全文获取类型
收费全文 | 1110篇 |
免费 | 29篇 |
国内免费 | 9篇 |
专业分类
安全科学 | 73篇 |
废物处理 | 37篇 |
环保管理 | 297篇 |
综合类 | 85篇 |
基础理论 | 315篇 |
环境理论 | 3篇 |
污染及防治 | 201篇 |
评价与监测 | 86篇 |
社会与环境 | 45篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 10篇 |
2022年 | 14篇 |
2021年 | 15篇 |
2020年 | 16篇 |
2019年 | 13篇 |
2018年 | 25篇 |
2017年 | 32篇 |
2016年 | 42篇 |
2015年 | 26篇 |
2014年 | 35篇 |
2013年 | 78篇 |
2012年 | 53篇 |
2011年 | 73篇 |
2010年 | 51篇 |
2009年 | 42篇 |
2008年 | 62篇 |
2007年 | 71篇 |
2006年 | 63篇 |
2005年 | 43篇 |
2004年 | 47篇 |
2003年 | 46篇 |
2002年 | 36篇 |
2001年 | 21篇 |
2000年 | 12篇 |
1999年 | 20篇 |
1998年 | 18篇 |
1997年 | 15篇 |
1996年 | 21篇 |
1995年 | 23篇 |
1994年 | 15篇 |
1993年 | 13篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 9篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1968年 | 1篇 |
1938年 | 1篇 |
排序方式: 共有1148条查询结果,搜索用时 359 毫秒
911.
Controlling range expansion in habitat networks by adaptively targeting source populations
下载免费PDF全文
![点击此处可从《Conservation biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Karlo Hock Nicholas H. Wolff Roger Beeden Jessica Hoey Scott A. Condie Kenneth R. N. Anthony Hugh P. Possingham Peter J. Mumby 《Conservation biology》2016,30(4):856-866
Controlling the spread of invasive species, pests, and pathogens is often logistically limited to interventions that target specific locations at specific periods. However, in complex, highly connected systems, such as marine environments connected by ocean currents, populations spread dynamically in both space and time via transient connectivity links. This results in nondeterministic future distributions of species in which local populations emerge dynamically and concurrently over a large area. The challenge, therefore, is to choose intervention locations that will maximize the effectiveness of the control efforts. We propose a novel method to manage dynamic species invasions and outbreaks that identifies the intervention locations most likely to curtail population expansion by selectively targeting local populations most likely to expand their future range. Critically, at any point during the development of the invasion or outbreak, the method identifies the local intervention that maximizes the long‐term benefit across the ecosystem by restricting species’ potential to spread. In so doing, the method adaptively selects the intervention targets under dynamically changing circumstances. To illustrate the effectiveness of the method we applied it to controlling the spread of crown‐of‐thorns starfish (Acanthaster sp.) outbreaks across Australia's Great Barrier Reef. Application of our method resulted in an 18‐fold relative improvement in management outcomes compared with a random targeting of reefs in putative starfish control scenarios. Although we focused on applying the method to reducing the spread of an unwanted species, it can also be used to facilitate the spread of desirable species through connectivity networks. For example, the method could be used to select those fragments of habitat most likely to rebuild a population if they were sufficiently well protected. 相似文献
912.
913.
Renee G. Seidler Ryan A. Long Joel Berger Scott Bergen Jon P. Beckmann 《Conservation biology》2015,29(1):99-109
In much of the world, the persistence of long‐distance migrations by mammals is threatened by development. Even where human population density is relatively low, there are roads, fencing, and energy development that present barriers to animal movement. If we are to conserve species that rely on long‐distance migration, then it is critical that we identify existing migration impediments. To delineate stopover sites associated with anthropogenic development, we applied Brownian bridge movement models to high‐frequency locations of pronghorn (Antilocapra americana) in the Greater Yellowstone Ecosystem. We then used resource utilization functions to assess the threats to long‐distance migration of pronghorn that were due to fences and highways. Migrating pronghorn avoided dense developments of natural gas fields. Highways with relatively high volumes of traffic and woven‐wire sheep fence acted as complete barriers. At crossings with known migration bottlenecks, use of high?quality forage and shrub habitat by pronghorn as they approached the highway was lower than expected based on availability of those resources. In contrast, pronghorn consistently utilized high?quality forage close to the highway at crossings with no known migration bottlenecks. Our findings demonstrate the importance of minimizing development in migration corridors in the future and of mitigating existing pressure on migratory animals by removing barriers, reducing the development footprint, or installing crossing structures. Identificación de los Impedimentos para las Migraciones de Larga Distancia de Mamíferos 相似文献
914.
915.
Sara Dubois Nicole Fenwick Erin A. Ryan Liv Baker Sandra E. Baker Ngaio J. Beausoleil Scott Carter Barbara Cartwright Federico Costa Chris Draper John Griffin Adam Grogan Gregg Howald Bidda Jones Kate E. Littin Amanda T. Lombard David J. Mellor Daniel Ramp Catherine A. Schuppli David Fraser 《Conservation biology》2017,31(4):753-760
Human–wildlife conflicts are commonly addressed by excluding, relocating, or lethally controlling animals with the goal of preserving public health and safety, protecting property, or conserving other valued wildlife. However, declining wildlife populations, a lack of efficacy of control methods in achieving desired outcomes, and changes in how people value animals have triggered widespread acknowledgment of the need for ethical and evidence‐based approaches to managing such conflicts. We explored international perspectives on and experiences with human–wildlife conflicts to develop principles for ethical wildlife control. A diverse panel of 20 experts convened at a 2‐day workshop and developed the principles through a facilitated engagement process and discussion. They determined that efforts to control wildlife should begin wherever possible by altering the human practices that cause human–wildlife conflict and by developing a culture of coexistence; be justified by evidence that significant harms are being caused to people, property, livelihoods, ecosystems, and/or other animals; have measurable outcome‐based objectives that are clear, achievable, monitored, and adaptive; predictably minimize animal welfare harms to the fewest number of animals; be informed by community values as well as scientific, technical, and practical information; be integrated into plans for systematic long‐term management; and be based on the specifics of the situation rather than negative labels (pest, overabundant) applied to the target species. We recommend that these principles guide development of international, national, and local standards and control decisions and implementation. 相似文献
916.
917.
Scott R. Shaw 《Conservation biology》2015,29(5):1489-1490
918.
919.
Nemo K. Klumpp K. Coleman M. Dondini K. Goulding A. Hastings Michael. B. Jones J. Leifeld B. Osborne M. Saunders T. Scott Y. A. Teh P. Smith 《Environmental Modeling and Assessment》2017,22(3):215-229
Carbon (C) emissions from anthropogenic land use have accelerated climate change. To reduce C emissions, dynamic models can be used to assess the impact of human drivers on terrestrial C sequestration. Model accuracy requires correct initialisation, since incorrect initialisation can influence the results obtained. Therefore, we sought to improve the initialisation of a process-based SOC model, RothC, which can estimate the effect of climate and land-use change on SOC. The most common initialisation involves running the model until equilibrium (‘spin-up run’), when the SOC pools stabilise (method 1). However, this method does not always produce realistic results. At our experimental sites, the observed SOC was not at equilibrium after 10 years, suggesting that the commonly used spin-up initialisation method assuming equilibrium might be improved. In addition to method 1, we tested two alternative initialisations for RothC that involved adjusting the total or individual SOC pool equilibrium values by regulating the C input during the entire spin-up initialisation period (method 2) and initialising each SOC pool with recently measured SOC values obtained by SOC fractionation (method 3). Analysis of the simulation accuracy for each model initialisation, quantified using the root mean square error (RMSE), indicated that a variant of method 2 that involved adjusting the equilibrium total SOC to observed values (method 2-T) generally showed less variation in the individual SOC pools and total SOC. Furthermore, as total SOC is the sum of all SOC pools, and because total SOC data are more readily available than the individual SOC pool data, we conclude that method 2-T is best for initialising RothC. 相似文献
920.
Scott Soby 《Journal of Agricultural and Environmental Ethics》2017,30(1):87-98
Two competing models have served as the basis for agricultural development policies. One is based on observations and assumptions of The Reverend Thomas Malthus in late eighteenth century Britain, and the other from the Danish economist Ester Boserup in the mid-twentieth century. However, rational agricultural development decisions can only be made using a model that incorporates assumptions based on a technically appropriate model that takes into account the currently status of global systems. A new development model may incorporate elements of both Neo-Malthusian and Boserupian economic-demographic models, but because the world has changed substantially, it can be neither of them alone, nor a hybrid of the two models without significant expansion and refinement. The principles espoused by Malthus and Boserup can thus be used as the starting points in a dialectic argument to arrive at a new agricultural development paradigm. 相似文献