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   1663篇
  免费   150篇
  国内免费   252篇
安全科学   48篇
废物处理   8篇
环保管理   351篇
综合类   831篇
基础理论   398篇
环境理论   1篇
污染及防治   48篇
评价与监测   101篇
社会与环境   185篇
灾害及防治   94篇
  2024年   6篇
  2023年   31篇
  2022年   64篇
  2021年   88篇
  2020年   59篇
  2019年   67篇
  2018年   50篇
  2017年   69篇
  2016年   97篇
  2015年   76篇
  2014年   94篇
  2013年   131篇
  2012年   111篇
  2011年   131篇
  2010年   113篇
  2009年   81篇
  2008年   73篇
  2007年   99篇
  2006年   95篇
  2005年   81篇
  2004年   56篇
  2003年   70篇
  2002年   41篇
  2001年   28篇
  2000年   43篇
  1999年   34篇
  1998年   26篇
  1997年   21篇
  1996年   29篇
  1995年   15篇
  1994年   18篇
  1993年   15篇
  1992年   7篇
  1991年   8篇
  1990年   3篇
  1989年   8篇
  1988年   7篇
  1987年   2篇
  1986年   1篇
  1984年   1篇
  1983年   1篇
  1980年   2篇
  1978年   2篇
  1977年   5篇
  1975年   2篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
  1971年   1篇
排序方式: 共有2065条查询结果,搜索用时 140 毫秒
61.
阐述了旅游区域联动发展战略的内涵、类型、原则及意义,分析了安徽省"两山一湖"地区实施旅游区域联动战略的必要性、可能性和发展现状,提出了若干对策.  相似文献   
62.
Conflicts between industrial development and environmental conservation can be particularly acute when such development occurs in the vicinity of World Heritage sites. A key example is the Great Barrier Reef World Heritage Area (GBRWHA) in northeastern Australia, where a 2012 review by the World Heritage Council found that rapid port development inshore of the coral reef posed significant risks to local marine ecosystems. Such instances pose pressing challenges for decision‐makers seeking to manage World Heritage sites for multiple values and needs, including those of key stakeholder groups, such as local communities. There is increasingly a societal expectation that public decision‐making takes into account local views and priorities, and that companies seek a ‘social license to operate’. This research explored local community attitudes toward port development associated with the export of liquefied natural gas (LNG) and coal through the GBRWHA. Using data drawn from a survey and interviews, the research examined how a range of geographical factors, including proximity to gas infrastructure and the perceived impacts and risks of development to the local community, economy and environment shape community perceptions of the industry. Findings suggest that local attitudes toward gas and coal terminal development inshore of the GBRWHA are shaped predominantly by community perceptions of environmental impacts and risks associated with such infrastructure, in contrast to a broader public narrative that focuses largely on economic benefits. A complex combination of other factors, including social impacts, personal environmental values, community trust in industry, and equity in decision‐making and distribution of the risks and benefits of industrial development also contribute. Placed in a broader, global context, the findings have important implications for public decision‐making processes in Australia and elsewhere as they suggest that, for local communities, the perceived impacts of gas development on the environment may overshadow the benefits of industry.  相似文献   
63.
PM10作为大气污染物监测的主要指标之一,探究大气PM10浓度对大气环境质量和人体健康评价具有重要意义。黄、渤海滨海带包括京、津和辽、冀、鲁、苏等工、农业大省,区域大气PM10污染的时空分布和来源特征具有复杂性和典型性。在锦州、北京、天津、烟台、青岛、连云港和盐城7个城市布设10个采样点,含7个城市点和3个农村点,开展为期一年的大气颗粒物的采样;同时,于冬季1月和夏季7月在锦州、天津和烟台进行合计60 d的加密采样,藉以确定研究区域大气PM10的时空分布和来源特征。结果表明,黄、渤海滨海带大气年均PM10总浓度为(129’18)"g·m~(-3),单月最低值出现在2015年7月盐城农村样点15"g·m~(-3),最高值为2015年3月北京城市点307"g·m~(-3)。盐城大气PM10浓度(城市点(85’27)"g·m~(-3)和农村点(66’35)"g·m~(-3))显著低于其他样点大气PM10浓度。渤海滨海带中西部的京(140’68"g·m~(-3))、津(169’60"g·m~(-3))两市大气PM10年均浓度显著高于东部的锦州(125’41"g·m~(-3))和烟台(109’31"g·m~(-3));而且黄海滨海带大气PM10年均浓度(114"g·m~(-3))显著低于渤海滨海带年均浓度(136"g·m~(-3)),总体上表现出西高东低、北高南低的特征。黄、渤海滨海带城市点和农村点年均浓度分别为(129’18)"g·m~(-3)和(112’30)"g·m~(-3);农村点春冬季大气PM10浓度和城市点浓度相当,无显著差异,夏秋季大气PM10浓度略低于城市浓度,表明农村地区大气颗粒物污染情况也较为严重,需受到关注。区域内PM10浓度季节变化整体表现为春冬高、夏秋低。利用多元回归分析初步判断黄、渤海滨海带PM10属于复合来源,大气PM10浓度约30%的变化与降水、人均能耗和沙尘天气相关。黄、渤海滨海带大气PM10浓度的昼夜变化不大,大气PM10浓度与气温呈现正相关,与风速和降水呈现负相关,表现为受各种气象因素综合作用的影响。  相似文献   
64.
Climate change represents one of the most pressing societal and scientific challenges of our time. While much of the current research on climate change focuses on future prediction, some of the strongest signals of warming can already be seen in Arctic and alpine areas, where temperatures are rising faster than the global average, and in the oceans, where the combination of rising temperatures and acidification due to increased CO2 concentrations has had catastrophic consequences for sensitive marine organisms inhabiting coral reefs. The scientific papers highlighted as part of this anniversary issue represent some of the most impactful advances in our understanding of the consequences of anthropogenic climate change. Here, we reflect on the legacy of these papers from the biotic perspective.  相似文献   
65.
Theoretical articles linking conservation and welfare find a negative relationship between these two variables while empirical studies show that land protection may be positively related to welfare. Several authors attribute this empirical result to the development of ecotourism in protected areas. We thus argue that the gap between the theory and existing empirical results is partly explained by the fact that most theoretical models do not account for a productive activity on protected land. Therefore, we develop a theoretical model in which conservation allows developing an alternative sector and show that the relationship between conservation and welfare is U-shaped. We test this theoretical prediction using Nepalese data and find that conservation combined with ecotourism is indeed positively related to local welfare.  相似文献   
66.
为满足《水污染防治行动计划》近岸海域水质考核要求,根据目前近岸海域环境监测工作的实际情况,在考核范围、评价方法、目标分解、计分方法等方面进行了比较,在保证公平、公正的前提下,以一致性、可比性和适应性为原则,提出的考核评价方法以单因子评价法和点位评价法为基础,在未达标情况下,按照水质目标完成比例计分;达标情况下,在达标分值基础上按水质的保持和改善给予不同程度的加分,通过实例研究分析能够适应近岸海域水质状况变化的考核工作要求。  相似文献   
67.
Eight stormwater user fees (SUFs) were applied to the City of Roanoke and the Town of Blacksburg, Virginia, to determine the effect each has on how land use type impacts the sources of revenue. Roanoke is larger and includes more industrial areas, but less multifamily impervious areas than Blacksburg, which translates differently in the SUFs. Residential parcels comprise the highest percentage of the revenue in all eight SUFs in Blacksburg and four in Roanoke. For both municipalities, two specific SUFs consistently comprised the highest percentage burden for residential homeowners while three other SUFs demonstrated the highest burden for commercial parcels. Open space parcels contain little impervious area, yet account for up to 27% of the revenue in the Blacksburg Area fee structure. Industrial parcels comprise more revenue in Roanoke, averaging 10.1‐4.5% in Blacksburg. Fee types that are easier to administer (e.g., Flat fees) may not fully represent the stormwater contribution from the parcels. SUF types that more accurately represent the stormwater burden on the municipality are also more administratively intensive and are more variable with fee factors.  相似文献   
68.
Trace element concentrations were studied in soils of the King George and Elephant islands in the maritime part of West Antarctica. The lowest concentrations of Cu, Pb, Cd, Zn, Ni and Mn were typical for the pristine soil of Elephant Island. The highest concentrations of these elements were found in the Fildes Peninsula and revealed the influence of human activities in the area of the Bellingshausen station and adjacent waste disposal sites. Ornithogenic soils of the Fildes Peninsula have shown low concentrations of Cd and As. Using geoaccumulation indexes, all the pristine soils of King George and Elephant islands and ornithogenic soils of the Fildes Peninsula were classified as unpolluted; the human-affected soils were mainly identified as moderately polluted. Obtained data can be used as background concentration levels for further researches.  相似文献   
69.
围垦后南汇东滩海三棱藨草的空间分布及其影响因子研究   总被引:3,自引:0,他引:3  
2015年9月~10月期间对2012年底围垦后南汇嘴区域的海三棱藨草(Scirpus mariqueter)湿地系统进行了调研,运用主成分分析、典范对应分析(canonical correspondence analysis,CCA)方法,基于101个样地土壤的有机碳、总磷、总氮、硝酸盐氮、亚硝酸盐氮、氨氮、正磷酸盐、pH、含水率、粒径、盐度、滩涂高程等12个环境因子数据,探讨了围垦后海三棱藨草空间分布的关键影响因子。结果表明:海三棱藨草的分布与滩涂高程具有显著正相关(P0.05),海三棱藨草群落主要分布在南汇滩涂2.5~3.4 m高程范围内;海三棱藨草的密度、盖度与盐度呈显著正相关(P0.05)。结论认为滩涂高程和土壤盐度是影响海三棱藨草分布的主要环境因子。未来需要结合围垦后的水动力变化过程数值模拟,对海三棱藨草生态系统高时空分辨率的响应过程及机制进行研究,以进一步确立海三棱藨草对围垦工程响应的关键阈值。研究对围垦工程后的滨海湿地植被恢复及滩涂生态修复具有参考意义。  相似文献   
70.
Urban stormwater practices are individually diverse, but they are components of an overall urban watershed system. This study proposes a conceptual model of that system, including its component spatial areas, their arrangement along the flow route, and their associations with urban land uses and values. The model defines three spatial areas along the flow route which have evolved over time into their present forms: (1) the source area, which is arranged and furnished primarily or entirely for human use, accommodation, and comfort; (2) the perimeter area, where specialized stormwater facilities carry away source‐area runoff or buffer downstream areas from its impacts; and (3) the downstream area, which receives the discharges from the perimeter or directly from the source area. Each area presents a specific combination of stormwater features and human interactions, and excludes others. Considering stormwater flows and functions in the context of physical urban spaces brings into view the spaces’ urban structures and interacting agendas. This model allows practitioners to navigate conceptually through the system, and to focus appropriate objectives and structures on each project site.  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