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   321篇
  免费   27篇
  国内免费   48篇
安全科学   14篇
环保管理   138篇
综合类   117篇
基础理论   62篇
污染及防治   27篇
评价与监测   14篇
社会与环境   22篇
灾害及防治   2篇
  2023年   6篇
  2022年   4篇
  2021年   8篇
  2020年   8篇
  2019年   10篇
  2018年   6篇
  2017年   11篇
  2016年   10篇
  2015年   12篇
  2014年   20篇
  2013年   23篇
  2012年   13篇
  2011年   20篇
  2010年   20篇
  2009年   13篇
  2008年   14篇
  2007年   33篇
  2006年   20篇
  2005年   12篇
  2004年   11篇
  2003年   7篇
  2002年   7篇
  2001年   10篇
  2000年   9篇
  1999年   8篇
  1998年   6篇
  1997年   4篇
  1996年   12篇
  1995年   7篇
  1994年   11篇
  1993年   3篇
  1992年   3篇
  1991年   2篇
  1990年   3篇
  1989年   7篇
  1988年   2篇
  1987年   2篇
  1986年   3篇
  1984年   2篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1979年   2篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1973年   2篇
  1971年   1篇
  1969年   1篇
排序方式: 共有396条查询结果,搜索用时 187 毫秒
1.
ABSTRACT: The use of nonparametric tests for monotonic trend has flourished in recent years to support routine water quality data analyses. The validity of an assumption of independent, identically distributed error terms is an important concern in selecting the appropriate nonparametric test, as is the presence of missing values. Decision rules are needed for choosing between alternative tests and for deciding whether and how to pre-process data before trend testing. Several data pre-processing procedures in conjunction with the Mann-Kendall tau and the Seasonal Kendall test (with and without serial correlation correction) are evaluated using synthetic time series with generated serial correlation and missing data. A composite test (pre-testing for serial correlation followed by one of two trend tests) is evaluated and was found to perform satisfactorily.  相似文献   
2.
Selecting Socio-Economic Metrics for Watershed Management   总被引:1,自引:0,他引:1  
The selection of social and economic metrics to document baseline conditions and analyze the dynamic relationships between ecosystems and human communities are important decisions for scientists, managers, and watershed citizens. A large variety of social and economic data is available but these have limited use without theoretical frameworks. In this paper, several frameworks for reviewing social-ecosystem relations are offered, namely social sanctions, sense of place, civic structure, and cultural differences. Underlying all of these frameworks are attitudes, beliefs, values, and norms that affect which questions are asked and which indicators are chosen. Much work and significant challenges remain in developing a standard set of spatially based socio-economic metrics for watershed management.  相似文献   
3.
方巍 《上海环境科学》2006,25(5):228-230
环境污染对环境产生的负价值与环境保护对环境产生的正价值相互作用、相互抵消的运动过程,体现了环境整体价值在人类经济社会活动影响下的具体演化模式。文章探讨了环境价值的循环途径、环境资源价值的模型,并对模型进行了具体分析,以期帮助人们提高对环境价值的认识。  相似文献   
4.
黄山风景区物质容量研究   总被引:11,自引:0,他引:11  
系统地分析了旅游区物质容量与其子容量之间的关系,根据黄山区风景区客流空间负荷特点,认为北海游览区是黄山风景区物质容量的“瓶照”最低水桶板原则,合理计算了黄山风景区物质容量;详细探讨了扩大黄山风景区物质容量的若干途径。  相似文献   
5.
/ Limit values are legal limits for the concentrations of substances in the environment. They must be agreed upon in a consensual procedure between science, economics/technology, and political forces. This is a crucial political precondition for their social acceptance. The arguments put forward to justify their expediency and numerical level are based not only on risk-benefit considerations but also on the aspect of the technical avoidability of direct and indirect exposure. The critical assessment of the direct benefit of specified exposures falls within the responsibility of economics/technology, whereas criteria for their potential adverse effects (direct and indirect) are provided by medicine/biochemistry and/or ecology. Within this concept, the avoidance of nonbeneficial-even if not openly adverse-exposure is the essential aim of environmental hygiene and should be promoted by politics/science. In general, society or segments thereof reject adverse, accept beneficial, and tolerate unavoidable exposure. Conflicts of interest arise when different groups of society simultaneously define a given exposure as being adverse, beneficial, and unavoidable. Therefore, from the viewpoint of society as a whole, an optimal exposure lies as far as reasonably achievable at a level lower than known or plausible adverse effect thresholds (as defined by toxicology or ecology). This optimal level of exposure must be determined using a transparent and, hence, public procedure.KEY WORDS: Legal limit values; Benefit threshold; Social acceptance; Social tolerability; Adverse effect threshold; Avoidable exposure; Tolerance threshold; Environmental hygiene  相似文献   
6.
九华山风景名胜区是山岳型宗教旅游地。通过对九华山风景区的实地调查,总结了该类旅游地的土地利用特点,即统一性和协调性、难以变更性、总量有限性,并进行了土地利用沿革、变更和影响方面的分析。利用层次分析法从生存指标、发展指标、社会指标、环境指标和智力指标5个方面对九华山风景区的土地利用进行了定量讨论,认为九华山风景区土地利用问题现阶段主要集中在九华街景区、花台景区和柯村景区。在此基础上,对九华山风景区土地的可持续利用提出了相应的对策。  相似文献   
7.
The present study focuses on the definition and assessment of overpressure threshold values for the damage to equipment caused by blast waves originated by primary accidental scenarios. A revision of literature data and of the available damage probability models was carried out. Threshold values were proposed for different categories of process equipment, taking into account either damage levels or release intensities following the loss of containment. Specific threshold values for domino effect were also proposed.  相似文献   
8.
中质旅游景区开发初探   总被引:1,自引:0,他引:1  
中质景区是指旅游综合质量中等的景区.开发中质景区可以增加目的地供给、优化旅游目的地结构、分流优质景区客流.以四川雅安碧峰峡景区为例,在分析该类型景区优劣势的基础上,对其在旅游项目设计、资金筹措、客源市场、产品设计、市场营销等方面提出了对策.同时指出,我国中质旅游景区开发中存在着资源价值评价不准确、资源破坏严重等误区,以期在旅游实践中提高中质旅游景区的开发质量.  相似文献   
9.
A vibrant debate about the future direction of biodiversity conservation centers on the merits of the so‐called new conservation. Proponents of the new conservation advocate a series of positions on key conservation ideas, such as the importance of human‐dominated landscapes and conservation's engagement with capitalism. These have been fiercely contested in a debate dominated by a few high‐profile individuals, and so far there has been no empirical exploration of existing perspectives on these issues among a wider community of conservationists. We used Q methodology to examine empirically perspectives on the new conservation held by attendees at the 2015 International Congress for Conservation Biology (ICCB). Although we identified a consensus on several key issues, 3 distinct positions emerged: in favor of conservation to benefit people but opposed to links with capitalism and corporations, in favor of biocentric approaches but with less emphasis on wilderness protection than prominent opponents of new conservation, and in favor of the published new conservation perspective but with less emphasis on increasing human well‐being as a goal of conservation. Our results revealed differences between the debate on the new conservation in the literature and views held within a wider, but still limited, conservation community and demonstrated the existence of at least one viewpoint (in favor of conservation to benefit people but opposed to links with capitalism and corporations) that is almost absent from the published debate. We hope the fuller understanding we present of the variety of views that exist but have not yet been heard, will improve the quality and tone of debates on the subject.  相似文献   
10.
Understanding human perspectives is critical in a range of conservation contexts, for example, in overcoming conflicts or developing projects that are acceptable to relevant stakeholders. The Q methodology is a unique semiquantitative technique used to explore human perspectives. It has been applied for decades in other disciplines and recently gained traction in conservation. This paper helps researchers assess when Q is useful for a given conservation question and what its use involves. To do so, we explained the steps necessary to conduct a Q study, from the research design to the interpretation of results. We provided recommendations to minimize biases in conducting a Q study, which can affect mostly when designing the study and collecting the data. We conducted a structured literature review of 52 studies to examine in what empirical conservation contexts Q has been used. Most studies were subnational or national cases, but some also address multinational or global questions. We found that Q has been applied to 4 broad types of conservation goals: addressing conflict, devising management alternatives, understanding policy acceptability, and critically reflecting on the values that implicitly influence research and practice. Through these applications, researchers found hidden views, understood opinions in depth and discovered points of consensus that facilitated unlocking difficult disagreements. The Q methodology has a clear procedure but is also flexible, allowing researchers explore long‐term views, or views about items other than statements, such as landscape images. We also found some inconsistencies in applying and, mainly, in reporting Q studies, whereby it was not possible to fully understand how the research was conducted or why some atypical research decisions had been taken in some studies. Accordingly, we suggest a reporting checklist.  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