全文获取类型
收费全文 | 353篇 |
免费 | 1篇 |
专业分类
安全科学 | 3篇 |
废物处理 | 2篇 |
环保管理 | 169篇 |
综合类 | 71篇 |
基础理论 | 54篇 |
污染及防治 | 31篇 |
评价与监测 | 14篇 |
社会与环境 | 8篇 |
灾害及防治 | 2篇 |
出版年
2022年 | 1篇 |
2021年 | 10篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 11篇 |
2015年 | 8篇 |
2014年 | 5篇 |
2013年 | 15篇 |
2012年 | 6篇 |
2011年 | 36篇 |
2010年 | 16篇 |
2009年 | 40篇 |
2008年 | 26篇 |
2007年 | 15篇 |
2006年 | 15篇 |
2005年 | 8篇 |
2004年 | 11篇 |
2003年 | 9篇 |
2002年 | 10篇 |
2001年 | 11篇 |
2000年 | 12篇 |
1999年 | 8篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有354条查询结果,搜索用时 31 毫秒
201.
202.
高速公路人文景观评价的难点在于人文景观影响因素的确定和指标的量化,由于其不确定性而且受到主观因素的影响很大,将其尽量量化是较好的办法.本文结合高速公路人文景观特点提出了其评价指标体系,并通过层次分析法和模糊综合评价对各指标进行了具体分析. 相似文献
203.
As the human activity footprint grows, land-use decisions play an increasing role in determining the future of plant and animal species. Studies have shown that urban and agricultural development cannot only harm species populations directly through habitat destruction, but also by destroying the corridors that connect habitat patches and populations within a metapopulation. Without these pathways, populations can encounter inbreeding depression and degeneration, which can increase death rates and lower rates of reproduction. This article describes the development and application of the FRAGGLE model, a spatial system dynamics model designed to calculate connectivity indices among populations. FRAGGLE can help planners and managers identify the relative contribution of populations associated with habitat patches to future populations in those patches, taking into account the importance of interstitial land to migration success. The model is applied to the gopher tortoise (Gopherus polyphemus), a threatened species whose southeastern U.S. distribution has diminished significantly within its native range due to agricultural and urban development over the last several decades. This model is parameterized with life history and movement traits of the gopher tortoise in order to simulate population demographics and spatial distribution within an area in west-central Georgia that supports a significant tortoise population. The implications of this simulation modeling effort are demonstrated using simple landscape representations and a hypothetical on land-use management scenario. Our findings show that development resulting in even limited habitat losses (10%) may lead to significant increases in fragmentation as measured by a loss in the rate of dispersions (31%) among area subpopulations. 相似文献
204.
Thomas D. Harwood Xiangming Xu Marco Pautasso Mike J. Jeger Michael W. Shaw 《Ecological modelling》2009
We developed a stochastic simulation model incorporating most processes likely to be important in the spread of Phytophthora ramorum and similar diseases across the British landscape (covering Rhododendron ponticum in woodland and nurseries, and Vaccinium myrtillus in heathland). The simulation allows for movements of diseased plants within a realistically modelled trade network and long-distance natural dispersal. A series of simulation experiments were run with the model, representing an experiment varying the epidemic pressure and linkage between natural vegetation and horticultural trade, with or without disease spread in commercial trade, and with or without inspections-with-eradication, to give a 2 × 2 × 2 × 2 factorial started at 10 arbitrary locations spread across England. Fifty replicate simulations were made at each set of parameter values. Individual epidemics varied dramatically in size due to stochastic effects throughout the model. Across a range of epidemic pressures, the size of the epidemic was 5–13 times larger when commercial movement of plants was included. A key unknown factor in the system is the area of susceptible habitat outside the nursery system. Inspections, with a probability of detection and efficiency of infected-plant removal of 80% and made at 90-day intervals, reduced the size of epidemics by about 60% across the three sectors with a density of 1% susceptible plants in broadleaf woodland and heathland. Reducing this density to 0.1% largely isolated the trade network, so that inspections reduced the final epidemic size by over 90%, and most epidemics ended without escape into nature. Even in this case, however, major wild epidemics developed in a few percent of cases. Provided the number of new introductions remains low, the current inspection policy will control most epidemics. However, as the rate of introduction increases, it can overwhelm any reasonable inspection regime, largely due to spread prior to detection. 相似文献
205.
Preface to the selected papers on spatially explicit landscape modelling: Current practices and challenges 总被引:1,自引:0,他引:1
In the past 30 years, the notion of landscape has emerged in ecology as a result of both theoretical strategies and practical aspects of land use. This has generated a variety of computerized models addressing both objectives and techniques. Scientists model landscapes for at least two reasons: to better understand the landscape dynamics themselves (called intrinsic needs) and to offer a realistic frame to support other ecological processes (extrinsic needs). This special issue concerns both needs and illustrates the way socioeconomic and/or ecological mechanisms of various landscapes have been understood through modelling approaches. It outlines the links between landscape and model concepts, focusing on one hand on several landscape types (agricultural, forested and aquatic) and on the other hand on several landscape model characteristics (explicit or neutral, dynamic or static, patchy or continuous and multi- or mono-scale). The patterns and processes of each landscape model presented in this issue, in particular, should be analysed in order to highlight the way they are contributing to the landscape ecology discipline. We finally argue that the discipline can now offer a theoretical dimension to landscape dynamics, aiming at understanding the possible mechanism unity underlying this complex object. 相似文献
206.
景观及视觉影响评价初探 总被引:10,自引:0,他引:10
总结和论述了景观及视觉影响评价的概念及评价的过程、内容与方法等,结合我国的实际情况提出了开展此项工作的建议。由于景观及视觉影响不同于通常的污染影响,具有直接可见性和不易改变性等特点,故应及早重视,使发展项目所制定的计划与景观及视觉环境相协调。该评价方法主要包括计算机技术支持下的图形叠加法和GIS法等。 相似文献
207.
208.
Implications of Rural–Urban Migration for Conservation of the Atlantic Forest and Urban Growth in Misiones,Argentina (1970–2030) 总被引:2,自引:0,他引:2
Global trends of increasing rural–urban migration and population urbanization could provide opportunities for nature conservation,
particularly in regions where deforestation is driven by subsistence agriculture. We analyzed the role of rural population
as a driver of deforestation and its contribution to urban population growth from 1970 to the present in the Atlantic Forest
of Argentina, a global conservation priority. We created future land-use-cover scenarios based on human demographic parameters
and the relationship between rural population and land-cover change between 1970 and 2006. In 2006, native forest covered
50% of the province, but by 2030 all scenarios predicted a decrease that ranged from 18 to 39% forest cover. Between 1970
and 2001, rural migrants represented 20% of urban population growth and are expected to represent less than 10% by 2030. This
modeling approach shows how rural–urban migration and land-use planning can favor nature conservation with little impact on
urban areas. 相似文献
209.
Duretz S Drouet JL Durand P Hutchings NJ Theobald MR Salmon-Monviola J Dragosits U Maury O Sutton MA Cellier P 《Environmental pollution (Barking, Essex : 1987)》2011,159(11):3162-3170
Modelling nitrogen transfer and transformation at the landscape scale is relevant to estimate the mobility of the reactive forms of nitrogen (Nr) and the associated threats to the environment. Here we describe the development of a spatially and temporally explicit model to integrate Nr transfer and transformation at the landscape scale. The model couples four existing models, to simulate atmospheric, farm, agro-ecosystem and hydrological Nr fluxes and transformations within a landscape. Simulations were carried out on a theoretical landscape consisting of pig-crop farms interspersed with unmanaged ecosystems. Simulation results illustrated the effect of spatial interactions between landscape elements on Nr fluxes and losses to the environment. More than 10% of the total N2O emissions were due to indirect emissions. The nitrogen budgets and transformations of the unmanaged ecosystems varied considerably, depending on their location within the landscape. The model represents a new tool for assessing the effect of changes in landscape structure on Nr fluxes. 相似文献
210.
South Africa's moist grassland harbours globally significant biodiversity, supplies essential ecosystem services, supports crop and livestock agriculture, forestry and settlement, yet is poorly conserved. Ongoing transformation and limited opportunity for expanding the protected area network require instead that biodiversity conservation is 'mainstreamed' within other land uses. This exercise sought to identify the relative compatibility of 10 land uses (conservation, livestock or game ranching, tourism/recreation, rural settlement, dryland cropping, irrigated cropping, dairy farming, plantation forestry, and urban settlement) with maintaining biodiversity integrity. This was assessed using 46 indicators for biodiversity integrity that covered landscape composition, structure, and functioning. Data was integrated into a single measure per land use through application of the analytic hierarchy process, with supporting information gained from interviews with experts. The rank order of importance amongst indicators was landscape structure, functioning and composition. Consistent differences among land uses for all three categories revealed two clear groupings. Conservation, livestock or game ranching had the lowest impact and retained substantial natural asset, while that for tourism/recreation was intermediate. All other land uses had a severe impact. Impact on biodiversity integrity depended mainly on the extent of transformation and fragmentation, which accounted for the greatest impact on habitats and species, and impairment of landscape functioning. It is suggested that a strategic intervention for maintaining biodiversity integrity of moist grassland is to support livestock or game ranching and limit ongoing urban sprawl. 相似文献