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   6989篇
  免费   584篇
  国内免费   1286篇
安全科学   1319篇
废物处理   103篇
环保管理   1044篇
综合类   3958篇
基础理论   792篇
污染及防治   377篇
评价与监测   593篇
社会与环境   318篇
灾害及防治   355篇
  2024年   37篇
  2023年   141篇
  2022年   193篇
  2021年   240篇
  2020年   266篇
  2019年   234篇
  2018年   217篇
  2017年   263篇
  2016年   333篇
  2015年   373篇
  2014年   417篇
  2013年   489篇
  2012年   543篇
  2011年   632篇
  2010年   416篇
  2009年   459篇
  2008年   356篇
  2007年   484篇
  2006年   423篇
  2005年   339篇
  2004年   261篇
  2003年   263篇
  2002年   210篇
  2001年   195篇
  2000年   196篇
  1999年   162篇
  1998年   134篇
  1997年   125篇
  1996年   77篇
  1995年   99篇
  1994年   50篇
  1993年   59篇
  1992年   36篇
  1991年   26篇
  1990年   14篇
  1989年   10篇
  1988年   10篇
  1987年   11篇
  1986年   11篇
  1985年   6篇
  1984年   9篇
  1983年   3篇
  1982年   10篇
  1981年   11篇
  1980年   5篇
  1979年   2篇
  1978年   3篇
  1977年   3篇
  1975年   1篇
  1973年   1篇
排序方式: 共有8859条查询结果,搜索用时 156 毫秒
741.
Over recent decades, public participation in technology assessment has spread internationally as an attempt to overcome or prevent societal conflicts over controversial technologies. One outcome of this new surge in public consultation initiatives has been the increased use of participatory consensus conferences in a number of countries. Existing evaluations of consensus conferences tend to focus on the modes of organization, as well as the outcomes, both procedural and substantial, of the conferences they examine. Such evaluations seem to rest on the assumption that this type of procedure has universally agreed goals and meanings, and that therefore consensus conferences can readily be interpreted and applied across national boundaries. This article challenges this approach to consensus conferences. The core of the article is a study of national differences in ideas about what constitutes legitimate goals for participatory arrangements. The study looks at three consensus conferences on GMOs, which took place in France, Norway, and Denmark. Drawing on this study, the article discusses the ways in which interpretations of the concept of participation; the value attributed to lay knowledge vs. technical expertise; as well as ideas about the role of the layperson, are all questions that prompt entirely different answers from country to country. Further, the article analyses these national differences within a theoretical framework of notions of democratic legitimacy.  相似文献   
742.
民航安全风险定量评价模型研究   总被引:3,自引:3,他引:3  
在对民航风险评价的现状和常用的定量风险评价方法进行分析的基础上,建立民航安全风险定量评价模型。在计算风险的可能性时,不仅考虑了风险的历史发生概率,而且利用风险发生概率影响因素所发生的变化对风险的历史发生概率进行修正,从而得出在当前情况下风险的发生概率,并且首次提出指数型权重的概念;在计算风险的后果时,考虑风险的直接损失和间接损失,并通过计算多种可能后果的期望的形式,综合考虑多种可能的后果情况;通过上述的可能性和严重性从而达到对安全风险进行定量评价的目的。最后,给出了一个算例,其结果表明该模型具有很强的实用性。  相似文献   
743.
基于事故理论的城市轨道交通风险评价模型研究   总被引:1,自引:0,他引:1  
笔者分析了城市轨道交通事故,在分析我国其他行业事故分类的基础上,确定城市轨道交通事故分类标准,即重大事故、大事故、险性事故和一般事故,并将不同事故分类情况及专家判断评分,按事故的大小不同换算成可以计算的计算尺度,根据事故种类不同计算出事故折算因子,根据风险理论的评价方法,建立了地铁风险评价模型,对地铁的危险性进行量化定级,并通过具体实例进行综合分析评价,该风险评价模型具有一定的工程意义。  相似文献   
744.
空中交通管制雷达管制训练分类考核方法研究   总被引:1,自引:0,他引:1  
分析当前我国管制员雷达培训考核环节中存在的问题,提出一种新的雷达管制培训的考核方法——检查单式考核,根据管制过程所涉及的各个环节以及航空器在空中的运行状态,对雷达管制培训实施分类考核。并结合一个进近雷达管制考核表的实例,分析其检查单式考核表的设计思想,详细说明其考核表记录和考核结果量化的步骤和方法。  相似文献   
745.
煤矿危险源辨识与多层评价分级研究   总被引:1,自引:0,他引:1  
根据煤炭系统生产的复杂特点,提出了采用系统科学的方法,对煤炭生产进行系统的单元划分,采用安全系统科学辨识的方法对危险源进行辨识.在此基础上,提出利用层次分析法和模糊动态评判的方法对危险源进行初次分级,根据危险源的耦合特性,提出二次动态分级的方法,对初次分级进行调整,确定危险源科学、合理的级别,并提出了进一步现实性评价的建议.  相似文献   
746.
现有评价方法在油气长输管道工程安全评价中的应用   总被引:1,自引:0,他引:1  
油气长输管道工程的安全评价工作正在成为新建及在役管道安全运行的保障。针对目前国内已开展的油气长输管道工程安全评价现状,结合自身安全评价工作实践,对现有评价方法在油气长输管道工程安全评价中的应用进行了讨论,并提出相应建议。  相似文献   
747.
Abstract: The U.S. Federal Emergency Management Agency (FEMA) flood maps depict the 100‐year recurrence interval floodplain boundary as a single line. However, because of natural variability and model uncertainty, no floodplain extents can be accurately defined by a single line. This article presents a new approach to floodplain mapping that takes advantage of accepted methodologies in hydrologic and hydraulic analysis while including the effects of uncertainty. In this approach, the extents of computed floodplain boundaries are defined as a continuous map of flood probabilities, rather than as a single line. Engineers and planners can use these flood probability maps for viewing the uncertainty of a floodplain boundary at any recurrence interval. Such a flood probability map is a useful tool for visualizing the uncertainty of a floodplain boundary and represents greater honesty in engineering technologies that are used for flood mapping. While institutional barriers may prevent adoption of such definitions for use in graduated flood insurance rates (as most other insurance industries use to account for relative risks), the methods open the door technically to such a reality.  相似文献   
748.
Abstract: There is a significant need for a science‐based approach to interpret water‐monitoring data and to facilitate the rapid transfer of information to water resource managers and the general public. The water quality Index (WQI) is defined as a single numeric score that describes the surface water quality condition at a particular time and location. The objective of this paper is to describe the WQI concept and the approach for developing an ecoregion‐specific standardized WQI that meets the needs described above. The premise of the proposed WQI is based on categorizing scientifically documented aquatic life responses to changes in instream water chemistry. The method uses an aggregated procedure that matches the entire range of standardized probable biological responses to standardized narrative water quality evaluation categories and standardized rank score categories. The calculation of WQI and decision‐making process are performed within an Excel spreadsheet software program. The article includes examples of the proposed WQI applications that could enhance effective water resource management and facilitate timely communication of water quality conditions to water resource managers and the general public.  相似文献   
749.
ABSTRACT: During the past 15 years a number of methods have been developed that purport to evaluate the amenity values of rivers. Most methods are designed to identify the physical, biological, cultural, and esthetic features of a river or river corridor that are conducive to recreation, preservation, and other amenity values. This paper reviews and comments on 13 methods that evaluate amenity values. The methods are reviewed and discussed under three general headings: River Recreation Potential Evaluation, River Esthetic Evaluation, and River Preservation Evaluation. A final section of the paper identifies areas where improvements and further research are needed.  相似文献   
750.
Bogs are of interest to outdoor recreationists, but little information exists concerning how recreation resource managers might manage these areas to enhance visitor benefits. This study evaluates bog visitor characteristics and experiences, visual preferences, and reasons for visiting. Implications for recreational resource management of bogs include the location and design of boardwalk trails and management of understory vegetation to meet the visual preferences and motives of bog visitors.  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