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   89篇
  免费   4篇
  国内免费   6篇
安全科学   8篇
环保管理   20篇
综合类   34篇
基础理论   24篇
污染及防治   6篇
评价与监测   2篇
社会与环境   5篇
  2023年   1篇
  2022年   2篇
  2021年   2篇
  2020年   5篇
  2019年   2篇
  2018年   2篇
  2017年   4篇
  2016年   9篇
  2015年   4篇
  2014年   1篇
  2013年   3篇
  2012年   4篇
  2011年   1篇
  2010年   4篇
  2009年   8篇
  2008年   10篇
  2007年   5篇
  2006年   4篇
  2005年   2篇
  2004年   1篇
  2003年   1篇
  2002年   1篇
  2001年   2篇
  2000年   3篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1994年   2篇
  1992年   2篇
  1990年   1篇
  1989年   2篇
  1987年   1篇
  1986年   1篇
  1980年   1篇
  1979年   1篇
  1972年   1篇
  1970年   1篇
排序方式: 共有99条查询结果,搜索用时 176 毫秒
91.
Ecosystem services support human livelihoods and economies but are declining in many places. Ecosystem service assessments estimate the benefits that nature provides to people and can be used to evaluate trade-offs in impacts and changes resulting from land use decisions. Such assessments can affect the capacity of decision-makers to make sustainable land use decisions, but the actual impact of such projects on decision-maker attitudes is almost entirely unstudied. We addressed this knowledge gap by evaluating the impact of an ecosystem service assessment on decision-makers in California. We asked how decision-makers’ understanding of and attitudes about ecosystem services changed “pre-” and “post-” assessments and between treatment groups where ecosystem services were assessed and a comparison group where ecosystem services were not assessed. Mixed methods included regression models to estimate the treatment effect of the assessment (using a difference-in-differences approach), as well as interviews and direct observations to further understand how decision-makers responded to the assessment. Regression results showed small increases relative to the comparison group in decision-maker understanding of ecosystem services and perceived relevance of ecosystem services to their work. Interviews confirmed that decision-makers learned specific ways that they could use ecosystem services in conservation and development decisions and believed that doing so would improve outcomes. These results demonstrate how ecosystem services assessments can facilitate a conceptual shift in the minds of decision-makers, which is a necessary ingredient for subsequent policy impact. Impact evaluation studies of this type − that estimate a counterfactual and explore rival explanations for observed outcomes − are needed to truly understand whether ecosystem service projects impact decision-makers and, ultimately, produce outcomes for environmental and human well-being.  相似文献   
92.
Impact of consistent boundary layer mixing approaches between NAM and CMAQ   总被引:1,自引:0,他引:1  
Discrepancies in grid structure, dynamics and physics packages in the offline coupled NWS/NCEP NAM meteorological model with the U.S. Environmental Protection Agency Community Multiscale Air Quality (CMAQ) model can give rise to inconsistencies. This study investigates the use of three vertical mixing schemes to drive chemistry tracers in the National Air Quality Forecast Capability (NAQFC). The three schemes evaluated in this study represent various degrees of coupling to improve the commonality in turbulence parameterization between the meteorological and chemistry models. The methods tested include: (1) using NAM predicted TKE-based planetary boundary height, h, as the prime parameter to derive CMAQ vertical diffusivity; (2) using the NAM mixed layer depth to determine h and then proceeding as in (1); and (3) using NAM predicted vertical diffusivity directly to parameterize turbulence mixing within CMAQ. A two week period with elevated surface O3 concentrations during the summer 2006 has been selected to test these schemes in a sensitivity study. The study results are verified and evaluated using the EPA AIRNow monitoring network and other ozonesonde data. The third method is preferred a priori as it represents the tightest coupling option studied in this work for turbulent mixing processes between the meteorological and air quality models. It was found to accurately reproduce the upper bounds of turbulent mixing and provide the best agreement between predicted h and ozonesonde observed relative humidity profile inferred h for sites investigated in this study. However, this did not translate into the best agreement in surface O3 concentrations. Overall verification results during the test period of two weeks in August 2006, did not show superiority of this method over the other 2 methods in all regions of the continental U.S. Further efforts in model improvement for the parameterizations of turbulent mixing and other surface O3 forecast related processes are warranted.  相似文献   
93.
A sensitivity study is performed to examine the impact of lateral boundary conditions (LBCs) on the NOAA-EPA operational Air Quality Forecast Guidance over continental USA. We examined six LBCS: the fixed profile LBC, three global LBCs, and two ozonesonde LBCs for summer 2006. The simulated results from these six runs are compared to IONS ozonesonde and surface ozone measurements from August 1 to 5, 2006. The choice of LBCs can affect the ozone prediction throughout the domain, and mainly influence the predictions in upper altitude or near inflow boundaries, such as the US west coast and the northern border. Statistical results shows that the use of global model predictions for LBCs could improve the correlation coefficients of surface ozone prediction over the US west coast, but could also increase the ozone mean bias in most regions of the domain depending on global models. In this study, the use of the MOZART (Model for Ozone And Related chemical Tracers) prediction for CMAQ (Community Multiscale Air Quality) LBC shows a better surface ozone prediction than that with fixed LBC, especially over the US west coast. The LBCs derived from ozonesonde measurements yielded better O3 correlations in the upper troposphere.  相似文献   
94.
Atmospheric models are essential tools to study the behavior of air pollutants. To interpret the complicated atmospheric model simulations, a new-generation Model Visualization and Analysis Tool (Model-VAT) has been developed for scientists to analyze the model data and visualize the simulation results. The Model-VAT incorporates analytic functions of conventional tools and enhanced capabilities in flexibly accessing, analyzing, and comparing simulated results from multi-scale models with different map projections and grid resolutions. The performance of the Model-VAT is demonstrated by a case study of investigating the influence of boundary conditions (BCs) on the ambient Hg formation and transport simulated by the CMAQ model over the Pearl River Delta (PRD) region. The alternative BC options are taken from (1) default time-independent profiles, (2) outputs from a CMAQ simulation of a larger nesting domain, and (3) concentration files from GEOS-Chem (re-gridded and re-projected using the Model-VAT). The three BC inputs and simulated ambient concentrations and deposition were compared using the Model-VAT. The results show that the model simulations based on the static BCs (default profile) underestimates the Hg concentrations by ~6.5%, dry depositions by ~9.4%, and wet depositions by ~43.2% compared to those of the model-derived (e. g. GEOS-Chem or nesting CMAQ) BCs. This study highlights the importance of model nesting approach and demonstrates that the innovative functions of Model-VAT enhances the efficiency of analyzing and comparing the model results from various atmospheric model simulations.
  相似文献   
95.
We present a method for detecting the zones where an irregularly sampled variable changes abruptly in the plane. Such zones are called Zones of Abrupt Change (ZACs). This method not only allows estimation of ZACs, but also testing of their statistical significance against the null hypothesis of a stationary correlated random field. The sampling pattern, in particular its local density, is crucial in the detection of potential ZACs. In this paper, we address the problem of evaluating the sampling pattern by assessing the power of the local test used for detecting ZACs. It is shown that mapping the power allows us to identify zones where ZACs may or may not be detected. The methodology is applied to a soil data set sampled at eight different dates in an agricultural field. Detecting ZACs for the soil water content allowed us to identify permanent structures in the agricultural field related to the boundaries between different soil types. Mapping the power for various sampling densities proved to be useful to determine the minimal sampling density necessary for detecting ZACs.
Edith GabrielEmail:
  相似文献   
96.
在对定向广告影响低碳产品制造商、零售商的供应链营销投资策略及其竞争关系分析基本上,建立制造商主导的Stackelberg博弈模型,给出制造商、零售商不同投资策略组合下的支付矩阵,构建以促进低碳产品销售为目标的演化博弈模型,根据产品低碳度、差异化低碳产品,分析不同低碳产品供应链定向广告投资策略演化路径及稳定性,并利用Netlogo进行博弈双方策略演化仿真,揭示消费者低碳偏好度、广告效应因子、价格敏感系数对策略演化路径的影响规律.研究发现,在制造商、零售商有限理性下,成本共担契约不能促成双方定向广告投资合作;产品低碳度不同,低碳供应链演化均衡策略存在差异;与制造商相比,零售商投资定向广告可催生更大市场需求,更有利于低碳产品的普及和推广;对低碳度较高产品,消费者低碳偏好度、价格敏感系数与零售商投资意愿正相关,广告效应因子对零售商投资意愿的影响存在峰值,当广告效应因子在合适范围内时,零售商投资意愿最大.据此,提出了相应的管理启示和决策建议.  相似文献   
97.
Implementing Participatory Decision Making in Forest Planning   总被引:2,自引:0,他引:2  
Forest policy decisions are often a source of debate, conflict, and tension in many countries. The debate over forest land-use decisions often hinges on disagreements about societal values related to forest resource use. Disagreements on social value positions are fought out repeatedly at local, regional, national, and international levels at an enormous social cost. Forest policy problems have some inherent characteristics that make them more difficult to deal with. On the one hand, forest policy decisions involve uncertainty, long time scales, and complex natural systems and processes. On the other hand, such decisions encompass social, political, and cultural systems that are evolving in response to forces such as globalization. Until recently, forest policy was heavily influenced by the scientific community and various economic models of optimal resource use. However, growing environmental awareness and acceptance of participatory democracy models in policy formulation have forced the public authorities to introduce new participatory mechanisms to manage forest resources. Most often, the efforts to include the public in policy formulation can be described using the lower rungs of Arnstein’s public participation typology. This paper presents an approach that incorporates stakeholder preferences into forest land-use policy using the Analytic Hierarchy Process (AHP). An illustrative case of regional forest-policy formulation in Australia is used to demonstrate the approach. It is contended that applying the AHP in the policy process could considerably enhance the transparency of participatory process and public acceptance of policy decisions.  相似文献   
98.
以民主村断面上游为研究对象,利用有机物非靶向筛查技术,结合现场快速筛查、实验室分析及现场实地勘查结果,判断重点监测区域污染情况,并使用卫星遥感、无人机及现场排查对民主村断面所在的兴盐界河开展全流域排查。结果表明,兴盐界河沿线排污口众多,民主村断面汇水区域及兴盐界河沿线广泛受到养殖业、生活源、种植业污染,河内源污染严重,加之水流不畅、汛期放大污染等自然因素,导致断面水质无法稳定达标,全年平均水质超Ⅲ类。  相似文献   
99.
“甜甜圈”理论是行星边界可持续发展评估体系中不可或缺的一部分。在原有的15个社会经济系统评估维度的基础上,针对不同研究样本概括了每个维度对应的具体指标,并总结了指标阈值设定的方法,包括惯例的延续、经验的借鉴以及典型样本的参考等。在此基础上,利用统计年鉴和中国综合社会调查(CGSS)数据,创新性地将“十二五”规划文件中相关指标的预期值设定为阈值,揭示了中国在收入水平和工作机会方面已达到最优状态,贫困问题得到了一定程度的解决,但水资源和能耗方面表现不佳;中国南部地区“自西向东”可持续发展程度越来越高,中国北部则是“自北往南”。社会经济系统需要在内容的丰富、理论的深化和阈值的客观设定等方面进一步完善。  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