全文获取类型
收费全文 | 541篇 |
免费 | 31篇 |
国内免费 | 29篇 |
专业分类
安全科学 | 32篇 |
废物处理 | 2篇 |
环保管理 | 249篇 |
综合类 | 129篇 |
基础理论 | 82篇 |
污染及防治 | 26篇 |
评价与监测 | 39篇 |
社会与环境 | 32篇 |
灾害及防治 | 10篇 |
出版年
2024年 | 3篇 |
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 14篇 |
2020年 | 15篇 |
2019年 | 12篇 |
2018年 | 14篇 |
2017年 | 18篇 |
2016年 | 20篇 |
2015年 | 13篇 |
2014年 | 22篇 |
2013年 | 30篇 |
2012年 | 22篇 |
2011年 | 39篇 |
2010年 | 25篇 |
2009年 | 39篇 |
2008年 | 39篇 |
2007年 | 41篇 |
2006年 | 25篇 |
2005年 | 11篇 |
2004年 | 14篇 |
2003年 | 13篇 |
2002年 | 11篇 |
2001年 | 7篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 10篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 8篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1973年 | 1篇 |
排序方式: 共有601条查询结果,搜索用时 968 毫秒
511.
Research has found that human-caused noise can detract from the quality of the visitor experience in national parks and related
areas. Moreover, impacts to the visitor experience can be managed by formulating indicators and standards of quality as suggested
in park and outdoor recreation management frameworks, such as Visitor Experience and Resource Protection (VERP), as developed
by the U.S. National Park Service. The research reported in this article supports the formulation of indicators and standards
of quality for human-caused noise at Muir Woods National Monument, California. Phase I identified potential indicators of
quality for the soundscape of Muir Woods. A visitor “listening exercise” was conducted, where respondents identified natural
and human-caused sounds heard in the park and rated the degree to which each sound was “pleasing” or “annoying.” Certain visitor-caused
sounds such as groups talking were heard by most respondents and were rated as annoying, suggesting that these sounds may
be a good indicator of quality. Loud groups were heard by few people but were rated as highly annoying, whereas wind and water
were heard by most visitors and were rated as highly pleasing. Phase II measured standards of quality for visitor-caused noise.
Visitors were presented with a series of 30-second audio clips representing increasing amounts of visitor-caused sound in
the park. Respondents were asked to rate the acceptability of each audio clip on a survey. Findings suggest a threshold at
which visitor-caused sound is judged to be unacceptable, and is therefore considered as noise. A parallel program of sound
monitoring in the park found that current levels of visitor-caused sound sometimes violate this threshold. Study findings
provide an empirical basis to help formulate noise-related indicators and standards of quality in parks and related areas. 相似文献
512.
513.
Podlaski R 《Environmental monitoring and assessment》2007,135(1-3):339-351
Tree damage, gauged by the amount of defoliation, is one of the basic criteria used to determine treatments for protected
and economic forests. Monitoring should include an assessment of the degree of tree damage in different spatial scales. Therefore,
in addition to the commonly applied large-area methods, small-area methods should be used. The aim of the paper is to present
the results of the accuracy assessment of a small-area method, proposed by Podlaski (2005) [Podlaski, R. (2005). Inventory of the degree of tree defoliation in small areas. Forest Ecology and Management, 215, 361–377], for monitoring the degree of tree damage. The degree of tree damage was shown in sub-blocks P3 of the system of information on natural environment (SINUS). To estimate the spatial distribution of the degree of tree defoliation,
survey sampling, based on simple random sampling with replacement (SRSWR), was used. The degree of damage to fir (Abies alba Mill.) and beech (Fagus sylvatica L.) was analysed in the Święty Krzyż forest section in the Świętokrzyski National Park. The maximum total estimation errors
for the proportion of trees with a degree zero of damage, and with second and third degrees of damage together (for α = 0.05) were at most 30.8% for fir and 24.3% for beech trees. For standard, small-area evaluations, these are satisfactory
values. In the Święty Krzyż forest section, the number of P3 sub-blocks with 0.00–5.00% of undamaged trees and with 80.01–100.00% of moderately- or severely-damaged trees was significantly
greater for fir than for beech. These results indicate that the fir population was unhealthier than the beech group in the
study area. P3 sub-blocks of the SINUS system, in which the proportion of the healthiest trees was highest, were situated at the forest
margin, bordering on meadows and arable fields (in the case of fir) and forming dense patches consisting of several sub-blocks,
or occurring singly in the whole study area (in the case of beech). The results show the significant differentiation of forest
tree health in small areas. 相似文献
514.
This study provides a method for assessing a multiplicity of environmental factors in red spruce growth in the Great Smoky Mountains National Park (GSMNP) of Southeastern USA. Direct and indirect factors in the annual growth increment are first organized into a schematic input-output envirogram (ARIRS), and this information is then used to construct a simulation model (ARIM). The envirogram represents a structured conceptualization of most environmental factors involved in growth, as developed from relevant literature. This interdisciplinary synthesis distinguishes direct vs. indirect factors in growth and takes account of the systems ecology concept that indirect factors may be as important as or more important than direct ones in regulating growth. The ARIRS envirogram summarizes hierarchically organized, within- and cross-scale, local-to-global interactions, and its construction makes it obvious that growth is influenced by many cross-scale spatiotemporal interactions. More research on genecology is still needed to clarify the role of phenotypic plasticity and adaptive capacity in nutrient cycling, global change, and human disturbance. 相似文献
515.
利用ISSR分子标记技术对湖北省大贵寺国家森林公园野生青檀(Pteroceltis tatarinowii Maxim.)居群进行遗传多样性分析。用11条ISSR引物对6个青檀居群64个样品进行扩增,扩增片段长度在200bp至3000bp之间,检测到179个位点,其中多态位点165个,多态位点百分率(P)为92.14%。青檀在物种水平上的Nei基因多样性指数(胁)和Shannon信息指数∽分别为0.273和0.423,在居群水平上分别为0.225和0.343,显示出青檀有着较高的遗传多样性。居群间的遗传分化系数(Gsr)为0.192,表明青檀居群间存在着较大的遗传分化;UPGMA聚类分析表明遗传距离与海拔差距有一定的相关性,相邻海拔的青檀居群间遗传距离较近。不同海拔导致的异质生境可能是影响青檀居群遗传分化的主要原因。 相似文献
516.
Diego Lisbona Joseph Januszewski Helen Balmforth Mike Wardman 《Process Safety and Environmental Protection》2011,89(6):404-414
QuickRisk is a quantitative risk assessment tool developed at the Health and Safety Laboratory for use in assessing societal risk around onshore major hazard installations to inform land-use planning decisions. It uses release scenario information, parameterised consequence models, weather data, and population data from the National Population Database (NPD).This paper describes enhancements to the NPD methodology to include workplace populations. It describes the novel numerical, graphical and geographical representations of societal risk produced by QuickRisk. F–N data are analysed in terms of scenario FN curves and Delta PLL vs. N curves, where PLL is potential loss of life. The Delta PLL curves could be useful for comparison of FN curves against FN criterion lines or other FN data on a PLL basis. Geographical representations generated from PLL density maps show: the distribution of PLL dominating release scenarios or the percentage of risk contributed by the PLL-dominant release scenario, the maximum number of fatalities associated with the worst-case event, and the associated release scenario. Geographical representations are also generated of the maximum population that would meet a PLL density criterion, and the relative population change that would match a given PLL density criterion.These novel representations of societal risk could be useful for more effective communication between stakeholders on the risk levels in the vicinity of major hazard installations. 相似文献
517.
Karen Bailey Jonathan Salerno Peter Newton Robert Bitariho Shamilah Namusisi Rogers Tinkasimire Joel Hartter 《Ambio》2021,50(7):1351
In biodiversity hotspots, there is often tension between human needs and conservation, exacerbated when protected areas prevent access to natural resources. Forest-dependent people may compensate for exclusion by managing unprotected forests or cultivating planted woodlots. Outside Bwindi Impenetrable National Park in Uganda, household wood product needs are high and population growth puts pressure on the environment. We investigated the role of privately and collectively managed woodlots in provisioning wood products and supporting local livelihoods. We found that households relied heavily on woodlots for daily needs and as resources during time of need. We also found that locally relevant social institutions, called stretcher groups, played a role in the management of woodlots, providing shared community resources. Privately and collectively owned woodlots support local livelihoods and wood product needs in the region. Long-term management of forests in Uganda should consider the value of woodlots and the mechanisms required to support them. 相似文献
518.
本文对中国合格评定国家认可委员会能源之星实验室认可计划进行政策解读和明晰,并对能源之星实验室认可中出现的实验室比对、产品分类及检测方法,检测能力表述这三个直接影响实验室获得注册的突出关键问题进行了详细的分析和研究。为有意申请能源之星实验室认可的实验室进行指导,并为获得能源之星实验室认可的实验室最终获得美国环保署的最终注册提供借鉴。 相似文献
519.
《Environmental Communication: A Journal of Nature and Culture》2013,7(4):469-474
Ken Burns, over the course of a long and celebrated career, has developed an effective and popular formula for his documentary films, and a comfortable relationship with the Public Broadcasting System. With such a convincing, accomplished style, his work has the opportunity to tackle ecological concerns in his latest series, but Burns chooses not to do so, offering no explicit lessons to apply to current problems. While stressing the importance of the people's parks, ecological debates on land use for future citizen-owners are minimized; the conflict of conservation versus preservation policies is barely differentiated. With the skill and reputation of Burns, his researchers, and his production team, there is a singular opportunity for their films to address ecological issues, creating productive conversation using America as a microcosm of the larger global issues faced today. Nostalgia and national pride are useful, but those attributes should be channeled to look to the future. 相似文献
520.
Due to rapid industrialization, with high population density and constraints of land, it is expected that level of risks arising from the hazardous industries will increase in India in the coming decades. However, 30 years after the Bhopal accident (1984), except a few discrete regulations, there is as yet no integrated system for assessing and managing risks arising out of these hazardous industries in India. The gravity of aspects related to the management of industrial risk still remains crucially important. In particular, there is no standard guideline on risk analysis methodology, acceptability or tolerability criteria, nor is there an accident database or a risk reduction strategy for the areas where risk levels are already high. On top of this, there are technical and legislative gaps in the institutional framework to implement any of the above mentioned issues. With the backdrop of the Bhopal gas tragedy, the objective of this paper is therefore to evaluate the effectiveness of a comprehensive risk assessment framework for the emerging economy of India, in order to control and/or to reduce the risk level that exists. In this context, regulations and policies pertaining to industrial risk assessment were reviewed. 相似文献