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   1152篇
  免费   428篇
  国内免费   3篇
安全科学   2篇
废物处理   8篇
环保管理   11篇
综合类   8篇
基础理论   1543篇
污染及防治   5篇
评价与监测   2篇
社会与环境   3篇
灾害及防治   1篇
  2024年   1篇
  2023年   101篇
  2022年   84篇
  2021年   119篇
  2020年   117篇
  2019年   100篇
  2018年   81篇
  2017年   114篇
  2016年   105篇
  2015年   127篇
  2014年   138篇
  2013年   113篇
  2012年   81篇
  2011年   89篇
  2010年   112篇
  2009年   26篇
  2008年   39篇
  2007年   2篇
  2006年   1篇
  2005年   4篇
  2004年   1篇
  2003年   3篇
  2002年   5篇
  2001年   3篇
  2000年   2篇
  1999年   2篇
  1998年   5篇
  1997年   1篇
  1996年   1篇
  1994年   3篇
  1993年   1篇
  1992年   1篇
  1988年   1篇
排序方式: 共有1583条查询结果,搜索用时 15 毫秒
961.
Conservation goals at the start of the 21st century reflect a combination of contrasting ideas. Ideal nature is something that is historically intact but also futuristically flexible. Ideal nature is independent from humans, but also, because of the pervasiveness of human impacts, only able to reach expression through human management. These tensions emerge in current management rationales because scientists and managers are struggling to accommodate old and new scientific and cultural thinking, while also maintaining legal mandates from the past and commitments to preservation of individual species in particular places under the stresses of global change. Common management goals (such as integrity, wilderness, resilience), whether they are forward looking and focused on sustainability and change, or backward looking and focused on the persistence and restoration of historic states, tend to create essentialisms about how ecosystems should be. These essentialisms limit the options of managers to accommodate the dynamic, and often novel, response of ecosystems to global change. Essentialisms emerge because there is a tight conceptual coupling of place and historical species composition as an indicator of naturalness (e.g., normal, healthy, independent from humans). Given that change is increasingly the norm and ecosystems evolve in response, the focus on idealized ecosystem states is increasingly unwise and unattainable. To provide more open‐ended goals, we propose greater attention be paid to the characteristics of management intervention. We suggest that the way we interact with other species in management and the extent to which those interactions reflect the interactions among other biotic organisms, and also reflect our conservation virtues (e.g., humility, respect), influences our ability to cultivate naturalness on the landscape. We call this goal a natural practice (NP) and propose it as a framework for prioritizing and formulating how, when, and where to intervene in this period of rapid change. Desarrollo de una Práctica Natural para Adaptar Objetivos de Conservación al Cambio Global  相似文献   
962.
Conservationists need methods to conserve biological diversity while allowing species and communities to rearrange in response to a changing climate. We developed and tested such a method for northeastern North America that we based on physical features associated with ecological diversity and site resilience to climate change. We comprehensively mapped 30 distinct geophysical settings based on geology and elevation. Within each geophysical setting, we identified sites that were both connected by natural cover and that had relatively more microclimates indicated by diverse topography and elevation gradients. We did this by scoring every 405 ha hexagon in the region for these two characteristics and selecting those that scored >SD 0.5 above the mean combined score for each setting. We hypothesized that these high‐scoring sites had the greatest resilience to climate change, and we compared them with sites selected by The Nature Conservancy for their high‐quality rare species populations and natural community occurrences. High‐scoring sites captured significantly more of the biodiversity sites than expected by chance (p < 0.0001): 75% of the 414 target species, 49% of the 4592 target species locations, and 53% of the 2170 target community locations. Calcareous bedrock, coarse sand, and fine silt settings scored markedly lower for estimated resilience and had low levels of permanent land protection (average 7%). Because our method identifies—for every geophysical setting—sites that are the most likely to retain species and functions longer under a changing climate, it reveals natural strongholds for future conservation that would also capture substantial existing biodiversity and correct the bias in current secured lands.  相似文献   
963.
How to create and adjust governing institutions so that they align (fit) with complex ecosystem processes and structures across scales is an issue of increasing concern in conservation. It is argued that lack of such social‐ecological fit makes governance and conservation difficult, yet progress in explicitly defining and rigorously testing what constitutes a good fit has been limited. We used a novel modeling approach and data from case studies of fishery and forest conservation to empirically test presumed relationships between conservation outcomes and certain patterns of alignment of social‐ecological interdependences. Our approach made it possible to analyze conservation outcome on a systems level while also providing information on how individual actors are positioned in the complex web of social‐ecological interdependencies. We found that when actors who shared resources were also socially linked, conservation at the level of the whole social‐ecological system was positively affected. When the scales at which individual actors used resources and the scale at which ecological resources were interconnected to other ecological resources were aligned through tightened feedback loops, conservation outcome was better than when they were not aligned. The analysis of individual actors’ positions in the web of social‐ecological interdependencies was helpful in understanding why a system has a certain level of social‐ecological fit. Results of analysis of positions showed that different actors contributed in very different ways to achieve a certain fit and revealed some underlying difference between the actors, for example in terms of actors’ varying rights to access and use different ecological resources. El Éxito de la Conservación como Función de una Buena Alineación de Estructuras y Procesos Sociales y Ecológicos  相似文献   
964.
Dialogue about complex science and society issues is important for contemporary conservation agendas. Conferences provide an appropriate space for such dialogue, but despite its recognized worth, best practices for facilitating active dialogue are still being explored. Face‐to‐face (FTF) and computer‐mediated communication (CMC) are two approaches to facilitating dialogue that have different strengths. We assessed the use of these approaches to create dialogue on cultural perspectives of conservation and biodiversity at a national ecology conference. In particular, we aimed to evaluate their potential to enhance dialogue through their integrated application. We used an interactive blog to generate CMC on participant‐sourced issues and to prime subsequent discussion in an FTF conference workshop. The quantity and quality of both CMC and FTF discussion indicated that both approaches were effective in building dialogue. Prior to the conference the blog averaged 126 views per day, and 44 different authors contributed a total of 127 comments. Twenty‐five participants subsequently participated in active FTF discussion during a 3‐h workshop. Postconference surveys confirmed that CMC had developed participants’ thinking and deepened FTF dialogue; 88% indicated specifically that CMC helped facilitate the FTF discussion. A further 83% of respondents concluded that preliminary blog discussion would be useful for facilitating dialogue at future conferences. Construcción del Diálogo sobre Problemas Complejos de Conservación en un Escenario de Conferencia  相似文献   
965.
Improving public awareness of protected wetlands facilitates sustainable wetland management, which depends on public participation. One way of gauging public interest is by tracking Internet search behavior (ISB). We assessed public awareness of issues related to protected wetland areas (PWAs) in South Korea by examining the frequencies of specific queries (PWAs, Ramsar, Upo wetland, Sunchon Bay, etc.) using relative search volumes (RSVs) obtained from an Internet search engine. RSV shows how many times a search term is used relative to a second search term during a specific period. Public awareness of PWAs changed from 2007 to 2013. Initially the majority of Internet searches were related to the most well‐known tidal and inland wetlands Sunchon Bay and Upo wetlands, which are the largest existing wetlands in Korea with the greatest historical exposure. Public awareness, as reflected in RSVs, of wetlands increased significantly following PWA designation for the wetlands in 2008, which followed the Ramsar 10th Conference of Contracting Parties to the Convention on Wetlands (COP10) meeting. Public interest was strongly correlated to the number of news articles in the popular media, as evidenced by the increase in Internet searches for specific wetlands and words associated with specific wetlands. Correspondingly, the number of visitors to specific wetlands increased. To increase public interest in wetlands, wetland aspects that enhance wetland conservation should be promoted by the government and enhanced via public education. Our approach can be used to gauge public awareness and participation in a wide range of conservation efforts.  相似文献   
966.
Effective conservation of biological diversity on private lands will require changes in land‐use policy and development practice. Conservation development (CD) is an alternative form of residential development in which homes are built on smaller lots and clustered together and the remainder of the property is permanently protected for conservation purposes. We assessed the degree to which CD is permitted and encouraged by local land‐use regulations in 414 counties in the western United States. Thirty‐two percent of local planning jurisdictions have adopted CD ordinances, mostly within the past 10 years. CD ordinances were adopted in counties with human population densities that were 3.0 times greater and in counties with 2.5 times more land use at urban, suburban, and exurban densities than counties without CD ordinances. Despite strong economic incentives for CD (e.g., density bonuses, which allow for a mean of 66% more homes to be built per subdivision area), several issues may limit the effectiveness of CD for biological diversity conservation. Although most CD ordinances required a greater proportion of the site area be protected than in a typical residential development, just 13% (n = 17) of the ordinances required an ecological site analysis to identify and map features that should be protected. Few CD ordinances provided guidelines regarding the design and configuration of the protected lands, including specifying a minimum size for protected land parcels or encouraging contiguity with other protected lands within or near to the site. Eight percent (n =11) of CD ordinances encouraged consultation with a biological expert or compliance with a conservation plan. We recommend that conservation scientists help to improve the effectiveness of CD by educating planning staff and government officials regarding biological diversity conservation, volunteering for their local planning boards, or consulting on development reviews. Guías e Incentivos para el Desarrollo de la Conservación en Regulaciones de Uso Local de Suelos  相似文献   
967.
Categorization of the status of populations, species, and ecosystems underpins most conservation activities. Status is often based on how a system's current indicator value (e.g., change in abundance) relates to some threshold of conservation concern. Receiver operating characteristic (ROC) curves can be used to quantify the statistical reliability of indicators of conservation status and evaluate trade‐offs between correct (true positive) and incorrect (false positive) classifications across a range of decision thresholds. However, ROC curves assume a discrete, binary relationship between an indicator and the conservation status it is meant to track, which is a simplification of the more realistic continuum of conservation status, and may limit the applicability of ROC curves in conservation science. We describe a modified ROC curve that treats conservation status as a continuum rather than a discrete state. We explored the influence of this continuum and typical sources of variation in abundance that can lead to classification errors (i.e., random variation and measurement error) on the true and false positive rates corresponding to varying decision thresholds and the reliability of change in abundance as an indicator of conservation status, respectively. We applied our modified ROC approach to an indicator of endangerment in Pacific salmon (Oncorhynchus nerka) (i.e., percent decline in geometric mean abundance) and an indicator of marine ecosystem structure and function (i.e., detritivore biomass). Failure to treat conservation status as a continuum when choosing thresholds for indicators resulted in the misidentification of trade‐offs between true and false positive rates and the overestimation of an indicator's reliability. We argue for treating conservation status as a continuum when ROC curves are used to evaluate decision thresholds in indicators for the assessment of conservation status. Determinación de Umbrales de Decisiones y Evaluación delos Indicadores cuando se Mide el Estado de de Conservación como un Continuo  相似文献   
968.
The contribution of renewable energy to meet worldwide demand continues to grow. Wind energy is one of the fastest growing renewable sectors, but new wind facilities are often placed in prime wildlife habitat. Long‐term studies that incorporate a rigorous statistical design to evaluate the effects of wind facilities on wildlife are rare. We conducted a before‐after‐control‐impact (BACI) assessment to determine if wind facilities placed in native mixed‐grass prairies displaced breeding grassland birds. During 2003–2012, we monitored changes in bird density in 3 study areas in North Dakota and South Dakota (U.S.A.). We examined whether displacement or attraction occurred 1 year after construction (immediate effect) and the average displacement or attraction 2–5 years after construction (delayed effect). We tested for these effects overall and within distance bands of 100, 200, 300, and >300 m from turbines. We observed displacement for 7 of 9 species. One species was unaffected by wind facilities and one species exhibited attraction. Displacement and attraction generally occurred within 100 m and often extended up to 300 m. In a few instances, displacement extended beyond 300 m. Displacement and attraction occurred 1 year after construction and persisted at least 5 years. Our research provides a framework for applying a BACI design to displacement studies and highlights the erroneous conclusions that can be made without the benefit of adopting such a design. More broadly, species‐specific behaviors can be used to inform management decisions about turbine placement and the potential impact to individual species. Additionally, the avoidance distance metrics we estimated can facilitate future development of models evaluating impacts of wind facilities under differing land‐use scenarios.  相似文献   
969.
970.
Wildlife consumption can be viewed as an ecosystem provisioning service (the production of a material good through ecological functioning) because of wildlife's ability to persist under sustainable levels of harvest. We used the case of wildlife harvest and consumption in northeastern Madagascar to identify the distribution of these services to local households and communities to further our understanding of local reliance on natural resources. We inferred these benefits from demand curves built with data on wildlife sales transactions. On average, the value of wildlife provisioning represented 57% of annual household cash income in local communities from the Makira Natural Park and Masoala National Park, and harvested areas produced an economic return of U.S.$0.42 ha?1· year?1. Variability in value of harvested wildlife was high among communities and households with an approximate 2 orders of magnitude difference in the proportional value of wildlife to household income. The imputed price of harvested wildlife and its consumption were strongly associated (p< 0.001), and increases in price led to reduced harvest for consumption. Heightened monitoring and enforcement of hunting could increase the costs of harvesting and thus elevate the price and reduce consumption of wildlife. Increased enforcement would therefore be beneficial to biodiversity conservation but could limit local people's food supply. Specifically, our results provide an estimate of the cost of offsetting economic losses to local populations from the enforcement of conservation policies. By explicitly estimating the welfare effects of consumed wildlife, our results may inform targeted interventions by public health and development specialists as they allocate sparse funds to support regions, households, or individuals most vulnerable to changes in access to wildlife. Valoración Económica de la Caza de Subsistencia de Vida Silvestre en Madagascar  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