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   692篇
  免费   118篇
  国内免费   79篇
安全科学   259篇
废物处理   7篇
环保管理   167篇
综合类   247篇
基础理论   78篇
环境理论   5篇
污染及防治   14篇
评价与监测   26篇
社会与环境   49篇
灾害及防治   37篇
  2024年   1篇
  2023年   16篇
  2022年   18篇
  2021年   27篇
  2020年   28篇
  2019年   35篇
  2018年   28篇
  2017年   50篇
  2016年   44篇
  2015年   43篇
  2014年   40篇
  2013年   46篇
  2012年   56篇
  2011年   66篇
  2010年   44篇
  2009年   52篇
  2008年   26篇
  2007年   54篇
  2006年   43篇
  2005年   27篇
  2004年   24篇
  2003年   16篇
  2002年   14篇
  2001年   12篇
  2000年   12篇
  1999年   11篇
  1998年   8篇
  1997年   9篇
  1996年   6篇
  1995年   9篇
  1994年   7篇
  1993年   7篇
  1992年   7篇
  1989年   1篇
  1983年   1篇
  1972年   1篇
排序方式: 共有889条查询结果,搜索用时 515 毫秒
31.
该文提出了以一个事故工程文件处置、管理一次事故的思想。根据危险化学品事故发生的一般特点和事故处置的一般程序,建立了危险化学平事故应急辅助决策支持软件平台。该软件平台利用GIS技术实现了事故的基本情况、事故初始处置、事故事态发展、现场监测预警等功能,在软件平台的基础上搭配相应的硬件设备组成一套完整的应急辅助决策系统。  相似文献   
32.
General backcasting as a decision support and planning method starts from desired future states and simulates developments backwards until reaching the present state. Development pathways that reveal steps to be taken to reach a certain future state, and milestones that serve as interim goals, are created during the process. Backcasting has hitherto only been applied in workshops or as a theoretical framework and no spatially explicit backcasting model has previously been established. This paper presents the development of a spatially explicit backcasting model. The proposed model first creates a future scenario utilizing an agent-based model and then simulates backwards. It is implemented using the programming language Python. The model has been applied to a case study for sustainable land-use planning in Salzburg, Austria. The results of the model run show a successful backcasting of land-use classes from a future state back to the present, in 10 year time steps.  相似文献   
33.
Nowadays, biodiesel is used as one of the alternative renewable energy due to the increasing energy demand. However, optimum production of biodiesel still requires a huge number of expensive and time-consuming laboratory tests. To address the problem, this research develops a novel Genetic Algorithm-based Evolutionary Support Vector Machine (GA-ESIM). The GA-ESIM is an Artificial Intelligence (AI)-based tool that combines K-means Chaotic Genetic Algorithm (KCGA) and Evolutionary Support Vector Machine Inference Model (ESIM). The ESIM is utilized as a supervised learning technique to establish a highly accurate prediction model between the input--output of biodiesel mixture properties; and the KCGA is used to perform the simulation to obtain the optimum mixture properties based on the prediction model. A real biodiesel experimental data is provided to validate the GA-ESIM performance. Our simulation results demonstrate that the GA-ESIM establishes a prediction model with better accuracy than other AI-based tool and thus obtains the mixture properties with the biodiesel yield of 99.9%, higher than the best experimental data record, 97.4%.  相似文献   
34.
土地城镇化与人口城镇化失调是我国目前城镇化进程中的一个突出问题。但对各地区土地城镇化与人口城镇化的非协调性进行全面系统分析的研究相对较少。此外,鲜有研究对土地城镇化与人口城镇化之间的互动关系进行实证检验。本研究利用我国2005—2013年间的省级面板数据考察各省级行政区土地城镇化与人口城镇化的非协调性,并通过构建和估计面板向量自回归模型探究土地城镇化与人口城镇化之间的互动关系。研究发现,土地城镇化与人口城镇化的非协调性存在着显著的时空差异。在样本期的后半段(2009—2013年),多个省级行政区人口城镇化滞后于土地城镇化的程度有所加深。根据全样本期内土地城镇化与人口城镇化非协调性的严重程度,可将各省级行政区划分为5个等级。城镇常住人口变化对建成区面积变化具有显著的正向影响;建成区面积变化对城镇常住人口变化的影响方向虽然为正,但该影响不具有统计显著性。从而表明人口城镇化对土地城镇化起到了推动作用,但土地城镇化却未能有效地带动和促进人口城镇化。此外,第二、三产业增加值变化对城镇常住人口变化具有显著的正向影响。研究从改革新增建设用地指标分配方式、抑制城市空间粗放扩张及推动户籍制度改革和基本公共服务均等化等方面提出了促进土地城镇化和人口城镇化协调发展的政策建议。  相似文献   
35.
面对水体富营养化愈来愈严重,水华爆发越来越频繁的严峻形式;为减少水华发生频率及由此造成的损失,开展水华预警已成当务之急。水华爆发是水体中营养盐的累积、气候条件与水力条件等众多因素非线性共同作用的产物;为此,有必要在众多水华影响因素的动态监测信息的融合基础上,寻求水华爆发与这些影响因素间的影射关系,这就需要信息融合技术。通过归纳总结多源信息融合技术在内陆湖库水华预警中应用的研究进展,结合目前我国水华预警的具体需求,提出建立基于多源信息融合技术的水华预警决策支持系统的研究前景与初步设想。信息融合技术为水华预警提供了一个良好的平台,它将与水华相关的不同信息源(水文、气象、水环境质量与环境遥感)所提供的局部不完整的观测信息加以集成与互补,消除多源信息之间存在的冗余和矛盾,形成对水华爆发环境相对完整的感知与描述;从而提高水华预警与应急响应决策的效率,提高预警信息的时间与空间分辨率,扩展信息的时空监测范围。  相似文献   
36.
Environmental disputes arise due to opposing views of various groups about their environmental concerns and their economic or developmental interests. Development and protection of the environment constitute two main contradictory objectives within the sustainable development paradigm, which are often in conflict. The decision support system, GMCR II, which implements the graph model for conflict resolution, is employed to model and analyze an environmental dispute arising over the construction of a new freeway between the Iranian capital, Tehran, and the city of Chalous located in the north of the country. This study demonstrates that the graph model for conflict resolution can be used as a methodology to promote a reasonable balance between economic development and environmental protection from a strategic viewpoint. In addition to systematically modelling the conflict by putting the existing information into proper perspective, it is shown how conflict analysis can be used for comparing alternative scenarios and predicting possible future outcomes. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   
37.
In many European countries, accommodating water has become the dominant paradigm in river management. In the Netherlands, extensive river restoration projects are being implemented, many of which draw serious opposition from the public. To investigate the causes of such opposition, a comprehensive study of public attitudes towards river restoration was conducted in three floodplains, both before and after river restoration. The study combined quantitative questionnaires (N = 562) with open interviews (N = 29). This paper describes how local residents perceive the effects of river restoration on landscape quality and how residents and protest groups use landscape quality in combination with other arguments to strategically frame river management policies. Results show that measurement of the perceived outcomes of nature restoration needs to be complemented by a more dynamic type of research, focusing on the social processes of the framing of restoration plans. Theoretically, the paper aims to contribute to the development of a rigorous research strategy to study framing processes in environmental management, using a mixed-methods approach.  相似文献   
38.
This study investigated user wayfinding navigational performance in terms of two navigational support designs (guide sign and you-are-here map, i.e., YAH), wayfinding strategies (egocentric/route and allocentric/survey), task difficulty (terrestrial/2D or weightless/3D), and gender differences. Eighty participants (40 males and 40 females) were recruited for the wayfinding experiment. The experimental results and statistical analysis indicated that, in the weightless VR scene, navigation time for the terrestrial/2D task type was significantly shorter than for the weightless/3D task type. The guide sign support was significantly more effective than YAH map support. Moreover, the interactions between support style and gender difference indicated that males exhibit better wayfinding performance than females, but that appropriate support can improve navigational performance and eliminate gender differences. In addition, the Way-Finding Strategy Scale result showed that the females were more likely to adopt the egocentric strategy while males were more likely to adopt the allocentric strategy, and that their scores were negatively correlated with navigational performance. Our results can be used to evaluate the interface designs of navigational support systems taking into consideration gender differences with respect to 3D VR games, including VR diving or flying navigational systems.  相似文献   
39.
Decision–support systems in the field of integrated water management could benefit considerably from social science knowledge, as many environmental changes are human-induced. Unfortunately the adequate incorporation of qualitative social science concepts in a quantitative modeling framework is not straightforward. The applicability of fuzzy set theory and fuzzy cognitive maps for the integration of qualitative scenarios in a decision–support system was examined for the urbanization of the coastal city of Ujung Pandang, Indonesia. The results indicate that both techniques are useful tools for the design of integrated models based on a combination of concepts from the natural and social sciences. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
40.
Because of fast urban sprawl, land use competition, and the gap in available funds and needed funds, municipal decision makers and planners are looking for more cost-effective and sustainable ways to improve their sewer infrastructure systems. The dominant approaches have turned to planning the sanitary sewer systems within a regional context, while the decentralized and on-site/cluster wastewater systems have not overcome the application barriers. But regionalization policy confers uncertainties and risks upon cities while planning for future events. Following the philosophy of smart growth, this paper presents several optimal expansion schemes for a fast-growing city in the US/Mexico borderlands—the city of Pharr in Texas under uncertainty. The waste stream generated in Pharr is divided into three distinct sewer sheds within the city limit, including south region, central region, and north region. The options available include routing the wastewater to a neighboring municipality (i.e., McAllen) for treatment and reuse, expanding the existing wastewater treatment plant (WWTP) in the south sewer shed, and constructing a new WWTP in the north sewer shed. Traditional deterministic least-cost optimization applied in the first stage can provide a cost-effective and technology-based decision without respect to associated uncertainties system wide. As the model is primarily driven by the fees charged for wastewater transfer, sensitivity analysis was emphasized by the inclusion of varying flat-rate fees for adjustable transfer schemes before contracting process that may support the assessment of fiscal benefits to all parties involved. Yet uncertainties might arise from wastewater generation, wastewater reuse, and cost increase in constructing and operating the new wastewater treatment plant simultaneously. When dealing with multiple sources of uncertainty, the grey mixed integer programming (GIP) model, formulated in the second stage, can further allow all sources of uncertainties to propagate throughout the optimization context, simultaneously leading to determine a wealth of optimal decisions within a reasonable range. Both models ran for three 5-year periods beginning in 2005 and ending in 2020. The dynamic outputs of this analysis reflect the systematic concerns about integrative uncertainties within this decision analysis, which enable decision makers and stakeholders to make all-inclusive decisions for sanitary sewer system expansion in an economically growing region.  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