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   124篇
  免费   4篇
  国内免费   20篇
安全科学   5篇
废物处理   2篇
环保管理   26篇
综合类   48篇
基础理论   9篇
污染及防治   6篇
评价与监测   7篇
社会与环境   11篇
灾害及防治   34篇
  2023年   3篇
  2022年   2篇
  2021年   1篇
  2020年   3篇
  2019年   2篇
  2018年   2篇
  2017年   4篇
  2016年   4篇
  2015年   3篇
  2014年   2篇
  2013年   8篇
  2012年   3篇
  2011年   13篇
  2010年   6篇
  2009年   6篇
  2008年   6篇
  2007年   6篇
  2006年   5篇
  2005年   9篇
  2004年   7篇
  2003年   4篇
  2002年   3篇
  2001年   2篇
  2000年   7篇
  1999年   1篇
  1998年   5篇
  1997年   3篇
  1996年   3篇
  1995年   4篇
  1994年   8篇
  1992年   3篇
  1991年   1篇
  1990年   3篇
  1988年   2篇
  1987年   1篇
  1982年   1篇
  1977年   1篇
  1976年   1篇
排序方式: 共有148条查询结果,搜索用时 31 毫秒
101.
ABSTRACT: An allocation model for irrigation water cost, based on the Use of Facilities method, is presented. The model is developed for large-scale irrigation systems which may include multipurpose reservoirs, irrigation control works, pump stations and irrigation canals of various orders. The model accounts for the water conveyance losses as well as the water gains in the irrigation canals, and their effects on irrigation cost. It is applied to the irrigation distribution system of the Nile Valley in Egypt, which contains the High Aswan Dam, 16 irrigation structures, 12 pump stations, and numerous irrigation canals. The irrigation water cost at 29 areas representing the Nile Valley is determined.  相似文献   
102.
ABSTRACT: Estimations of runoff volumes from urban areas can be made by the equation Q = a A σ(Pe– b), where Q is the runoff volume, a is the part of the total area A Contributing to runoff, Pe is the rainfall amount for a single event, and b is the initial rainfall losses. For the evaluation of a and b, rainfall/runoff measurements were made in five areas of sizes between 0.035 km2 and 1.450 km2. By linear regression analysis of rainfall volumes versus runoff volumes, the initial rainfall losses were found to vary from 0.38 mm to 0.70 mm for the different areas. The parts of the areas contributing to runoff were found to be proportional to the impermeable parts of the mas. The equation is applicable in urban areas with well defined paved surfaces and roofs and with a negligible amount of runoff from permeable areas.  相似文献   
103.
打通“绿水青山就是金山银山”转化路径是生态经济研究的重要内容,也是衔接脱贫攻坚和乡村振兴的有效途径.结合扶贫领域生态环境保护项目实施情况,从生态保护修复效益、环境污染治理效益、“绿水青山就是金山银山”转化效益方面构建了生态环境损益与“绿水青山就是金山银山”转化效益评估指标体系,并选择江西省崇义县进行案例研究.结果表明:①构建的生态环境损益与“绿水青山就是金山银山”转化效益评估指标体系包括生态保护修复实现的增值量、环境污染治理产生的减损量和“绿水青山就是金山银山”转化的经济收入.②崇义县良好生态环境实现的“绿水青山就是金山银山”转化效益初步显现,2018年崇义县“绿水青山就是金山银山”转化的经济收入为22.77×108元,是2013年的3.77倍,通过“绿水青山”向“金山银山”转化的经济收入得到逐步释放.③生态环保扶贫不仅可以提高区域生态环境质量,而且可以防止产生新的生态破坏与环境污染事件,通过发展生态经济,促进贫困地区县域经济绿色转型发展,巩固脱贫攻坚成果和支撑乡村振兴.研究显示,着眼于生态环保扶贫促绿色转型发展和生态产品价值实现,保护修复生态环境获得合理回报,“绿水青山就是金山银山”转化效益评估包括绿色有机农产品产值、生态旅游和生态补偿类收入,指标简单、可操作性强,可为生态环保扶贫政策优化和贫困地区可持续发展管理提供参考.   相似文献   
104.
ABSTRACT: A reach of the Pecos River, located in eastern New Mexico, was examined to evaluate losses of river flows due to evaporation, seepage, and transpiration. An accurate assessment of the water losses along this reach is critical for determining how water rights are adjudicated for water users in the Pecos basin and interstate compact accounting. Water losses significantly impact flows through critical habitat for species protected under the Endangered Species Act. Daily losses of river flows were analyzed for the study reach that extends from immediately below the Pecos River confluence with Taiban Creek to the United States Geological Survey (USGS) gage near Acme. The analysis was completed with consideration for other processes including flood wave travel times and attenuation along with stream bank storage and returns. The analysis was completed using daily stream flow data from USGS gages located along the study reach. Empirical seasonal functions were developed to relate flow loss to the flow rate in the river. The functions were ultimately developed to provide a method for comparing the effects of different river flows on the available water supply.  相似文献   
105.
We analyzed the past and current distribution and abundance of vegetation and wildlife to develop a wildlife habitat restoration plan for the Sweetwater Regional Park, San Diego County, California. Overall, there has been a substantial loss of native amphibians and reptiles, including four amphibians, three lizards, and 11 snake species. The small-mammal community was depauperate and dominated by the exotic house mouse (Mus musculus) and the native western harvest mouse (Reithrodontomys megalotis). It appeared that either house mice are exerting a negative influence on most native species or that they are responding positively to habitat degradation. There has apparently been a net loss of 13 mammal species, including nine insectivores and rodents, a rabbit, and three large mammals. Willow (Salix) cover and density and cottonwoods (Populus fremontii) had the highest number of positive correlations with bird abundance. There has been an overall net loss of 12 breeding bird species; this includes an absolute loss of 18 species and a gain of six species. A restoration plan is described that provides for creation and maintenance of willow riparian, riparian woodland, and coastal sage scrub vegetation types; guides for separation of human activities and wildlife habitats; and management of feral and exotic species of plants and animals.  相似文献   
106.
溢油事故造成的海湾生态系统服务损失的货币化评估   总被引:2,自引:0,他引:2  
海湾是人类活动的密集地带,它以其特有的生态系统为人类的生产和生活提供了物质和精神方面的多种服务。从海湾生态系统服务的分类入手,在分析溢油事故可能给海湾生态系统的供给、调节、文化和支持服务带来的各种负面影响的基础上,运用市场价值法、替代市场法、调查评价法和成果参照法,构建了海湾生态系统服务(子服务)损失货币化评估的相应计量模型。  相似文献   
107.
地震灾害导致企业资产遭受损失,为了科学合理的制定灾区企业恢复生产和重建工作的计划,需要对企业灾害损失进行快速的评估.本文从统计的角度提出了一种估算灾区企业固定资产损失情况的方法,并以汶川地震为例对此方法进行效验.  相似文献   
108.
China’s counterpart assistance policy is of vital importance in providing guidance for emergency management and post-disaster reconstruction. However, the amount of assistance that partner provinces should provide as well as the criteria that partners should abide by in offering counterpart assistance remain a main challenge. The goal of this research is to fill this gap by proposing a new framework consisting of an interregional input–output (IRIO) model and a resilience index. Subsequently, the indirect economic loss is obtained by utilizing the index system of provincial economic resilience assessments, with measures of indirect economic loss developed from the IRIO. Furthermore, to examine the internal validity and systematic error, the reliability of the adopted models, the calculation methods, and the index systems are investigated. To assess the external validity of the proposed measures and resilience index of the framework, data from the 2008 Wenchuan Earthquake are applied for estimating parameter values of the framework, and a follow-up investigation was conducted for examining the fairness and enhanced effectiveness of the new counterpart assistance criteria. In summary, this paper attempts to present some new ideas about the analysis of economic motivations of mutual aid and the improvement of the counterpart assistance policy.  相似文献   
109.
介绍了一种基于嵌入式PDA设备的专业系统"火灾直接财产损失评估移动终端系统"的软件结构设计过程。该软件以公安部发布的公共安全行业标准《火灾直接财产损失统计方法》GA185—1998为计算依据,解决了嵌入式PDA设备的软件开发和编制问题,可用于房屋建筑、设备及其他财产和文物建筑的火灾损失计算和统计,并可生成数据文件,用于与之相匹配的"火灾直接财产损失评估PC系统"中进行统计和汇总,可随时随地地在火灾现场方便地进行直接财产损失计算和统计,能给消防工作人员带来很大便利。  相似文献   
110.
江苏太湖地区水污染损失估算   总被引:7,自引:0,他引:7  
葛吉琦 《环境科学》1992,13(2):68-72,32
本文对江苏太湖地区水污染造成的经济损失,用生产率、恢复费用、防护费用、机会成本、人力资本的方法进行了估算。结果表明,在1985—1988年期间,损失年均10.08亿元,约占国民生产总值的3.12%。  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