transitional nations, the nature and impacts of mining are different by virtue of years of centralized planning in the industry and the use of non-economic measures of efficiency. The changing character of mining is today opening up new opportunities for foreign investment and technology assistance.  相似文献   
53.
Private landowners in East Texas, USA, were aggregated into one of four policy categories according to the degree of access allowed to their lands for hunting. Based on these categories, a logistic regression model of possible determinants of access policy was developed and probabilities of policy adoption were calculated. Overwhelmingly, attitudes toward hunting as a sport, incentives, and control over the actions of hunters were most predictive of landowners' policies. Additionally, the availability of deer was found to be negatively correlated with access, thereby suggesting management efforts to increase deer populations may be counter to increasing access. Further, probabilities derived from the model indicated that there was almost a 7 in 10 chance (0.66) that landowners would adopt policies commensurate with allowing family and personal acquaintances to hunt on their property. However, the probability of increasing access beyond this level, where access was provided for the general public, dropped off drastically to less than 5% (0.04).  相似文献   
54.
Elevated atmospheric NH3 levels near intensive livestock operations can add significant N to local agroecosystems. In this study, the potential atmospheric NH3 sorbed by soil and water was assessed over a 2-year period starting October 2000 in an intensive livestock production area in southern Alberta, Canada. Fifty-two uneven grid sampling sites were selected in the 53,905 ha study area. The sorption rate of atmospheric NH3 was estimated weekly by exposing distilled water and air-dried soil samples to the atmosphere at the sampling sites. The increases in NH4–N content in the samples after 1-week exposure was regarded as an index of the atmospheric NH3 sorbed for that week. The NH3 sorption rates were highly variable across the 52 sites, with water ranging from 4 to 125 kg ha−1 year−1 with a mean of 22 kg N ha−1 year−1 and soil from 5 to 84 kg N ha−1 year−1 with a mean of 20 kg N ha−1 year−1. Considerable variation in NH3–N sorption across the study area reflects the effects of size, direction (upwind or downwind) and proximity of nearby livestock operations or other NH3 sources and operators’ activities around the sampling sites. The NH3 sorption rate at each site also varied considerably in response to weather conditions. The high rate of NH3 input poses a direct risk of surface water eutrophication in intensive livestock operation areas. If fertilizer recommendations are not reduced to account for NH3 sorption by soil, excess N may also contribute to eutrophication through runoff and leaching.  相似文献   
55.
Valuing water quality in China: purpose, approach and policy   总被引:12,自引:0,他引:12  
1 Introduction:heavygrowthandlightregulation(theTVIEsector)InChina,asinmanyrapidlydevelopingcountries,therearerapidchangesintheenvironmentoccurring.ThecaseofwaterqualityisanimportantoneasChina○swaterqualityhasdeterioratedsignificantlysince1980underth…  相似文献   
56.
Sea-level rise involves increases in the coastal processes of inundation and erosion which are affected by a complex interplay of physical environmental parameters at the coast. Many assessments of coastal vulnerability to sea-level rise have been detailed and localised in extent. There is a need for regional assessment techniques which identify areas vulnerable to sea-level rise. Four physical environmental parameters – elevation, exposure, aspect and slope, are modeled on a regional scale for the Northern Spencer Gulf (NSG) study area using commonly available low-resolution elevation data of 10 m contour interval and GIS-based spatial modeling techniques. For comparison, the same parameters are modeled on a fine-scale for the False Bay area within the NSG using high-resolution elevation data. Physical environmental parameters on the two scales are statistically compared to coastal vulnerability classes as identified by Harvey et al. [1] using the Spearman rank-correlation test and stepwise linear regression. Coastal vulnerability is strongly correlated with elevation and exposure at both scales and this relationship is only slightly stronger for the high resolution False Bay data. The results of this study suggest that regional scale distributed coastal process modeling may be suitable as a first cut in assessing coastal vulnerability to sea-level rise in tide-dominated, sedimentary coastal regions. Distributed coastal process modeling provides a suitable basis for the assessment of coastal vulnerability to sea-level rise of sufficient accuracy for on-ground management and priority-setting on a regional scale.  相似文献   
57.
We compared root responses of the Ni-hyperaccumulator plant Berkheya coddii Rossler with the non-accumulator plant Cicer arietinum L. to Ni heterogeneity in soil. We grew plants in growth containers filled with control soil, homogeneously spiked, and heterogeneously spiked soil with Ni concentrations of 62 and 125 mg kg?1. Neutron radiography (NR) was used to observe the root distribution and the obtained images were analysed to reveal the root volumes in the spiked and unspiked segments of the growth container. There was no significant difference in root distribution pattern of B. coddii among different concentrations of Ni. Unlike B. coddii, the roots of C. arietinum initially grew into the spiked segments. However, the later developing roots did not penetrate the spiked segment suggesting an avoidance strategy. Our results indicate that, B. coddii does not forage towards the Ni-rich patches, although presence of Ni in soil changes its root morphology.  相似文献   
58.
Mainstreaming represents an integrated, cross government agency approach to incorporating an issue into programmes and policies. Mainstreaming of resource efficiency and sustainable consumption and production (SCP and RE) has been identified to be essential to ensuring the development of policies, programmes, actions and initiatives with a wider reaching set of outcomes than if these were to be undertaken on their own. This paper outlines a guidance framework which was developed to support practitioners, champions and UN support teams on mainstreaming of SCP and RE. The framework is based on the programmatic approach to environmental mainstreaming which has been developed through wide-ranging experience on other environment and poverty-environment related topics. The approach presented here is not linear, and each of the elements requires ongoing evaluation and updating. In addition, it is identified that mainstreaming of SCP and RE should form part of overall environmental mainstreaming efforts. Furthermore, unless a country has already developed a national SCP programme, the development of such a programme and the mainstreaming process discussed in this current document should be done in parallel, not as separate processes.  相似文献   
59.
60.
Understanding perceptions of global environmental issues, such as climate change, can help inform resource management, policy development, and communication with constituents. Although a considerable amount of research documents citizens’ perceptions of climate change, few have investigated how interactions with climate-impacted parks and protected areas influence these perceptions, and consequently elements of environmental management. Using a mixed methods Instrument Development Approach, the researchers examined the stability of park visitors’ (N = 429) climate change perceptions during a daylong interaction with climate-sensitive and influenced resources at Kenai Fjords National Park in Alaska. Results indicate that global-level beliefs about climate change remained relatively stable during a park experience, but perceptions about climate change at the park-level (e.g., impacts) appeared more malleable. Findings also revealed the type of park experience (terrestrial vs. marine) can influence the degree of change in visitors’ perceptions. Implications for communication, outreach, and park management are discussed.  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