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   280篇
  免费   6篇
安全科学   13篇
废物处理   16篇
环保管理   59篇
综合类   37篇
基础理论   72篇
污染及防治   50篇
评价与监测   27篇
社会与环境   8篇
灾害及防治   4篇
  2023年   3篇
  2022年   6篇
  2021年   2篇
  2020年   3篇
  2019年   3篇
  2018年   4篇
  2017年   8篇
  2016年   8篇
  2015年   10篇
  2014年   14篇
  2013年   20篇
  2012年   10篇
  2011年   22篇
  2010年   6篇
  2009年   10篇
  2008年   17篇
  2007年   13篇
  2006年   9篇
  2005年   10篇
  2004年   4篇
  2003年   8篇
  2002年   11篇
  2001年   5篇
  2000年   6篇
  1999年   8篇
  1997年   5篇
  1996年   4篇
  1995年   4篇
  1994年   4篇
  1993年   4篇
  1992年   4篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1986年   3篇
  1985年   6篇
  1984年   4篇
  1983年   3篇
  1982年   6篇
  1981年   3篇
  1980年   4篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1975年   1篇
  1970年   1篇
  1959年   1篇
排序方式: 共有286条查询结果,搜索用时 265 毫秒
91.

This paper provides an assessment of the tools required to fulfil the air quality management role now expected of local authorities within the UK. The use of a range of pollution monitoring tools in assessing air quality is discussed and illustrated with evidence from a number of previous studies of urban background and roadside pollution monitoring in Leicester. A number of approaches to pollution modelling currently available for deployment are examined. Subsequently, the modelling and monitoring tools are assessed against the requirements of local authorities establishing air quality management areas. Whilst the paper examines UK-based policy, the study is of wider international interest.  相似文献   
92.
Studies in Europe have reported negative effects of acid deposition on forest birds, and research in North America has identified links between forest bird abundance and rates of acid deposition. We examined the bird community in an acidified forest in central Pennsylvania (USA) and evaluated the effects of terrestrial lime application on birds. We used a before-after control-impact (BACI) study design, with one year of observation before (2003) and three years after lime application (2004, 2005, and 2006). Between the 2003 and 2004 field seasons, 4500 kg/ha of dolomitic lime were applied to two of four 100-ha watersheds. Each year, we monitored bird abundance and Ovenbird (Seiurus aurocapilla) eggshell thickness and territory size. Soil and snail abundance data were also collected. The bird community and territory size results indicated that the study area may be providing low-quality habitat for forest birds, perhaps as a result of acid deposition. We found lower forest bird abundances than have been found in less acidified areas of Pennsylvania, and larger Ovenbird territory sizes than have been found in other studies. We found a significant positive relationship between soil calcium and bird abundance, indicating that soil calcium may affect bird abundance. Liming increased soil calcium and pH and led to increased snail and bird abundances. After liming, bird abundance was positively related to snail abundance. No significant changes occurred in Ovenbird territory size or eggshell thickness. Our results suggest that acid deposition could be responsible for reduced bird abundance, and that liming is a potential mitigation technique.  相似文献   
93.
A comprehensive synthesis of data from empirically based published studies and a widely used stormwater best management practice (BMP) database were used to assess the variability in nitrogen (N) removal performance of urban stormwater ponds, wetlands, and swales and to identify factors that may explain this variability. While the data suggest that BMPs were generally effective on average, removal efficiencies of ammonium (NH4), nitrate (NO3), and total nitrogen (TN) were highly variable ranging from negative (i.e., BMPs acting as sources of N) to 100%. For example, removal of NO3 varied from (median ±1 SD) ?15 ± 49% for dry ponds, 32 ± 120% for wet ponds, 58 ± 210% for wetlands, and 37 ± 29% for swales. Across the same BMP types, TN removal was 27 ± 24%, 40 ± 31%, 61 ± 30%, and 50 ± 29%. NH4 removal was 9 ± 36%, 29 ± 72%, 31 ± 24%, and 45 ± 34%. BMP size, age, and location explained some of the variability. For example, small and shallow ponds and wetlands were more effective than larger, deeper ones in removing N. Despite well‐known intra‐annual variation in N fluxes, most measurements have been made over short time periods using concentrations, not flow‐weighted N fluxes. Urban N export is increasing in some areas as large storms become more frequent. Thus, accounting for the full range of BMP performance under such conditions is crucial. A select number of long‐term flux‐based BMP studies that rigorously measure rainfall, hydrology, and site conditions could improve BMP implementation.  相似文献   
94.
Key biological processes such as the timing and synchrony of reproduction, are sensitive to fluctuations in the environment, as well as alterations in the physiology and behaviour of individuals and the ecology of populations. The main aim of this study was to identify patterns in reproductive timing and relationships with prevailing environmental conditions, for the major habitat-forming alga in temperate Australia, Ecklonia radiata (C. Agardh) J. Agardh. We observed strong synchronous patterns of zoospore production across spatial scales from hundreds of metres to tens of kilometres, with populations of E. radiata reproducing from mid-summer to the end of autumn. High zoospore densities were positively related to sea temperature and E. radiata released zoospores in temperatures well above previously documented thermal tolerance limits for other Laminariales. Reproductive timing was also negatively related to seasonal increase in wave exposure. We conclude that E. radiata undergoes synchronous reproduction which can be linked to its annual growth cycle and natural environmental fluctuations, to promote growth and survival of recruits.  相似文献   
95.
Diasporas and diaspora non‐governmental organisations (NGOs) are increasingly important as resource lifelines to their home countries, yet the resources that they mobilise, the types of challenges that they face, and their coping mechanisms are not well explored or understood in the context of disaster recovery. To fill this knowledge gap, this study employed an inductive qualitative methodological approach, using interviews to comprehend the role played by Haitian diaspora NGOs after the catastrophic earthquake in 2010. It found that resources take four common forms: event fundraisers; financial and material donations from supporters; remittances; and volunteer labour. Challenges include an overreliance on diaspora donors, competition among NGOs, and what is perceived as inequitable funding practices towards diaspora NGOs. The findings provide insights centred on better coordination among diaspora NGOs, as well as between diaspora NGOs and other local and international NGOs and local governments and international institutions, to ensure more efficient delivery of services to survivors.  相似文献   
96.
97.
98.
Since 1987, the Alaska Marine Mammal Tissue Archival Project (AMMTAP) has collected tissues from 18 marine mammal species. Specimens are archived in the National Institute of Standards and Technology's National Biomonitoring Specimen Bank (NIST-NBSB). AMMTAP has collected blubber, liver and/or kidney specimens from a number of ringed seals (Phoca hispida) from the areas near Nome and Barrow, Alaska and walruses (Odobenus rosmarus) from several locations in the Bering Sea. Thirty-three ringed seal and 15 walrus blubber samples from the NIST-NBSB were analyzed for persistent organic pollutants (POPs). The compounds determined included PCBs (28 congeners or congener groups), DDT and related compounds, hexachlorobenzene (HCB), hexachlorocyclohexane isomers (HCHs), chlordanes, dieldrin, and mirex. POP concentrations in ringed seal blubber were significantly higher in Barrow than in Nome when statistically accounting for the interaction of age and gender; HCB, however, was not statistically different between the two locations. Unlike males, POP concentrations and age were not significantly correlated in females probably as a result of lactational loss. POP concentrations in walrus blubber were lower than in ringed seal blubber for SigmaPCBs, chlordanes, and HCHs, but higher for dieldrin and mirex. POP concentrations in ringed seals and walrus from Alaska provide further evidence that the western Arctic tends to have lower or similar POP concentrations compared to the eastern Canadian Arctic.  相似文献   
99.
Environmental Management - This paper investigates the influence of using indigenous forecasts (IF) and scientific forecasts (SF) on arable farmers’ adaptation methods in the Rwenzori region,...  相似文献   
100.
Like many small-scale fishing communities around the world, the community of Buen Hombre in the Dominican Republic is dealing with a set of challenges to reconcile its fishing activities with the ecology on which it depends. Also like many such communities, this case has been examined at a particular period in time by a group of social scientists, but not over substantial lengths of time in order to examine the longitudinal validity of the conclusions made during this period. In this paper we combine data from previous anthropological work with our own primary social and ecological data to conduct a longitudinal case study of the Buen Hombre fishery. Our over-time comparison focuses on a suite of mostly social and institutional variables to explain what we find to be a continued degradation of the fishery, and we conclude the analysis by presenting a causal-loop diagram, summarizing our inferences regarding the complex interactions among these variables. We find that a mix of factors, notably changes in gear and fishing sites used, the number of fishermen and their livelihood diversity, as well as an increased connectivity between Buen Hombre and its external environment, have contributed to the decline of the condition of Buen Hombre coral reef fishery. We conclude with a discussion of what may lie ahead for this particular case and others like it.  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