全文获取类型
收费全文 | 206篇 |
免费 | 16篇 |
国内免费 | 4篇 |
专业分类
安全科学 | 7篇 |
废物处理 | 3篇 |
环保管理 | 39篇 |
综合类 | 37篇 |
基础理论 | 80篇 |
环境理论 | 3篇 |
污染及防治 | 30篇 |
评价与监测 | 13篇 |
社会与环境 | 10篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 8篇 |
2021年 | 6篇 |
2020年 | 7篇 |
2019年 | 12篇 |
2018年 | 11篇 |
2017年 | 17篇 |
2016年 | 21篇 |
2015年 | 13篇 |
2014年 | 9篇 |
2013年 | 17篇 |
2012年 | 13篇 |
2011年 | 15篇 |
2010年 | 7篇 |
2009年 | 9篇 |
2008年 | 15篇 |
2007年 | 11篇 |
2006年 | 11篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1998年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有226条查询结果,搜索用时 109 毫秒
191.
Emily Mann Michael A. Long Paul B. Stretesky Margaret Anne Defeyter 《Local Environment》2018,23(10):1008-1022
In response to the problem of holiday hunger, hundreds of local “holiday clubs” have recently been established across the UK. This research examines the spatial relationship between income, childhood deprivation, ethnicity and holiday clubs across 32,844 Lower Super Output Areas (LSOAs) in England to determine if these clubs are currently operating in an inclusive fashion. Data on the location of holiday clubs comes from a national survey. Binary logistic regression results suggest that holiday clubs are likely to operate in economically disadvantaged areas. At the same time, clubs are not distributed equally by ethnicity. That is, holiday clubs operated by voluntary organisations are more likely to be situated in LSOAs that are disproportionately white and English\British and less likely to be situated in LSOAs that are disproportionately ethnic minority. This finding has important implications for the pursuit of holiday clubs as a policy mechanism for addressing access to food in light of the state’s failure to adequately feed all of the country’s children. 相似文献
192.
Emily Jane Davis Lauren Gwin Cassandra Moseley Hannah Gosnell Harmony Burright 《Journal of Environmental Planning and Management》2015,58(9):1562-1576
Payments for ecosystem or ecological services (PES) are voluntary, often market-based approaches to protecting environmental values. In the rural United States, some landowners receive PES through government led conservation programs, but little is known about their involvement in market based arrangements. We analyzed three examples of market based PES arrangements in northwestern Montana: watershed restoration and craft brewing, niche meat production, and certified timber supplies. We find that intermediaries were working between buyers and sellers in each case to set conditions for transactions and undertake the mechanics of implementation. These findings align with existing conceptualizations of intermediaries as crucial links in PES arrangements, but also suggest that intermediaries for market based PES arrangements are not always facilitators or neutral nongovernmental actors; they may actually be from the private sector and drive the process by serving as buyers. This research contributes to stronger understanding of the possibilities for local market based conservation in the rural West. 相似文献
193.
194.
Evaluation of organic contamination in urban groundwater surrounding a municipal landfill, Zhoukou, China 总被引:1,自引:0,他引:1
D. M. Han X. X. Tong M. G. Jin Emily Hepburn C. S. Tong X. F. Song 《Environmental monitoring and assessment》2013,185(4):3413-3444
This paper investigates the organic pollution status of shallow aquifer sediments and groundwater around Zhoukou landfill. Chlorinated aliphatic hydrocarbons, monocylic aromatic hydrocarbons, halogenated aromatic hydrocarbons, organochlorine pesticides and other pesticides, and polycyclic aromatic hydrocarbons (PAHs) have been detected in some water samples. Among the detected eleven PAHs, phenanthrene, fluorine, and fluoranthene are the three dominant in most of the groundwater samples. Analysis of groundwater samples around the landfill revealed concentrations of PAHs ranging from not detected to 2.19 μg/L. The results show that sediments below the waste dump were low in pollution, and the shallow aquifer, at a depth of 18–30 m, was heavily contaminated, particularly during the wet season. An oval-shaped pollution halo has formed, spanning 3 km from west to east and 2 km from south to north, and mainly occurs in groundwater depths of 2–4 m. For PAH source identification, both diagnostic ratios of selected PAHs and principal component analysis were studied, suggesting mixed sources of pyro- and petrogenic derived PAHs in the Zhoukou landfill. Groundwater table fluctuations play an important role in the distribution of organic pollutants within the shallow aquifer. A conceptual model of leachate migration in the Quaternary aquifers surrounding the Zhoukou landfill has been developed to describe the contamination processes based on the major contaminant (PAHs). The groundwater zone contaminated by leachate has been identified surrounding the landfill. 相似文献
195.
Pouliot G Wisner E Mobley D Hunt W 《Journal of the Air & Waste Management Association (1995)》2012,62(3):287-298
Emissions factors are important for estimating and characterizing emissions from sources of air pollution. There is no quantitative indication of uncertainty for these emission factors, most factors do not have an adequate data set to compute uncertainty, and it is very difficult to locate the data for those that do. The objectives are to compare the current emission factors of Electric Generating Unit NOx sources with currently available continuous emission monitoring data, develop quantitative uncertainty indicators for the Environmental Protection Agency (EPA) data quality rated emission factors, and determine the possible ranges of uncertainty associated with EPA's data quality rating of emission factors. EPA's data letter rating represents a general indication of the robustness of the emission factor and is assigned based on the estimated reliability of the tests used to develop the factor and on the quantity and representativeness of the data. Different sources and pollutants that have the same robustness in the measured emission factor and in the representativeness of the measured values are assumed to have a similar quantifiable uncertainty. For the purposes of comparison, we assume that the emission factor estimates from source categories with the same letter rating have enough robustness and consistency that we can quantify the uncertainty of these common emission factors based on the qualitative indication of data quality which is known for almost all factors. The results showed that EPA's current emission factor values for NOx emissions from combustion sources were found to be reasonably representative for some sources; however AP-42 values should be updated for over half of the sources to reflect current data. The quantified uncertainty ranges were found to be 25-62% for A rated emission factors, 45-75% for B rated emission factors, 60-82% for C rated emission factors, and 69-86% for D rated emission factors, and 82-92% for E rated emission factors. 相似文献
196.
Mark T. Young Emily J. Rayfield Casey M. Holliday Lawrence M. Witmer David J. Button Paul Upchurch Paul M. Barrett 《Die Naturwissenschaften》2012,99(8):637-643
Sauropod dinosaurs were the largest terrestrial herbivores and pushed at the limits of vertebrate biomechanics and physiology. Sauropods exhibit high craniodental diversity in ecosystems where numerous species co-existed, leading to the hypothesis that this biodiversity is linked to niche subdivision driven by ecological specialisation. Here, we quantitatively investigate feeding behaviour hypotheses for the iconic sauropod Diplodocus. Biomechanical modelling, using finite element analysis, was used to examine the performance of the Diplodocus skull. Three feeding behaviours were modelled: muscle-driven static biting, branch stripping and bark stripping. The skull was found to be ‘over engineered’ for static biting, overall experiencing low stress with only the dentition enduring high stress. When branch stripping, the skull, similarly, is under low stress, with little appreciable difference between those models. When simulated for bark stripping, the skull experiences far greater stresses, especially in the teeth and at the jaw joint. Therefore, we refute the bark-stripping hypothesis, while the hypotheses of branch stripping and/or precision biting are both consistent with our findings, showing that branch stripping is a biomechanically plausible feeding behaviour for diplodocids. Interestingly, in all simulations, peak stress is observed in the premaxillary–maxillary ‘lateral plates’, supporting the hypothesis that these structures evolved to dissipate stress induced while feeding. These results lead us to conclude that the aberrant craniodental form of Diplodocus was adapted for food procurement rather than resisting high bite forces. 相似文献
197.
A simplistic aggregate model of global economic activity supports a 50-year visioning exercise with targets defined in terms of aggregate measures of global equity (convergence) and sustainability (contraction). Some ambitious combinations of these targets turn out to be infeasible even under the most favorable modeling assumptions. No contraction target (no reduction in fossil fuel consumption relative to the present) was possible, for example, if international capital transfers pushed per capita incomes in low-income countries above 33% of levels achieved in high-income countries. Lower prices for renewable alternatives to exhaustible resources generally made sustainability targets easier to achieve, but lower prices for renewable resources also made equity targets more difficult to achieve. Improved substitution between capital and labor made equity targets easier to achieve in relative terms, but improved substitution between capital and labor could make any given sustainability target more or less difficult to achieve. All the results suggest that it is possible to overstate the purported conflict between achieving sustainability and equity targets. The very transfers of international capital that would promote relative equity between high-income and low-income countries could also work to spread the incidence of achieving any sustainability target more evenly across their boundaries. 相似文献
198.
Emily Matthews 《生态毒理学报》2000,22(2):28-31
尽管继续有科学不确定性,但表明当前捕捞实践不可持续的证据与日俱增.在国家层次和国际层次上,人们越来越认真地对待关于过度捕捞及其对穷国食品保障的潜在威胁的告诫.近年来已经看到了一波改善渔业管理的协议.然而,无论在当地社区和传统可能处于危急之中的富国,还是在鱼类对于食品供应也具有根本重要性而且捕捞是沿海地区少数几种生活来源之一的穷国,对减少世界捕捞船队的规模都有强大阻力. 相似文献
199.
Using diatoms to assess the impacts of prehistoric, pre-industrial and modern land-use on Danish lakes 总被引:2,自引:1,他引:1
Emily G. Bradshaw Anne Birgitte Nielsen N. John Anderson 《Regional Environmental Change》2006,6(1-2):17-24
The impact of contemporary agriculture on Danish lakes is acknowledged to be extreme. In particular, high loading of nutrients
from agricultural soils contributes to the eutrophic conditions found in many of Denmark’s lakes. Palaeolimnological studies
have shown that human disturbance of the Danish landscape since the introduction of agriculture around 6,000 years ago has
had a major impact on lake ecosystems. The European Union’s Water Framework Directive requires an evaluation of reference
conditions for lakes, the conditions expected with only minimal human impact. Monitoring data and palaeolimnological studies
of Danish lakes demonstrate that many of the most detrimental effects of eutrophication have been experienced in recent decades.
A new study has suggested that the reference status for Danish lakes may be set to the status in ad 1850–1900, probably providing attainable, realistic restoration targets for many sites. The aims of this study were to explore
the impacts of past and contemporary land-use on Danish lakes, and to consider how appropriate the use of 1850 as a date to
define reference status is for these sites. Catchment land-cover data for ad 1800, taken from historical maps, and sedimentary diatom assemblages of the same age, from dated sediment cores, were used
to assess the impact of pre-industrial land-use on 20 Danish lakes. Analysis of contemporary land-cover data and surface-sediment
diatom assemblages for the 20 sites was also made. In-lake total phosphorus (TP) concentrations were estimated using the sedimentary
diatom assemblages and an existing calibration dataset for Danish lakes. The percentage of the lake catchment that was agricultural
land in ad 1800 explained 8.8% of the total variation in the diatom data. The land-cover variables ‘built-up areas’ and ‘plantations’,
together explained 16.9% of the variation in the diatom data for the modern samples. Diatom-inferred TP concentrations were
high for both ad 1800 (mean 112 μg TP L−1) and the present (mean 122 μg TP L−1), the latter estimates reflecting efforts in recent decades to reduce nutrient loading to Danish lakes following very high
levels of nutrient enrichment post-1950. The data presented highlight the impact that human activities 200 years ago, particularly
agriculture, had on Danish lake systems. The long cultural history and major anthropogenic disturbance of the Danish landscape
mean that true reference conditions for lakes (or ‘baseline’ conditions, those found prior to human impacts) can be found
only by considering century to millennial timescales. 相似文献
200.
Creating a habitat classification and mapping system for marine and coastal ecosystems is a daunting challenge due to the
complex array of habitats that shift on various spatial and temporal scales. To meet this challenge, several countries have,
or are developing, national classification systems and mapping protocols for marine habitats. To be effectively applied by
scientists and managers it is essential that classification systems be comprehensive and incorporate pertinent physical, geological,
biological, and anthropogenic habitat characteristics. Current systems tend to provide over-simplified conceptual structures
that do not capture biological habitat complexity, marginalize anthropogenic features, and remain largely untested at finer
scales. We propose a multi-scale hierarchical framework with a particular focus on finer scale habitat classification levels
and conceptual schematics to guide habitat studies and management decisions. A case study using published data is included
to compare the proposed framework with existing schemes. The example demonstrates how the proposed framework’s inclusion of
user-defined variables, a combined top-down and bottom-up approach, and multi-scale hierarchical organization can facilitate
examination of marine habitats and inform management decisions. 相似文献