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   990篇
  免费   94篇
  国内免费   114篇
安全科学   122篇
废物处理   11篇
环保管理   343篇
综合类   367篇
基础理论   161篇
污染及防治   43篇
评价与监测   35篇
社会与环境   61篇
灾害及防治   55篇
  2023年   9篇
  2022年   21篇
  2021年   30篇
  2020年   24篇
  2019年   35篇
  2018年   26篇
  2017年   35篇
  2016年   33篇
  2015年   36篇
  2014年   38篇
  2013年   68篇
  2012年   44篇
  2011年   77篇
  2010年   50篇
  2009年   53篇
  2008年   46篇
  2007年   44篇
  2006年   70篇
  2005年   46篇
  2004年   37篇
  2003年   38篇
  2002年   49篇
  2001年   32篇
  2000年   45篇
  1999年   42篇
  1998年   20篇
  1997年   15篇
  1996年   22篇
  1995年   19篇
  1994年   15篇
  1993年   11篇
  1992年   21篇
  1991年   3篇
  1990年   2篇
  1989年   2篇
  1988年   3篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1980年   2篇
  1979年   2篇
  1978年   4篇
  1977年   3篇
  1976年   1篇
  1975年   3篇
  1973年   1篇
  1972年   4篇
  1971年   7篇
排序方式: 共有1198条查询结果,搜索用时 15 毫秒
111.
Australian governments have sought to invest in irrigation infrastructure to improve the efficiency of water delivery to rural properties and improve water supply and on-farm efficiency. A programme of rationalising irrigation infrastructure has attracted criticism and doubts about its likely success. Attitude theory in the form of the Reasoned Action Model was applied to understand the intentions of landowners to connect to a ‘modernised’ irrigation system. Attitudes towards connecting to the system, social norms and perceptions of control over the behaviour provided an explanation of intentions to connect. Actual financial capability and other variables were important in discriminating a group of landowners who had already connected to the modernised system from farmers who had not.  相似文献   
112.
随着近几年滩涂围垦工程的进行,为了协调围垦开发与生态环境保护之间的矛盾,生态型围垦的理念应运而生。本文对"生态型围垦"的内涵进行了深入辨析,提出了沿海滩涂生态型围垦概念模型,针对围垦工程规划前期、工程实施和运行管理3个阶段的特点,从管理、环境和生态3个方面提出相应指标,初步构架了生态型围垦指标体系,为沿海滩涂围垦的可持续及匡围区域生态环境管理提供技术支撑。  相似文献   
113.
Abstract: Unintended effects of recreational activities in protected areas are of growing concern. We used an adaptive‐management framework to develop guidelines for optimally managing hiking activities to maintain desired levels of territory occupancy and reproductive success of Golden Eagles (Aquila chrysaetos) in Denali National Park (Alaska, U.S.A.). The management decision was to restrict human access (hikers) to particular nesting territories to reduce disturbance. The management objective was to minimize restrictions on hikers while maintaining reproductive performance of eagles above some specified level. We based our decision analysis on predictive models of site occupancy of eagles developed using a combination of expert opinion and data collected from 93 eagle territories over 20 years. The best predictive model showed that restricting human access to eagle territories had little effect on occupancy dynamics. However, when considering important sources of uncertainty in the models, including environmental stochasticity, imperfect detection of hares on which eagles prey, and model uncertainty, restricting access of territories to hikers improved eagle reproduction substantially. An adaptive management framework such as ours may help reduce uncertainty of the effects of hiking activities on Golden Eagles.  相似文献   
114.
Watershed analysis and watershed management are developing as tools of integrated ecological and economic study. They also assist decision-making at the regional scale. The new technology and thinking offered by the advent of the Internet and the World Wide Web is highly complementary to some of the goals of watershed analysis. Services delivered by the Web are open, interactive, fast, spatially distributed, hierarchical and flexible. The Web offers the ability to display information creatively, to interact with that information and to change and modify it remotely. In this way the Internet provides a much-needed opportunity to deliver scientific findings and information to stakeholders and to link stakeholders together providing for collective decision-making. The benefits fall into two major categories: methodological and educational. Methodologically the approach furthers the watershed management concept, offering an avenue for practical implementation of watershed management principles. For educational purposes the Web is a source of data and insight serving a variety of needs at all levels. We use the Patuxent River case study to illustrate the web-based approach to watershed management. A watershed scale simulation model is built for the Patuxent area and it serves as a core for watershed management design based on web applications. It integrates the knowledge available for the Patuxent area in a comprehensive and systematic format, and provides a conceptual basis for understanding the performance of the watershed as a system. Moreover, the extensive data collection and conceptualisation required within the framework of the modeling effort stimulates close contact with the environmental management community. This is further enhanced by offering access to the modeling results and the data sets over the Web. Additional web applications and links are provided to increase awareness and involvement of stakeholders in the watershed management process. We argue that it is not the amount and quality of information that is crucial for the success of watershed management, but how well the information is disseminated, shared and used by the stakeholders. In this respect the Web offers a wealth of opportunities for the decision-making process, but still to be answered are the questions at what scale and how widely will the Web be accepted as a management tool, and how can watershed management benefit from web applications.  相似文献   
115.
以宁波市象山县水湖涂名优水产围海养殖工程为研究对象,通过构建生态服务价值损害评估指标体系,分析了围海养殖区的生态损害特征,并基于海域自我恢复能力,研究了围海养殖工程的生态补偿标准和资源恢复周期。结果显示:(1)名优水产围海养殖工程造成的生态损害总价值为318.90万元/a,单位面积损害价值为3.20万元/hm2·a。生态损害主要以生态服务型为主,占总量比例为53.54%。(2)生物资源型损害类别中,潮间带生物损害价值最大,为59.71万元,其次为紫菜养殖和鱼卵、仔鱼,二者损害价值量相当,占总量比例均为13.55%,底栖生物和游泳生物价值损失则均较小。(3)生态服务型损害类别中,一级类别主要以调节服务价值为主,占总量比例为32.56%。二级损害类别中,废弃物处理损害价值最大,为71.77万元,休闲娱乐损害价值也较大,占总量比例为12.80%,其他类型则价值损失较小。(4)名优水产围海养殖工程基于海域自我恢复能力的生态补偿标准为280.90万元/a,单位面积补偿价值为2.82万元/hm2·a,对比生态损害价值确定的补偿标准,总量减少11.92%。项目施工结束后,近岸滩涂恢复速度为4.6320 hm2/a,约13年后新围大堤附近滩涂将恢复到围海前的基线水平。  相似文献   
116.
ABSTRACT: This work begins by defining rational water use, and then discusses important factors that most strongly influence it. A general model is then developed to enable factories to quantify the ratio of rational industrial water reuse based on the least cost method. The model is established to minimize the cost of water with reference to gross water use and three subsystems ‐ the intake, reuse, and discharge of industrial water. Discharge cost is determined using data from a 1997 survey of 38 factories, and reuse costs are ranked and expressed by a step function. The model is verified using data from a typical semiconductor factory in northern Taiwan's Hsinchu Science Based Industrial Park, whose effective rational water reuse ratio is about 38 percent. A sensitivity analysis shows that improving water reuse technology is the most important factor in determining the rational water reuse ratio, and the price of water is the second most important. When water costs over NT$30 (New Taiwan Dollar, US$1 = NT$34) per cubic meter, increasing reuse becomes significant. The model provides a step towards the scientific management of industrial water.  相似文献   
117.
基于整体开发管理的国际河流决策支持系统   总被引:1,自引:0,他引:1  
基于国际河流开发管理的现状,分析国际河流整体开发管理理论的演进。得出整体开发管理决策实施的原则及思路:流域开发管理要以流域边界为界,将整个水系自然联系的区域作为不可分割的整体,进行统一权衡,突出共同利益,流域内开发与流域外开发相结合。以建立多层次的国际合作机构。对国际河流决策支持系统进行设计,即以国际河流流域为体系,各国国内流域测点为单元。国际流域综合协调委员会为决策支持中心、各国流域机构委员会为决策支持分中心。并研究系统的公用信息平台建设,信息开发、管理与维护。河流水资源、水环境实时监控等技术支持系统。实证分析澜沧江-湄公河流域决策支持系统的建设。并指出国际河流水资源的开发与管理,水权等问题有待进一步深入研究。  相似文献   
118.
Achieving Integrative, Collaborative Ecosystem Management   总被引:3,自引:0,他引:3  
Abstract:  Although numerous principles have been identified as being important for successfully integrating social and ecological factors in collaborative management, few authors have illustrated how these principles are used and why they are effective. On the basis of a review of the ecosystem management and collaboration literature, we identified eight factors important for integrative, collaborative ecosystem management—integrated and balanced goals, inclusive public involvement, stakeholder influence, consensus group approach, collaborative stewardship, monitoring and adaptive management, multidisciplinary data, and economic incentives.We examined four cases of successful ecosystem management to illustrate how the factors were incorporated and discuss the role they played in each case's success. The cases illustrate that balancing social and ecosystem sustainability goals is possible. Collaborative efforts resulted in part from factors aimed at making plans economically feasible and from meaningful stakeholder participation in ongoing management. It also required participation in monitoring programs to ensure stakeholder interests were protected and management efforts were focused on agreed-upon goals. Data collection efforts were not all-inclusive and systematic; rather, they addressed the ecological, economic, and social aspects of key issues as they emerged over time. Economic considerations appear to be broader than simply providing economic incentives; stakeholders seem willing to trade some economic value for recreational or environmental benefits. The cases demonstrate that it is not idealistic to believe integrative, collaborative ecosystem management is possible in field applications.  相似文献   
119.
本文针对国内外宏观环境决策中存在的问题,阐述了以科学研究为基础的宏观环境决策支持系统的作用,分析了决策观点和思维的多样性对宏观环境决策的意义,探讨了宏观环境决策与环境基础学科建设的关系。  相似文献   
120.
洞庭湖滩地围垦及其对生态环境的影响   总被引:19,自引:4,他引:15  
本文研究了建国以来洞庭湖区围垦利用方式及动态变化,分析了湖泊滩地浮涨,围垦利用与泥沙沉积的双重循环影响关系,在此基础上探讨了湖滩地围垦利用对生态环境的影响以及对湖滩地利用应采取的对策措施。  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