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   187篇
  免费   10篇
  国内免费   6篇
安全科学   26篇
环保管理   56篇
综合类   62篇
基础理论   27篇
污染及防治   7篇
评价与监测   8篇
社会与环境   8篇
灾害及防治   9篇
  2023年   2篇
  2021年   5篇
  2020年   6篇
  2019年   2篇
  2018年   3篇
  2017年   6篇
  2016年   8篇
  2015年   6篇
  2014年   5篇
  2013年   14篇
  2012年   8篇
  2011年   10篇
  2010年   8篇
  2009年   5篇
  2008年   10篇
  2007年   12篇
  2006年   12篇
  2005年   12篇
  2004年   8篇
  2003年   7篇
  2002年   7篇
  2001年   8篇
  2000年   2篇
  1999年   6篇
  1998年   3篇
  1997年   3篇
  1995年   1篇
  1994年   2篇
  1993年   2篇
  1992年   9篇
  1991年   1篇
  1989年   3篇
  1987年   1篇
  1986年   1篇
  1985年   3篇
  1981年   1篇
  1980年   1篇
排序方式: 共有203条查询结果,搜索用时 15 毫秒
121.
In spite of the widespread recognition of the important roles that small and medium sized enterprises (SMEs) play in most economies, limited research has focused on their impacts on the natural environment and the strategies such enterprises adopt to reduce these impacts. It is usually assumed that SMEs lack the resources to implement proactive environmental strategies that go beyond minimum regulatory compliance. In this study of 108 SMEs in the automotive repair sector in Southern Spain, we found that SMEs undertake a range of environmental strategies from reactive regulatory compliance to proactive pollution prevention and environmental leadership. These strategies are associated with three organizational capabilities: shared vision, stakeholder management, and strategic proactivity, hypothesized based on the unique strategic characteristics of SMEs--shorter lines of communication and closer interaction within the SMEs, the presence of a founder's vision, flexibility in managing external relationships, and an entrepreneurial orientation. We also found that firms with the most proactive practices exhibited a significantly positive financial performance.  相似文献   
122.
Agricultural landscapes illustrate the impact of human actions on physical settings, and differential human pressures cause these landscapes to change with time. Our study explored changes in the terraced landscapes of Nisyros Island, Greece, focusing on the socioeconomic aspects during two time periods using field data, cadastral research, local documents, and published literature, as well as surveys of the islanders. Population increases during the late 19th to early 20th centuries marked a significant escalation of terrace and dry stone wall construction, which facilitated cultivation on 58.4% of the island. By the mid-20th century, the economic collapse of agricultural activities and consequent emigration caused the abandonment of cultivated land and traditional management practices, dramatically reducing farm and field numbers. Terrace abandonment continued in recent decades, with increased livestock grazing becoming the main land management tool; as a result, both farm and pasture sizes increased. Neglect and changing land use has led to deterioration and destruction of many terraces on the island. We discuss the socioeconomic and political backgrounds responsible for the land-use change before World War II (annexation of Nisyros Island by the Ottoman Empire, Italy, and Greece; overseas migration opportunities; and world transportation changes) and after the war (social changes in peasant societies; worldwide changes in agricultural production practices). The adverse landscape changes documented for Nisyros Island appear to be inevitable for modern Mediterranean rural societies, including those on other islands in this region. The island’s unique terraced landscapes may qualify Nisyros to become an archive or repository of old agricultural management techniques to be used by future generations and a living resource for sustainable management.  相似文献   
123.
小城镇基础设施防灾减灾决策支持系统的研究与开发   总被引:15,自引:5,他引:15  
利用信息技术研究灾害问题成为研究热点之一 ,但在小城镇防灾减灾方面仍缺少应有的关注和重视。笔者将地理信息系统 (GIS)和决策支持系统 (DSS)集成应用于开发“基于GIS的小城镇基础设施防灾减灾决策支持系统” ,简要介绍了该系统研制目标和原则、系统结构框架及各子系统的功能 ,解决了系统实现过程中的一系列关键技术 :快速、高效构建小城镇基础空间数据库及三维可视化、应急预案及历史灾情库的电子化及各类灾害分析模拟的专业模型等。实践证明 ,基于基础设施、灾害源、防护保卫目标、应急救援力量的可视化与数字化 ,该系统能够实现对其进行科学管理、对各单一灾种的模拟分析以及应急决策支持 ,有效提高小城镇政府的应急指挥决策水平 ,增强其灾害应急反应能力。  相似文献   
124.
Land surface temperature (LST), which is heavily influenced by urban surface structures, is a significant parameter in urban environmental analysis. This study examined the effect impervious surfaces (IS) spatial patterns have on LST in Beijing, China. A classification and regression tree model (CART) was adopted to estimate IS as a continuous variable using Landsat images from two seasons combined with QuickBird. LST was retrieved from the Landsat Thematic Mapper (TM) image to examine the relationships between IS and LST. The results revealed that CART was capable of consistently predicting LST with acceptable accuracy (correlation coefficient of 0.94 and the average error of 8.59%). Spatial patterns of IS exhibited changing gradients across the various urban-rural transects, with LST values showing a concentric shape that increased as you moved from the outskirts towards the downtown areas. Transect analysis also indicated that the changes in both IS and LST patterns were similar at various resolution levels, which suggests a distinct linear relationship between them. Results of correlation analysis further showed that IS tended to be positively correlated with LST, and that the correlation coefficients increased from 0.807 to 0.925 with increases in IS pixel size. The findings identified in this study provide a theoretical basis for improving urban planning efforts to lessen urban temperatures and thus dampen urban heat island effects.  相似文献   
125.
以2007年长岛县海岛调查资料为基础,分析了长岛县海岛潮间带沉积物中重金属含量特征及其与有机质含量等之间的相关关系,并对其潜在生态危害进行了评价。结果表明,所有海岛潮间带重金属元素含量均未超过环境背景值;不同海岛间潮间带沉积物中重金属元素与有机质的关系略有差异;长岛县海岛潮间带重金属具有轻微生态危险,该海区可适当发展养殖业和旅游业。  相似文献   
126.
The Galapagos Archipelago (Ecuador) is one of the most well-known natural sites in the world for its unique biodiversity. This sensitive ecosystem is at risk due to a problematic equilibrium between its conservation policy and development demand. To contribute to implementing integrated sustainable resource management in the Galapagos Islands, a material flow analysis (MFA) of Santa Cruz – the island with the highest anthropic pressure in the archipelago – has been performed, outlining a quantitative and qualitative assessment of the direct flow of goods throughout the system. MFA outcomes have been used to evaluate and forecast the impact of some policies and strategies on the local system, focusing in particular on fossil fuel consumption and local agricultural production. This case study stresses the need to introduce a local MFA protocol to decision-makers’ toolbox, as it provides quantitative assessments on a broad spectrum of local development issues.  相似文献   
127.
随着近几年中小城市发展进程的加快,城市中日益暴露出各方面的问题与弊端,污水治理问题显得尤为突出和严重。污水排放大量增加对我国中小城市水环境造成了严重的污染和破坏,因此对污水处理技术的选择与考量十分迫切。基于我国国情,我国是发展中国家,财力有限。因此用于基础设施上的资金在大城市和中小城镇之间的分配比重严重失衡,中小城镇污水的处理率相对较低。这就决定了中小城镇在选择污水处理技术时,首先要考虑的因素必须是经济、高效、节能和简便易行。  相似文献   
128.
结合小城镇环境生态区域广、生态类型多样且生态敏感度高等特点,采用DPSIR模式选取指标,建立了小城镇工业园区环境影响评价指标体系,在与城市工业园区比较、园区周围存在的农村生态系统方面提出增加资源能源利用、控制污染物排放的建议。  相似文献   
129.
130.
This short note discusses methodological obstacles to the collection of microeconomic data in artisanal and small-scale mining communities. International donor organizations are supporting policy efforts that enhance the contribution to poverty alleviation of this mining subsector. The design and evaluation of such policy interventions require data on income, expenditure, investment, and savings in mining households and communities. These data are difficult to come by. Incomes are variable; migrants may work far from home; miners often work informally and sometimes illegally; mining populations and communities are heterogeneous and transient; and miners have many reasons to distort information. Legalization and organization of miners in cooperatives would facilitate documentation and research. These processes, however, are beyond the control of the typical policy consultant or donor organization. On their part, these parties can adopt an alternative model of research. This model involves the community in project development, data collection, and monitoring. It emphasizes continuity, cultural diversity, trust building and learning. The data thus collected should provide a firm basis for programmes that promote more sustainable livelihoods in artisanal and small-scale mining communities.  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