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   5018篇
  免费   191篇
  国内免费   379篇
安全科学   362篇
废物处理   157篇
环保管理   1079篇
综合类   2009篇
基础理论   597篇
环境理论   6篇
污染及防治   211篇
评价与监测   63篇
社会与环境   1028篇
灾害及防治   76篇
  2024年   6篇
  2023年   37篇
  2022年   53篇
  2021年   80篇
  2020年   83篇
  2019年   81篇
  2018年   99篇
  2017年   117篇
  2016年   114篇
  2015年   104篇
  2014年   152篇
  2013年   395篇
  2012年   226篇
  2011年   305篇
  2010年   221篇
  2009年   246篇
  2008年   179篇
  2007年   357篇
  2006年   348篇
  2005年   291篇
  2004年   298篇
  2003年   300篇
  2002年   294篇
  2001年   241篇
  2000年   243篇
  1999年   197篇
  1998年   127篇
  1997年   113篇
  1996年   66篇
  1995年   68篇
  1994年   47篇
  1993年   30篇
  1992年   12篇
  1991年   12篇
  1990年   6篇
  1989年   5篇
  1988年   5篇
  1987年   5篇
  1986年   3篇
  1984年   4篇
  1983年   2篇
  1981年   4篇
  1980年   2篇
  1978年   3篇
  1977年   4篇
  1975年   1篇
  1972年   1篇
  1971年   1篇
排序方式: 共有5588条查询结果,搜索用时 375 毫秒
931.
Sustainability demands that managers deliberate effects on stakeholders and the environment alongside traditional profitability measures. This paper presents a case study suggested by the managers of a distribution firm that seeks to balance environmental impact with cost in an industrial distribution network configuration decision incorporating product returns, which is currently taking place. While this can be modelled using mathematical programming, nonlinear terms in the objective functions as well as the likeliness that a large number of combinations of binary decision variables result suggest that this will not be able to be relied upon for a solution. For this reason, we propose a heuristic that aims at finding the Pareto-efficient frontier, which managers can use to deliberate the best solution balancing cost and environmental impact, according to the relative trade-offs of various possible configurations. We illustrate this heuristic on the Italian region of Liguria, and further explore trade-offs juxtaposing the regions of Lombardi and Sicily. Lastly, various extensions for enhanced product recovery opportunities for returns are suggested.  相似文献   
932.
Sustainability has become a very significant research topic as it impacts many different manufacturing industries. Therefore, the technologies for monitoring, analysing, evaluating and optimising the sustainability performance of manufacturing processes and systems are very critical for decision makers on the shop floor. This paper introduces a decision guidance management system that provides actionable recommendations through quantitative analysis of the sustainability measures of manufacturing processes and systems based on life cycle assessment. The system determines decision preferences through dynamically collected data and decision makers' responses, taking into account the prevailing constraints. Optimal decisions can be derived using mathematical and constraint programming. By using decision guidance query language, this methodology allows users to make optimal decisions without an extensive mathematical or operations research background. Knowledge of relational databases is sufficient for a user to formulate the optimisation problem and obtain optimal solutions. The methodology is demonstrated with a machining operation case study, in which a list of sustainability metrics are identified and sustainability modelling methods are proposed. Important sustainable machining performance measures are optimised, resulting in actionable recommendations.  相似文献   
933.
中国西部城镇化可持续发展路径的探讨   总被引:3,自引:0,他引:3  
基于对中国西部地区城镇化进程的调研,本文探讨了西部地区城镇化可持续发展的路径,结合西部地区的现状与西部地区城镇发展的历史趋势,分析了中国西部地区城镇化发展的需求,阐析了其城镇化进程中的环境压力与阻力,提出了促进中国西部城镇化可持续发展的政策建议.目前,西部地区整体城镇化水平滞后,各省(区)间的城镇化发展水平极不均衡.而社会经济发展水平对于城镇化具有很大的促进作用,故未来相当一段时间内,西部地区社会经济发展是其区域城镇化进程的主要动力,同时西部地区尚处于城镇化与工业化发展的正相关期,工业化水平的提升对西部地区城镇化进程的推动作用不容小觑.城镇化进程的不断加快和工业化的快速推进过程中,西部地区本就脆弱的生态环境存在进一步遭受损失与破坏的威胁.这些将会导致西部地区生态环境状况的恶化转而成为其城市化的严重制约,给当地经济可持续发展造成一定程度的影响.据此,文中提出建议,未来西部城镇化建设过程中,应推行“二元”城镇化发展战略,增强中心城镇的辐射带动作用,培育中小城市和特色鲜明的小城镇;进一步完善西部城镇基础设施水平,以各级政府支持管理为先导和主导,尝试采用“公私营合作”(PPP)融资模式,重点推进交通及通讯设施建设;构建长期稳定的绿色城镇发展战略,推进城市绿色文化、建设绿色城市,筹措西部地区绿色城镇发展基金、发展城市绿色产业;立足功能分区并结合城镇化战略格局优化城镇化发展,依托国家主体功能区划优化城镇化发展格局,结合“两横三纵”城镇化战略格局推进城市群建设.  相似文献   
934.
This paper is the first recorded economic value of living fossil,an evaluation of the basic economic value of Lingula,based on the direct utilization of households for food and sale.Twenty-one local fishermen who collected Lingula in Trat Province were focused on by using interview questionnaires.The animal habitats are influenced by the encroachers’age,gender and harvest method.The total economic value in 2011 was around two million baht.Those who possess fishing gear and have more money can have greater access to the product The local communities in Nong Khunsong sub-district are successful in collecting the Lingula and in doing local business.The market channel analysis is conducted at local,provincial and national levels and short market chains are demonstrated in the form of a wholesale market in the Lingula trade.This represents significant consumption by the local communities.The study further recommends sustainable conservation and management efforts at a local scale.  相似文献   
935.
Abstract

Nowa days, ecological and cultural tourism, especially those ancient villages and towns in China, have attracted an increasing number of tourists because of their unique cultural features. However, rapid development of tourism brings economic benefits, but results in a series of problems that threaten further tourism development and protection of ancient towns, such as over-commercialization and tourism urbanization. Taking Longmen ancient town as an example, this paper presented a sustainable way of preserving and developing resources of ancient villages and towns. First, identify cultural features and the extent of ancient villages and towns, and find the approach through which a cultural landscape zoning can be applied. Second, define a cooperative function area to release the pressure on core areas and protect their authentic cultures by extending tourism space. Third, balance tourism development with traditional industries to enhance the sustainability of community economies.  相似文献   
936.
可持续发展与中国生态文明理念的提出和演化是一个不断深入、循序渐进的历史过程,与全球形势和中国具体国情发展变化密不可分,两者存在紧密联系。主要体现在:中国生态文明建设与全球可持续发展历程遥相呼应,生态文明理念是可持续发展理论的延伸拓展与中国化,两者的实现途径是一致的;二者都是在资源环境约束和经济社会发展矛盾日益突出的背景下提出的,都强调不同领域的协调和融合,强调环境保护的重要性,但又同样不等同于环境保护。  相似文献   
937.
为厘清应急管理学科建设机制、推进应急管理学科良性发展,通过回顾学科建设历史,来分析应急管理学科建设面临的困境与肩负的使命,并提出相应的建设路径.研究表明:在知识生产模式转型视角下,应急管理学科建设面临知识生产者离散、知识创新度不足、知识转化率有限的三重困境,需要完成"朝向人才培养的应急管理知识直接再生产""朝向科学研究...  相似文献   
938.
唐舒庭  卢一铭  肖盛柏  崔浩  魏世强 《环境科学》2023,44(10):5704-5717
砷(As)和镉(Cd)是稻田土壤中最常见的有毒有害重金属元素,且易从土壤迁移到水稻籽粒中.目前,我国稻田土壤中As和Cd及其复合污染现象普遍,对粮食安全和人体健康均构成了严重威胁.As和Cd在土壤中的环境行为相反,对As-Cd复合污染的同步治理是当前水稻安全生产的关键技术难点.通过综述近年来同步阻控水稻对As和Cd吸收以及转运的若干实用技术,包括水分管理、钝化技术、淋洗技术、电动修复技术、植物修复技术、低累积水稻品种的选取以及叶面阻控技术,归纳并分析了各种技术的处理效果、作用机制和制约因素,提出了主要阻控技术的发展方向,指出构建区域高适配性综合技术模式的重要性,以期为稻田As-Cd复合污染治理和水稻安全生产提供参考.  相似文献   
939.
940.
This work presents an unconventional procedure for the recovery of spent Al-rich caustic soda solutions from the pickling of dies for the production of aluminium extrusions. Caustic soda was regenerated at roughly 70%, by precipitating aluminate, after addition of a silica source, in the form of zeolite A, a microporous material that is widely used in many technological sectors. It was shown that the process is reliable and can be repeated for several cycles, provided the concentration of the caustic soda solution is suitably restored. The by-product obtained, zeolite A, proved to be a high-grade material with performance as a cation exchanger and physical sorbent that is certainly comparable to that reported in literature (e.g., cation exchange capacity equal to 5.14 meq g(-1) vs. 5.48 meq g(-1) and water vapour adsorption capacity of 26.5% vs. 27.6% at 16 torr and 298 K). The economics of the process, although not examined yet, would appear generally favourable, considering that zeolite A is a valuable by-product which widely covers the costs for the recovery of the spent solutions. There are, therefore, significant prospects for the use of zeolite A, particularly as a builder in detergent formulation.  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