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   445篇
  免费   55篇
  国内免费   37篇
安全科学   83篇
废物处理   20篇
环保管理   110篇
综合类   211篇
基础理论   42篇
污染及防治   12篇
评价与监测   32篇
社会与环境   23篇
灾害及防治   4篇
  2024年   5篇
  2023年   10篇
  2022年   14篇
  2021年   23篇
  2020年   25篇
  2019年   22篇
  2018年   13篇
  2017年   20篇
  2016年   27篇
  2015年   28篇
  2014年   19篇
  2013年   31篇
  2012年   43篇
  2011年   43篇
  2010年   25篇
  2009年   39篇
  2008年   26篇
  2007年   18篇
  2006年   24篇
  2005年   18篇
  2004年   17篇
  2003年   12篇
  2002年   5篇
  2001年   6篇
  2000年   3篇
  1999年   6篇
  1998年   5篇
  1997年   1篇
  1996年   2篇
  1995年   1篇
  1993年   1篇
  1992年   1篇
  1989年   1篇
  1987年   2篇
  1978年   1篇
排序方式: 共有537条查询结果,搜索用时 15 毫秒
151.
In this study, we investigate whether traditional swidden agriculture on nutrient-poor tropical soils can sustainably support a growing indigenous population within Manu National Park, Peru. Based on interviews with 50 Matsigenka farmers, as well as GPS mapping and field visits, we established the location and size of all 124 swidden gardens cultivated in 2000 and 2001. Using a GIS-based soil map of Manu Park, we identify the total extent of potential arable land (1) throughout the park zones currently available for Matsigenka habitation, and (2) within the vicinity of the two study communities. Taking into account current per capita garden size, cultivation and fallow practices, we calculate the maximum human carrying capacity of swidden agriculture for (1) all available park zones and (2) the immediate vicinity of the two current communities. Even given the second, highly limited scenario, the sustainable human carrying capacity is estimated to be 2,138 individuals, which is far higher than the current population of about 420 people. Thus, arable land does not appear to be a limiting factor for the growth of the indigenous population in Manu Park at the current time. Other possible limiting factors for population growth are identified and discussed. We conclude that a conservation policy of population stabilization around the current settlements is viable in that it will not result in reduced resource availability over the next few decades, and that the challenge is to identify and mitigate the forces causing population fissioning and spread. Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   
152.
化工园区安全规划发展历史回顾   总被引:9,自引:3,他引:6  
系统回顾了化工园区安全规划的发展历史,简要介绍不同国家化工园区安全规划的分区制思想以及相应的法律法规要求。以1970年代中期为界,化工园区安全规划历史大体可分为两个阶段。第一阶段基本确立了土地利用规划分区制的思想,风险越大,工业活动就建设在距人居环境越远的区域。但由于没有量化的理论和方法支持,因此,不能准确确定合适的安全距离。第二阶段从科学的土地利用规划开始并得益于定量风险评价的日趋成熟和广泛使用。由于能够定量计算出比较准确的安全距离和可承受风险,因而可以更好地进行工业活动分区和安全规划。目前单纯基于风险的安全规划暴露出一定的局限性,人们不仅要考虑工业活动的潜在风险,而且需要综合考虑经济、社会、环境、生态以及人文历史等诸多因素,因此,急需研究能够综合处理复杂问题的安全规划理论和方法。回顾历史并分析和比较,笔者认为,科学的安全规划是预防重特大事故的根本措施之一,健全的法制基础是实施安全规划的必要保障,风险评价技术是实施安全规划的有力武器。取得的研究成果对我国化工园区以及其他工业园区的建设具有一定的借鉴和启迪作用。  相似文献   
153.
工业园区水污染防治的问题与对策探讨   总被引:1,自引:1,他引:0       下载免费PDF全文
随着快速工业化发展,尤其是新建工业项目"入园进区"的推进,工业园区水污染防治越来越成为工业污染防治的重中之重。本文通过从园区准入、适用标准、管理体系等方面对当前工业园区水污染防治中的问题的梳理,对工业园区系统化的工业园区环境行政管理体系进行探讨,研究建议:在园区设立时,应突出区域上资源、能源、环境三元优化与统一,园区企业入园突出环境准入尤其是有利于园区的生态化与循环化改造;在园区企业水污染防治中,应探索园区企业协同治污的差异化排放标准,建立全过程控制水污染防治路线;在环境管理体制创新中,应以排污许可管理为主线,构建园区环境管理相关方协同的系统管理机制。  相似文献   
154.
In Rocky Mountain National Park (RMNP), aspen (Populus tremuloides Michx.) has been observed to be declining on elk (Cervus elaphus nelsoni) winter range for many decades. To support elk management decisions, the SAVANNA ecosystem model was adapted to explore interactions between elk herbivory and aspen dynamics. The simulated probability of successful vegetative regeneration for senescent aspen stands declines sharply when elk densities reach levels of 3–5 elk/km2, depending on model assumptions for the seasonal duration of elk foraging activities. For aspen stands with a substantial component of younger trees, the simulated regeneration probability declines more continuously with increasing elk density, dropping below 50% from densities at 8–14 elk/km2.At the landscape scale, simulated aspen regeneration probability under a scenario of extensive seasonal use was little affected by elk population level, when this level was above 300–600 elk (25%–50% current population) over the ca. 107 km2 winter range. This was because elk distribution was highly aggregated, so that a high density of elk occupied certain areas, even at low population levels overall. At approximately current elk population levels (1000–1200 elk), only 35%–45% of senescent aspen stands are simulated as having at least a 90% probability of regeneration, nearly all of them located on the periphery of the winter range. Successful management for aspen persistence on core winter range will likely require some combination of elk population reduction, management of elk distribution, and fencing to protect aspen suckers from elk browsing.  相似文献   
155.
Environmental management systems (EMSs), such as International Organization for Standardization (ISO) 14001, can be used as a tool in China by industrial park managers to improve their environmental performance. This article uses the case of the Dalian Economic and Technological Development Zone (DETDZ) to show how to establish a comprehensive environmental management system (CEMS) according to the ISO 14001 standard at the industrial park level by considering local realities. The particularly interesting feature of this case study is the use of a CEMS (in this case, ISO 14001) by the administrative group of the DETDZ to develop a more comprehensive approach to the wide range of environmental issues that they face in running the zone. In essence the goal is to address many of the issues at the level of the zone. The incentives, benefits, and barriers associated with implementing ISO 14001 are described. However, implementation of an EMS should not be thought of as the ultimate objective for an industrial parks environmental management. The next steps include encouraging further public participation and taking an integrated approach leading to an industrial ecosystem, which can realize better environmental performance at the industrial park level. Yong Geng is currently a Ph.D. candidate at Dalhousie University. Raymond Côté is a professor at Dalhousie University.  相似文献   
156.
This paper appraises, in the context of the current debate concerning national parks for Scotland, factors that may have contributed to the achievement of national park purposes in England and Wales. Voluntary support, presumptions and resources are seen as crucial to the achievement of those purposes; while the few extra powers available to the national park authorities and the plan making process are seen to be of some importance. In contrast, it is argued that the much‐debated nature of the administrative authority has had little effect on the extent to which park purposes are achieved.  相似文献   
157.
Human-influenced changes in the diversity and abundance of native wildlife in a southern boreal forest area, which became a national park in 1975, are used to develop working hypotheses for predicting and subsequently measuring the effects of disturbance or restoration programs on groups of interacting species. Changes from presettlement conditions began with early 1900 hunting, which eliminated woodland caribou (Rangifer tarandus) and elk (Cervus elaphus), and reduced moose (Alces alces) to the low numbers which still persist. Increases in white-tailed deer (Odocoileus virginianus), as these other cervid species became less abundant or absent, provided enough alternative food to sustain the system's carnivores until plant succession on previously burned or logged areas also caused deer to decline. With increased competition for reduced food, carnivore species also became less abundant or absent and overexploited some prey populations. The abilities of interacting species to maintain dynamically stable populations or persist varied with their different capacities to compensate for increased exploitation or competition. These relationships suggested a possible solution to the problem of predicting the stability of populations in disturbed systems. For the 1976–1985 period, a hypothesis that the increased protection of wildlife from exploitation in a national park would restore a more diverse, abundant, and productive fauna had to be rejected.  相似文献   
158.
Japan’s national park system constitutes a potentially viable mechanism for securing local community participation and building stakeholder consensus for sustainable park management, although the potential of this system is yet to be fully maximized. This article gives an overview of the system of protecting natural resources in Japan, focusing on the national park system. Parks are managed by zoning and regulation, which is unique in that land is not “set aside” for nature conservation, but designated as national park wherever the need to preserve “scenic beauty” has been recognized, regardless of land ownership or land use. Although resource conservation under this system has been problematic, it has advantages, especially in terms of community participation. This article demonstrates that in order to reach the system’s potential, the park authority must act as coordinator of stakeholders and facilitator of bottom-up approaches to decision-making. In order to do this, steps that must be taken include the following: identifying the various stakeholders in park management and defining the “local community”; clarifying the roles and responsibilities of each stakeholder; and supporting consensus-building among stakeholders regarding the objectives and long-term vision of each park. By taking these steps, it would be possible to build a park management system that overrides government boundaries and involves local communities. This will enable the park authority to address the challenges facing Japan’s complex system of conserving natural resources, and move towards sustainable management of natural resources in Japan.  相似文献   
159.
Governance refers to the interactions among structures, processes, and traditions that determine direction, how power is exercised, and how the views of citizens or stakeholders are incorporated into decision-making. Governance is now recognized as a critical aspect of effective conservation and is a prominent part of the Convention on Biological Diversity’s work program on protected areas. This study reports on a global survey to assess changes in governance of protected area systems between 1992 and 2002 based on responses from 41 countries. Results indicate that substantial changes have taken place with overall trends towards increased participation of more stakeholders, greater use of formal accountability mechanisms, and a wider range of participatory techniques. Many of these changes are supported by legislative and policy requirements and 75% of respondents reported changes in legislation over the past decade. Protected areas are becoming more influenced by global forces. A majority of respondents reported increased involvement of the private sector. Funding is coming from a broader range of sources, with a smaller proportion of income coming from government sources in 2002. Absolute funding amounts have increased, but almost two-thirds report that budgets fall short of requirements. Almost 90% of respondents felt that protected area governance had improved over the last decade; 67% felt that this had also led to improved management effectiveness. Respondents felt that secure funding, capacity building, and increased community involvement were the main governance needs for the future.  相似文献   
160.
本文以新疆石河子国家生态工业(造纸)园区的设计为例.运用产业生态学理论,深入系统地分析了生态工业园区的系统构成、工业共生关系以及生态工业链网结构.为全新型生态工业园区的设计及其运行提出了切实可行的建议。  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