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   106篇
  免费   3篇
  国内免费   3篇
安全科学   1篇
废物处理   2篇
环保管理   32篇
综合类   27篇
基础理论   28篇
污染及防治   6篇
评价与监测   7篇
社会与环境   8篇
灾害及防治   1篇
  2023年   1篇
  2022年   2篇
  2021年   3篇
  2020年   4篇
  2019年   2篇
  2018年   1篇
  2017年   3篇
  2016年   1篇
  2015年   5篇
  2013年   2篇
  2012年   5篇
  2011年   6篇
  2010年   7篇
  2009年   6篇
  2008年   7篇
  2007年   9篇
  2006年   4篇
  2005年   8篇
  2004年   8篇
  2003年   5篇
  2002年   2篇
  2001年   3篇
  2000年   7篇
  1999年   3篇
  1998年   1篇
  1997年   1篇
  1994年   3篇
  1991年   1篇
  1987年   1篇
  1984年   1篇
排序方式: 共有112条查询结果,搜索用时 15 毫秒
61.
等温超塑挤压成形技术开辟了铜合金实体保持架加工的新途径。在此新技术的基础上,利用VC++6.0和ObjectARX开发了一套铜合金轴承实体保持架挤压模CAD系统软件,大幅度缩短了保持器系列产品的开发周期,并提高了产品设计效率和设计水平。  相似文献   
62.
The study analyses the contribution of relevant economic actors to the provision of private and public goods in agricultural landscapes. A method consisting of a multi-sectoral perspective and an integrated approach based on the analytic network process (ANP) and the use of selected local stakeholders is applied. The usefulness of the method is demonstrated in three European case studies in Austria, Italy and Spain. The results show that agriculture and tourism are the sectors that contribute the most and the least, respectively, to the provision of goods and services in agricultural landscapes. Moreover, the results underscore that policy instruments towards such provision need to be targeted differently in different areas and must take into account the different roles of the local actors involved.  相似文献   
63.
Amenity migration to attractive and accessible non-metropolitan areas changes social and environmental relations with consequences for natural resource management and landscape composition and trajectories. Lifestyler oriented rural landholders are often cast as a problem for land management and extension. Managers and some researchers see them as a cause of landscape and social fragmentation and report difficulties in engaging such landowners on natural resource management issues and responsibilities. In contrast, limited existing research indicates that lifestylers do join and form networks of personal and other contacts for advice and support in land management. We contribute to this research with a survey of rural landholders in southeastern New South Wales (NSW). We explicitly compare the sources of advice for land management for lifestylers with those of farmers. We focus on the types of sources available to rural landholders in Australian regions and their relative importance to these two landholder groups. We find that lifestylers and farmers are different in their sources of advice but that both prefer personal sources rather than sources such as agencies. We reflect on the significance of the differences for engagement with lifestyle oriented rural landowners and for understanding landscape change.  相似文献   
64.
江西三清山花岗岩峰林地质公园特征及评价   总被引:6,自引:1,他引:6  
三清山位处扬子板块与华夏板块结合带,区内花岗岩受北东、北西和北东东向三条断裂控制,形成典型的三角形断块山,地貌处于幼年晚期至壮年早期发育阶段.园区内花岗岩峰峦、峰丛、峰墙、峰柱、石芽及造型石等微地貌景观发育,类型齐全,分布集中,集结了花岗岩峰林地貌的精华,为世界罕见;兼具千年道教文化和秀美自然风光,具有极高的科研、科普和旅游观赏价值.  相似文献   
65.
阐述了小模数渐开线花键的滚轧成形 ,滚轮的设计及制造。制造工艺采用线切割成形 ,工艺简单。  相似文献   
66.
环境决策支持系统的设计技术及发展趋势   总被引:2,自引:2,他引:2  
简要论述了环境决策支持系统(EDSS)的发展历程,提出了EDSS开发技术的六大构成部分:应用平台的选择;系统的开发方式的选择;系统的开发工具的选择;系统的组成结构的建立;系统的基本功能的设计;系统的开放接口的设计。对系统设计的关键技术进行了分析,依据EDSS的应用现状,指出EDSS的发展趋势,对实际应用具有一定的指导意义和实用价值。  相似文献   
67.
Around 1970 a quiet revolution occurred in several European countries involving the use of naturalistic design approaches and ecological principles in the design and management of urban green spaces. The objective was to bring the qualities of nature into peoples’ daily lives and provide a richer external living environment. Parallel programmes of community participation and environmental education were involved. Successful projects in Holland, Sweden and Britain are described. These indicate that despoiled urban and urban‐fringe land can be quickly and economically transformed into green environments which are attractive for living and commercial investment. A reorganisation of Local Authority landscape resources is recommended.  相似文献   
68.
The repurposing of military lands is common in many parts of the world and presents a variety of conservation opportunities. This study examines land cover at Big Oaks National Wildlife Refuge, Indiana (U.S.A.) as it transitioned from military proving ground to wildlife refuge from 1985 to 2013. We use remote sensing, semi-structured interviews, and a review of planning and management documents to examine this transition. Limited change in land cover composition and distribution are detected, despite changes in use and management. This landscape similarity relates to similarities in land management practices, and the impact of landscape history on current management practices. The findings suggest that military use and conservation objectives at this site yield similar land covers and are not necessarily in contrast to each other. As military base closures continue, the potential to maintain and expand conservation opportunities on these lands will likely grow in importance.  相似文献   
69.
This paper describes an integrative method for quantifying, analyzing, and comparing the effects of alternative rehabilitation approaches with visual preference. The method was applied to a portion of a major industrial area located in southern Italy. Four alternative approaches to rehabilitation (alternative designs) were developed and analyzed. The scenarios consisted of the cleanup of the brownfields plus: (1) the addition of ground cover species; (2) the addition of ground cover species and a few trees randomly distributed; (3) the addition of ground cover species and a few trees in small groups; and (4) the addition of ground cover species and several trees in large groups. The approaches were analyzed and compared to the baseline condition through the use of cost-surface modeling (CSM) and visual preference assessment (VPA). Statistical results showed that alternatives that were more ecologically functional for forest bird species dispersal were also more visually preferable. Some differences were identified based on user groups and location of residence. The results of the study are used to identify implications for enhancing both ecological attributes and visual preferences of rehabilitating landscapes through planning and design.  相似文献   
70.
国内外空气质量监测网络设计方法研究进展   总被引:2,自引:3,他引:2  
如何设计效率高、代表性好、目的性强的空气质量监测网络,是长期以来空气质量监测工作的难点与关键。随着环境管理水平的提高,环境空气质量监测网络的设计成为当前研究的热点之一,国内外很多学者对其进行了广泛的研究。文章对美国、欧盟和我国关于空气质量监测网络设计的规范进行了简要评述和比较分析,并参考国内外一些关于空气质量监测网络设计的研究和应用实例,对当前主要的设计方法及应用进展进行了综述。  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