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   442篇
  免费   25篇
  国内免费   26篇
安全科学   38篇
废物处理   1篇
环保管理   92篇
综合类   126篇
基础理论   60篇
环境理论   4篇
污染及防治   13篇
评价与监测   8篇
社会与环境   21篇
灾害及防治   130篇
  2023年   8篇
  2022年   11篇
  2021年   17篇
  2020年   17篇
  2019年   17篇
  2018年   19篇
  2017年   15篇
  2016年   26篇
  2015年   26篇
  2014年   9篇
  2013年   33篇
  2012年   16篇
  2011年   23篇
  2010年   23篇
  2009年   20篇
  2008年   13篇
  2007年   23篇
  2006年   28篇
  2005年   21篇
  2004年   12篇
  2003年   17篇
  2002年   15篇
  2001年   13篇
  2000年   18篇
  1999年   13篇
  1998年   3篇
  1997年   5篇
  1996年   6篇
  1995年   6篇
  1994年   7篇
  1992年   3篇
  1991年   2篇
  1990年   1篇
  1987年   2篇
  1984年   1篇
  1983年   2篇
  1981年   1篇
  1980年   1篇
排序方式: 共有493条查询结果,搜索用时 252 毫秒
351.
This paper describes an applied research project that used a sustainable land-use planning approach to examine flood hazard mitigation alternatives in a 536-acre developed office park complex. A watershed-wide assessment including floodplain remapping and modelling of low-impact and large stormwater improvements throughout the upper watershed revealed limited impact on reducing flooding downstream in the environs of the office park during large storms. Thus emphasis had to be given to recommending retroactive sustainable land-use development actions such as relocating buildings and roadways out of the 100-year floodplain, which involves creating a mixed-use overlay district on high elevations, and restoring the floodplain.  相似文献   
352.
A 3D marine seismic survey of the Odoptu license area off northeastern Sakhalin Island, Russia, was conducted by DalMorNefteGeofizika (DMNG) on behalf of Exxon Neftegas Limited and the Sakhalin-1 consortium during mid-August through early September 2001. The key environmental issue identified in an environmental impact assessment was protection of the critically endangered western gray whale (Eschrichtius robustus), which spends the summer–fall open water period feeding off northeast Sakhalin Island in close proximity to the seismic survey area. Seismic mitigation and monitoring guidelines and recommendations were developed and implemented to reduce impacts on the feeding activity of western gray whales. Results of the acoustic monitoring program indicated that the noise monitoring and mitigation program was successful in reducing exposure of feeding western gray whales to seismic noise.  相似文献   
353.
温室气体减排项目评价方法研究   总被引:8,自引:0,他引:8  
阐述了温室气体减排技术选择的准则与优先领域,以及温室气体减排项目评价应包括的主要内容;对3类主要的温室气体减排项目——节能技术改造项目、新建提高能源转换或利用效率项目及能源替代项目,分别探讨了基准线的确定方法、减排量和增量减排成本的计算方法在这3个项目评价中的难点;介绍了温室气体间接减排项目评价方法;最后以张北风电场二期风电项目为例对全球环境效益进行评价。   相似文献   
354.
基于能力谱的建筑物震害评估及城市抗震规划   总被引:2,自引:1,他引:1  
为减轻地震建筑物破坏带来的人员伤亡和经济损失,根据能力谱方法计算7度和8度地震影响下建筑物的破坏状态,在此基础上进行城市抗震规划。首先把城市建筑物分成钢筋混凝土、砌体、钢框架及木结构4类;然后利用能力谱方法得到建筑物各种损坏状态的概率及震害指数;最后提出抗震规划措施,在GIS环境下可视化表达建筑物震害分级图。结果表明,中层小于低层和高层建筑物的震害指数;对低层和中层建筑物,钢筋混凝土的抗震能力较强。7度地震时,未设防和低设防建筑物的震害指数在0.5和1.0之间,轻微破坏;部分中等设防和高设防建筑物的震害指数小于0.5,基本完好。8度地震时,4类建筑物的震害指数在0.5~1.0之间,轻微破坏。进行城市抗震规划后,建筑物受7度地震影响时基本完好,受8度地震影响时轻微破坏。  相似文献   
355.
通过对灾后重建规划的反思,强调坚持安全第一的灾后重建选址原则,强化灾害评估机制的程序,提倡坚持科学发展观,树立与自然和谐共生的规划理念;针对我国人地矛盾突出的特点,提出了城镇发展要规模适度及实施迁村并点的具体措施等预防和减轻灾害的规划途径;并提出了建设高效的应急体系,以应对超标准自然灾害的建议。  相似文献   
356.
洪水风险分析的研究进展与展望   总被引:9,自引:2,他引:7  
我国洪涝灾害频繁,损失极大,引人注目。洪水的风险分析工作是实施非工程措施,从而科学有效地防洪减灾的前提和基础。在概括系统风险定义和来源的基础上,对洪水风险分析的研究现状作了评述。洪水风险分析的研究方法已从直接积分法、蒙特卡罗法、均值一次两阶矩法,发展到改进一次两阶矩法、二次矩法和JC法等。综述了洪水风险分析的研究成果,同时建议:(1)明确并统一风险分析的内涵;(2)开展“风险分析的风险”的研究;(3)将熵理论引入到风险分析之中;(4)拓展风险分析的基本理论和研究方法,如应用模糊信息优化处理技术、灰色系统、未确知数学等。  相似文献   
357.
Evaluating the outcomes and tracking the trajectory of biodiversity offsets is essential to demonstrating their effectiveness as a mechanism to conciliate development and conservation. We reviewed the literature to determine the principles that should underpin biodiversity offset planning and the criteria for offset evaluation at the project level. According to the literature, the core principles of equivalence, additionality, and permanence are used as criteria to evaluate conservation outcomes of offsets. We applied the criteria to evaluate offsets of a large iron ore mining project in the Atlantic Forest in Brazil. We examined equivalence in terms of the amount of area per biodiversity value affected and fauna and flora similarity, additionality in terms of landscape connectivity, and permanence in terms of guarantees to ensure protection and restoration offsets lasting outcomes. We found an offset ratio (amount of affected area:offset area) of 1:1.8 for forests and 1:2 for grasslands. Ecological equivalence (i.e., similarity between affected and offset areas) was found for forested areas, but not for ferruginous rupestrian grasslands or for fauna. Landscape metrics showed that connectivity improved relative to the preproject situation as a result of locating restoration offsets in the largest and best-connected forest patch. Permanence of offsets was addressed by establishing covenants and management measures, but financial guarantees to cover maintenance costs after mine closure were lacking. Offsets should be equivalent in type and size, provide conservation outcomes that would not be obtained without them (additionality), and be lasting (permanence). To monitor and evaluate offsets, it is necessary to determine how well these 3 principles are applied in the planning, implementation, and maintenance of offsets. Achieving measurable conservation outcomes from offsets is a long-term endeavor that requires sustained management support, and is information intensive. Thus, offsets require ongoing monitoring and evaluation as well as adaptive management.  相似文献   
358.
359.
ABSTRACT

Land science has generated critical knowledge about how humans modify Earth’s surface and has advanced our understanding of land as a coupled human–environment system. However, to date, most work has been in frontier environments with less attention – both conceptually and empirically – on how urban land systems affect the carbon cycle. Much of what is known about urban areas and the carbon cycle is limited to aggregate levels of activities within urban areas, usually by sector, with little focus on how the spatial configuration of urban land systems affects carbon-emitting activities. Given that urban areas produce about 70% of global energy-related CO2 emissions, it is crucial to understand the relationship between urban environments, the activities they influence, and the resulting carbon emissions. This paper summarizes the current state of knowledge of how urban land systems affect carbon emissions and vulnerability, and identifies research gaps and opportunities for urban land science to contribute to climate change science, particularly through land architecture. We argue that more attention to urban land science conceptualization, measurement, and analysis would contribute to both fundamental knowledge about urban systems, as well as help identify policies and strategies for mitigation and adaptation to climate change at the urban scale.  相似文献   
360.
采用室内模拟的方法,研究了两种基因型水稻(硅突变体和野生型)根系吸收As的动力学特征以及Si对水稻吸收As的影响.结果表明,两种基因型水稻根系对As(III)和As(V)的吸收均可以用Freundlich模型较好地模拟.外源Si的加入可显著降低水稻根系对As(III)和As(V)的吸收.在20μmol·L-1As处理下,与不加Si处理相比,加1.0mmol·L-1Si处理导致水稻根系吸收As(III)和As(V)分别降低94.1%和92.2%(野生型);74.4%和90.2%(突变体).在100μmol·L-1As处理下,水稻根系吸收As(III)和As(V)则分别降低64.5%和91.2%(野生型);76.1%和90.6%(突变体).  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