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   874篇
  免费   20篇
  国内免费   65篇
安全科学   15篇
废物处理   6篇
环保管理   291篇
综合类   248篇
基础理论   168篇
污染及防治   26篇
评价与监测   26篇
社会与环境   144篇
灾害及防治   35篇
  2024年   2篇
  2023年   12篇
  2022年   10篇
  2021年   10篇
  2020年   10篇
  2019年   16篇
  2018年   17篇
  2017年   18篇
  2016年   26篇
  2015年   25篇
  2014年   28篇
  2013年   68篇
  2012年   31篇
  2011年   46篇
  2010年   36篇
  2009年   31篇
  2008年   22篇
  2007年   47篇
  2006年   39篇
  2005年   40篇
  2004年   41篇
  2003年   47篇
  2002年   32篇
  2001年   45篇
  2000年   42篇
  1999年   40篇
  1998年   22篇
  1997年   30篇
  1996年   28篇
  1995年   21篇
  1994年   12篇
  1993年   15篇
  1992年   11篇
  1991年   9篇
  1990年   5篇
  1989年   2篇
  1988年   6篇
  1987年   1篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1980年   4篇
  1979年   1篇
  1978年   2篇
  1976年   1篇
  1974年   1篇
  1972年   1篇
  1971年   1篇
排序方式: 共有959条查询结果,搜索用时 484 毫秒
581.
森林资源可持续利用与山区综合开发是21世纪林业关注的热点。本文通过介绍虞山宝岩高科技农林生态观光园的规划,旨在探讨新形式下农林综合开发的新思路  相似文献   
582.
20世纪80年代以来洪湖流域营养物质输移模拟研究   总被引:1,自引:0,他引:1  
桂峰  于革 《长江流域资源与环境》2007,16(A02):127-132,157
选择位于长江中游的洪湖流域作为研究对象,应用流域分布式水文模型SWAT,探讨现代农业条件下流域面源营养盐输移的规律。模拟时段选择为1983~2002年。模拟的边界条件设置为自然地形、土壤、现代农业生产及土地利用方式,其中土壤资料包括营养盐(N和P)、有机质含量、粒径等理化参数。径流量与营养盐输出模拟结果与实测值有较好的吻合程度,可以通过置信度95%的显著性检验。模拟结果显示,现代农业条件下流域营养盐输出,TN和TP浓度变化有明显的季节特征,体现了区域耕作方式、径流对营养盐输出浓度的影响。模拟时段内营养盐输出浓度呈明显增长趋势,体现了农药化肥的施用对流域营养盐输移的影响。  相似文献   
583.
Abstract

The Three Gorges Project attracts worldwide attention because of the Three Gorges migrants, and the agriculture of the Three Gorges Reservoir Area is a foundation for the development of the Three Gorges migrants. The Three Gorges Reservoir Area is situated at the mountainous area with bad agricultural development conditions and relatively low levels of development. As a result, the large-scale migration has special influence on its agricultural development, which has attracted much attention. The paper analyzes influence that the migrants have forced on its agricultural development based on the scientific data, and makes some explorations on the models that are suitable for the development of mountainous agriculture in the Three Gorges Reservoir Area  相似文献   
584.
Focusing on recent documentaries about sustainable agriculture in the US—Food, Inc., The Garden, Fresh, and Farmageddon—this paper examines how pro-sustainable food arguments fail to merge environmentalism and environmental justice. By framing their approach to sustainable food production around the normative issue of “good food” for capitalist consumers, such documentaries ignore questions about community and cultural conceptions of farmers. In the process the films promote a problematic vision of the white family farm. As a consequence, these films limit a reimagining of alternative food systems, the roles for diverse actors within those systems, and possibilities for eaters beyond “voting with your fork.” Several exceptions, most notably The Garden, are used to suggest how cinema might radically re-envision participation in alternative forms of agriculture.  相似文献   
585.
A variety of tools can be employed in support of environmental policy objectives, but achieving preferred outcomes also requires the cooperation of private landholders and others with vested interests in the land. The Land Stewardship project in the state of Victoria, Australia, is an initiative devoted to exploring the ways in which private landholders could be encouraged towards more sustainable land management. Following the view that the success of policy initiatives is contingent on effective stakeholder engagement, a component of the Land Stewardship project involved a dialogue with landholders about policy tools (e.g., regulation, economic instruments) that might be deployed to encourage improved land management practices. This paper provides an account of the views and attitudes of landholders, as revealed in a series of three workshops, which consisted of discussions about the factors influencing agriculture, participants' interpretations of sustainability, and policy methods. The focus of the paper is on what landholders believe to be the strengths and limitations of standard policy tools, and the essential requirements for these tools to deliver the best land management outcomes. One of the main findings of the project was a 'preference hierarchy' in respect of policy methods, according to which the strongest support was expressed for voluntary and education-based tools, followed by market-based instruments, with command-and-control regulation identified as a measure of 'last resort'. In the paper we reflect also on how the views and outlook of landholders should be positioned relative to other inputs in the design of policy interventions.  相似文献   
586.
国内城市构建"休闲之都"的资质条件分析   总被引:3,自引:0,他引:3  
分析了国内部分城市构建休闲都市的资质条件.休闲是时代发展的必然趋势,构建“休闲之都”是当今社会发展的需要,国内不少优秀的旅游城市正在探索营造休闲都市。在给出对休闲都市的概念、特征后,遴选国内20个城市运用离差最大化法进行构建休闲都市的资质分析,以期得出一个较为客观的结论。  相似文献   
587.
欧盟于2020年10月出台了《欧盟甲烷减排战略》,以支撑其中长期温室气体减排目标。该战略共提出了五个领域的24个行动方案。欧盟将油气行业作为重点,设置了两个强制性的政策来完善能源部门的温室气体监测、报告和核查制度,并禁止天然气放空和燃烧。农业领域以加强全生命周期甲烷排放核算、减排技术等方面研究,编制最佳减排实践和技术清单为主要措施。在废弃物管理领域,欧盟将主要修订废弃物管理方面的立法和废水处理标准并加强监管。全球层面,欧盟提出希望联合包括中国在内的主要油气进口国家,推动建立全球性的监测、报告和核查标准,分享其甲烷超级排放源探测的卫星数据等措施。我国提出2060碳中和愿景后,下一阶段温室气体减排将会从能源相关二氧化碳减排为主扩展到全部温室气体减排。建议我国和欧盟在甲烷减排方面开展广泛合作,借鉴欧盟的经验,尽快制定我国甲烷减排近期、中期、远期目标和行动计划,推广甲烷减排技术,加强科学研究和技术研发,探索在国家碳市场交易体系中纳入甲烷等非二氧化碳气体的时机和方案,鼓励大型能源企业加入国际甲烷减排倡议以提高能力,逐步完善我国甲烷减排相关政策和制度环境,打造我国在低碳领域的经济和技术竞争力。  相似文献   
588.
This Impacts article proposes strategies for mitigating negative impacts of urbanization in rural locations in the United States. Issues addressed include impacts of population growth and development, loss of agricultural lands, and impacts of climate change on agriculture and rural communities. Conclusions are supported by stakeholder survey data, geographic information systems-based data, and desktop reviews of research journal publications. We propose a sustainable, diversified approach that supports mitigation of issues, including increasing demand on food production and decline of rural communities. A key issue that we address is where we will find suitable landscapes to reduce enough food for 9.6 billion people living in 2050.

Urban and rural development planners are grappling with solutions to escalating impacts global populations, stresses on food production, and effects of climate change. Solutions are identified, including strengthening rural and urban contexts by establishing connected and interdependent links that support diversification of rural and urban contexts as viable solutions to these issues.

Diversified rural-to-urban sustainable agriculture production is a promising approach to addressing climate change impacts. Organic agriculture principles exhibit strong diversity and are accredited by United States Department of Agriculture as the only federally certified sustainable agriculture practice in the United States. Sustainable agriculture practices are evolving into profitable diversified alternative food sources. We offer substantiated alternative solutions for remediating impacts of urbanization on rural agriculture and communities. Collectively, these solutions can strengthen symbiotic relationships between sustainable agriculture and rural communities, addressing our growing population issues and preserving our dwindling farmlands and rural communities.  相似文献   

589.
ABSTRACT. A mathematical model to predict water quality in a surface-groundwater system is under development. This project is being sponsored by the Environmental Protection Agency. The ultimate goal of this study is to obtain cause and effect relationships between pollutant sources and the ensuing concentrations at different locations in a basin. Several programs are used to model the various hydrologic processes occurring in nature, namely: rainfall, runoff, flow in surface bodies of water, infiltration, and groundwater flow. At every time step in the simulation, the water quantity computations for the above hydrologic models are performed first. Subsequently, the results of these computations, typically in the form of flow velocities, are used as input to the water quality calculations. The water quality routines involve the modeling of the associated physical, chemical, and biological processes. In this study, emphasis is being placed on pollution in agricultural areas. Accordingly the Lake Apopka basin in Central Florida is being used as the application site.  相似文献   
590.
利用信息技术建立农村信息服务体系   总被引:6,自引:0,他引:6  
以学校信息公共服务体系为依托,以网络、通讯、电视等信息技术为基础,建立雅安星火科技网、农民科技110、电视网络”三套信息服务系统,同时用三套信息服务系统向农民传输信息。这对指导农业生产的产前、产中和产后管理,农业结构调整,改造传统农业,推动农业信息化和智能化的发展,实现农业和国民经济可持续发展,具有十分重要的作用和意义。  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