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   99篇
  免费   74篇
  国内免费   13篇
安全科学   11篇
环保管理   22篇
综合类   45篇
基础理论   80篇
污染及防治   7篇
评价与监测   2篇
社会与环境   7篇
灾害及防治   12篇
  2023年   2篇
  2022年   4篇
  2021年   9篇
  2020年   2篇
  2019年   4篇
  2018年   65篇
  2017年   2篇
  2016年   3篇
  2015年   1篇
  2014年   9篇
  2013年   4篇
  2012年   2篇
  2011年   7篇
  2010年   4篇
  2009年   10篇
  2008年   6篇
  2007年   9篇
  2006年   9篇
  2005年   5篇
  2004年   2篇
  2003年   4篇
  2002年   2篇
  2001年   3篇
  2000年   4篇
  1999年   4篇
  1997年   2篇
  1996年   2篇
  1995年   2篇
  1993年   1篇
  1991年   1篇
  1990年   1篇
  1983年   1篇
排序方式: 共有186条查询结果,搜索用时 687 毫秒
81.
Effective conservation management interventions must combat threats and deliver benefits at costs that can be achieved within limited budgets. Considerable effort has focused on measuring the potential benefits of conservation interventions, but explicit quantification of the financial costs of implementation is rare. Even when costs have been quantified, haphazard and inconsistent reporting means published values are difficult to interpret. This reporting deficiency hinders progress toward a collective understanding of the financial costs of management interventions across projects and thus limits the ability to identify efficient solutions to conservation problems or attract adequate funding. We devised a standardized approach to describing financial costs reported for conservation interventions. The standards call for researchers and practitioners to describe the objective and outcome, context and methods, and scale of costed interventions, and to state which categories of costs are included and the currency and date for reported costs. These standards aim to provide enough contextual information that readers and future users can interpret the cost data appropriately. We suggest these standards be adopted by major conservation organizations, conservation science institutions, and journals so that cost reporting is comparable among studies. This would support shared learning and enhance the ability to identify and perform cost‐effective conservation.  相似文献   
82.
The Adriatic and Ionian Region is an important area for both strategic maritime development and biodiversity conservation in the European Union (EU). However, given that both EU and non‐EU countries border the sea, multiple legal and regulatory frameworks operate at different scales, which can hinder the coordinated long‐term sustainable development of the region. Transboundary marine spatial planning can help overcome these challenges by building consensus on planning objectives and making the trade‐offs between biodiversity conservation and its influence on economically important sectors more explicit. We address this challenge by developing and testing 4 spatial prioritization strategies with the decision‐support tool Marxan, which meets targets for biodiversity conservation while minimizing impacts to users. We evaluated these strategies in terms of how priority areas shift under different scales of target setting (e.g., regional vs. country level). We also examined the trade‐off between cost‐efficiency and how equally solutions represent countries and maritime industries (n = 14) operating in the region with the protection‐equality metric. We found negligible differences in where priority conservation areas were located when we set targets for biodiversity at the regional versus country scale. Conversely, the prospective impacts on industries, when considered as costs to be minimized, were highly divergent across scenarios and biased the placement of protection toward industries located in isolation or where there were few other industries. We recommend underpinning future marine spatial planning efforts in the region through identification of areas of national significance, transboundary areas requiring cooperation between countries, and areas where impacts on maritime industries require careful consideration of the trade‐off between biodiversity conservation and socioeconomic objectives.  相似文献   
83.
Limited knowledge of dispersal for most organisms hampers effective connectivity conservation in fragmented landscapes. In forest ecosystems, deadwood‐dependent organisms (i.e., saproxylics) are negatively affected by forest management and degradation globally. We reviewed empirically established dispersal ecology of saproxylic insects and fungi. We focused on direct studies (e.g., mark‐recapture, radiotelemetry), field experiments, and population genetic analyses. We found 2 somewhat opposite results. Based on direct methods and experiments, dispersal is limited to within a few kilometers, whereas genetic studies showed little genetic structure over tens of kilometers, which indicates long‐distance dispersal. The extent of direct dispersal studies and field experiments was small and thus these studies could not have detected long‐distance dispersal. Particularly for fungi, more studies at management‐relevant scales (1–10 km) are needed. Genetic researchers used outdated markers, investigated few loci, and faced the inherent difficulties of inferring dispersal from genetic population structure. Although there were systematic and species‐specific differences in dispersal ability (fungi are better dispersers than insects), it seems that for both groups colonization and establishment, not dispersal per se, are limiting their occurrence at management‐relevant scales. Because most studies were on forest landscapes in Europe, particularly the boreal region, more data are needed from nonforested landscapes in which fragmentation effects are likely to be more pronounced. Given the potential for long‐distance dispersal and the logical necessity of habitat area being a more fundamental landscape attribute than the spatial arrangement of habitat patches (i.e., connectivity sensu strict), retaining high‐quality deadwood habitat is more important for saproxylic insects and fungi than explicit connectivity conservation in many cases.  相似文献   
84.
The frequently discussed gap between conservation science and practice is manifest in the gap between spatial conservation prioritization plans and their implementation. We analyzed the research‐implementation gap of one zoning case by comparing results of a spatial prioritization analysis aimed at avoiding ecological impact of peat mining in a regional zoning process with the final zoning plan. We examined the relatively complex planning process to determine the gaps among research, zoning, and decision making. We quantified the ecological costs of the differing trade‐offs between ecological and socioeconomic factors included in the different zoning suggestions by comparing the landscape‐level loss of ecological features (species occurrences, habitat area, etc.) between the different solutions for spatial allocation of peat mining. We also discussed with the scientists and planners the reasons for differing zoning suggestions. The implemented plan differed from the scientists suggestion in that its focus was individual ecological features rather than all the ecological features for which there were data; planners and decision makers considered effects of peat mining on areas not included in the prioritization analysis; zoning was not truly seen as a resource‐allocation process and not emphasized in general minimizing ecological losses while satisfying economic needs (peat‐mining potential); and decision makers based their prioritization of sites on site‐level information showing high ecological value and on single legislative factors instead of finding a cost‐effective landscape‐level solution. We believe that if the zoning and decision‐making processes are very complex, then the usefulness of science‐based prioritization tools is likely to be reduced. Nevertheless, we found that high‐end tools were useful in clearly exposing trade‐offs between conservation and resource utilization.  相似文献   
85.
For species at risk of decline or extinction in source–sink systems, sources are an obvious target for habitat protection actions. However, the way in which source habitats are identified and prioritized can reduce the effectiveness of conservation actions. Although sources and sinks are conceptually defined using both demographic and movement criteria, simplifications are often required in systems with limited data. To assess the conservation outcomes of alternative source metrics and resulting prioritizations, we simulated population dynamics and extinction risk for 3 endangered species. Using empirically based habitat population models, we linked habitat maps with measured site‐ or habitat‐specific demographic conditions, movement abilities, and behaviors. We calculated source–sink metrics over a range of periods of data collection and prioritized consistently high‐output sources for conservation. We then tested whether prioritized patches identified the habitats that most affected persistence by removing them and measuring the population response. Conservation decisions based on different source–sink metrics and durations of data collection affected species persistence. Shorter time series obscured the ability of metrics to identify influential habitats, particularly in temporally variable and slowly declining populations. Data‐rich source–sink metrics that included both demography and movement information did not always identify the habitats with the greatest influence on extinction risk. In some declining populations, patch abundance better predicted influential habitats for short‐term regional persistence. Because source–sink metrics (i.e., births minus deaths; births and immigrations minus deaths and emigration) describe net population conditions and cancel out gross population counts, they may not adequately identify influential habitats in declining populations. For many nonequilibrium populations, new metrics that maintain the counts of individual births, deaths, and movement may provide additional insight into habitats that most influence persistence.  相似文献   
86.
对我国出台的15部古树名木保护地方性法规和规章出台时间、主要内容进行了归纳分析。结果发现:法规和规章中存在着管理体制不顺、权责利不对等、处罚标准不合理等问题。在研究基础上,提出完善古树名木保护立法的建议:加快推进古树名木保护国家立法,逐步完善地方立法,进一步理顺保护管理体制,建立古树名木保护补偿制度,加强科学研究与技术推广等。  相似文献   
87.
古河道是一种由形态、物质组成的国土资源,各大江河冲积平原均有分布。利用古河道资源可蒸制灰砂砖,开采泥炭、砂料和地下水,发展旅游产业和多种经营,尤其是在半干旱、半湿润地区利用古河道建设地下水库,调蓄水资源,既可扩大水资源,又能综合治理旱涝碱成。  相似文献   
88.
ABSTRACT: Rome is noted for its water and waste water systems which were constructed during ancient times. This paper is a discussion of the impact these systems had on living conditions in the imperial city. Rome's water system provided a constant supply to centrally located areas in contrast to modern systems which deliver water on demand to individual connections. For both water and waste water systems, access points were generally outside the household. Because of this lack of individual connections, Romans were forced to spend much of their time outside their tenements in the baths, latrines, arenas, streets, and shops of the imperial city.  相似文献   
89.
城墙是城市的重要标志和象征,是一种极具历史文化艺术价值的重要旅游资源,然而古城墙的旅游开发目前还普遍停留在“门票经济”阶段。如何充分认识古城墙的价值,并根据当前旅游市场的需求特征进行深度开发、科学开发和有文化内涵的开发,以临海古城墙为例对上述问题进行了探讨。  相似文献   
90.
古建筑是一个国家重要的历史文化遗产,具有无法估量的艺术价值和科学价值.但是近几年来,我国发生多起古建筑火灾,造成了巨大的损失.由于古建筑结构特殊,极易发生火灾,一旦发生火灾,又很难施救.本文以我国古建筑消防现状为入点,分析古建筑的火灾特点及火灾危险性,提出扑灭古建筑火灾合理的战斗方法及战斗原则,为消防部队灭火提供参考....  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