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   7182篇
  免费   240篇
  国内免费   576篇
安全科学   425篇
废物处理   169篇
环保管理   1576篇
综合类   3274篇
基础理论   679篇
环境理论   22篇
污染及防治   556篇
评价与监测   701篇
社会与环境   543篇
灾害及防治   53篇
  2024年   1篇
  2023年   62篇
  2022年   77篇
  2021年   125篇
  2020年   239篇
  2019年   124篇
  2018年   124篇
  2017年   201篇
  2016年   224篇
  2015年   225篇
  2014年   306篇
  2013年   419篇
  2012年   368篇
  2011年   537篇
  2010年   324篇
  2009年   483篇
  2008年   382篇
  2007年   443篇
  2006年   414篇
  2005年   261篇
  2004年   253篇
  2003年   304篇
  2002年   257篇
  2001年   255篇
  2000年   265篇
  1999年   229篇
  1998年   189篇
  1997年   187篇
  1996年   123篇
  1995年   104篇
  1994年   106篇
  1993年   103篇
  1992年   64篇
  1991年   41篇
  1990年   24篇
  1989年   22篇
  1988年   15篇
  1987年   13篇
  1986年   17篇
  1985年   16篇
  1984年   19篇
  1983年   7篇
  1982年   15篇
  1981年   8篇
  1980年   4篇
  1979年   1篇
  1978年   12篇
  1977年   5篇
  1974年   1篇
排序方式: 共有7998条查询结果,搜索用时 31 毫秒
951.
Lu J  Wu J  Fu Z  Zhu L 《Environmental management》2007,40(6):823-830
The invasion of water hyacinth (Eichhornia crassipes) has resulted in enormous ecological and economic consequences worldwide. Although the spread of this weed in Africa, Australia, and North America has been well documented, its invasion in China is yet to be fully documented. Here we report that since its introduction about seven decades ago, water hyacinth has infested many water bodies across almost half of China’s territory, causing a decline of native biodiversity, alteration of ecosystem services, deterioration of aquatic environments, and spread of diseases affecting human health. Water hyacinth infestations have also led to enormous economic losses in China by impeding water flows, paralyzing navigation, and damaging irrigation and hydroelectricity facilities. To effectively control the rampage of water hyacinth in China, we propose a sustainability science-based management framework that explicitly incorporates principles from landscape ecology and Integrated Pest Management. This framework emphasizes multiple-scale long-term monitoring and research, integration among different control techniques, combination of control with utilization, and landscape-level adaptive management. Sustainability science represents a new, transdisciplinary paradigm that integrates scientific research, technological innovation, and socioeconomic development of particular regions. Our proposed management framework is aimed to broaden the currently dominant biological control-centered view in China and to illustrate how sustainability science can be used to guide the research and management of water hyacinth.  相似文献   
952.
Copper is the biocide of choice for present-day antifouling (AF) paints. It is also a major source of copper loading in to the marine environment and, as such, might cause local copper levels to exceed water quality criteria. The present study is multifaceted and looks into the overall impact of copper-based AF paints on copper concentrations along a 64-km stretch of the Indian River Lagoon and at Port Canaveral, Florida. This preliminary study is one of the first to outline issues and present background evidence on the current status of copper and copper-based AF usage in Florida and to address the need for management. Previous measurements of copper levels in these waters show a history of copper contamination close to marinas, boatyards, and at Port Canaveral that often exceed state and federal water quality standards. Further, we estimate that the total annual copper input into the Indian River Lagoon is between 1.7 tons/year (sailboats) and 2.1 tons/year (powerboats) from boats in 14 marinas. We estimate the copper input into Port Canaveral to be about 1.4 tons/year from seven cruise ships. A brief survey of marina operators and boat owners revealed attitudes and practices associated with AF paint usage that ranged from excellent to inferior. Management recommendations are made for a proactive approach to improving AF paint selection and application, assessing the environmental status of copper, and redefining existing management practices for sustainable AF paint usage and environmental health.  相似文献   
953.
This Φ Ψ study of environmental equity uses secondary quantitative data to analyze socioeconomic disparities in environmental conditions in the Rijnmond region of the Netherlands. The disparities of selected environmental indicators—exposure to traffic noise (road, rail, and air), NO2, external safety risks, and the availability of public green space—are analyzed both separately and in combination. Not only exposures to environmental burdens (“bads”) were investigated, but also access to environmental benefits (“goods”). Additionally, we held interviews and reviewed documents to grasp the mechanisms underlying the environmental equity situation, with an emphasis on the role of public policy. Environmental equity is not a priority in public policy for the greater Rotterdam region known as the Rijnmond region, yet environmental standards have been established to provide a minimum environmental quality to all local residents. In general, environmental quality has improved in this region, and the accumulation of negative environmental outcomes (“bads”) has been limited. However, environmental standards for road traffic noise and NO2 are being exceeded, probably because of the pressure on space and the traffic intensity. We found an association of environmental “bads” with income for rail traffic noise and availability of public green space. In the absence of regulation, positive environmental outcomes (“goods”) are mainly left up to market forces. Consequently, higher-income groups generally have more access to environmental “goods” than lower-income groups.  相似文献   
954.
This paper aims to identify the factors underlying farmers' propensity to participate in organic farming programmes in a Romanian rural region that confronts non-point source pollution. For this, we employ structural equation modelling with latent variables using a specific data set collected through an agri-environmental farm survey in 2001. The model includes one 'behavioural intention' latent variable ('propensity to participate in organic farming programmes') and five 'attitude' and 'socio-economic' latent variables ('socio-demographic characteristics', 'economic characteristics', 'agri-environmental information access', 'environmental risk perception' and 'general environmental concern'). The results indicate that, overall, the model has an adequate fit to the data. All loadings are statistically significant, supporting the theoretical basis for assignment of indicators for each latent variable. The significance tests for the structural model parameters show 'environmental risk perception' as the strongest determinant of farmers' propensity to participate in organic farming programmes.  相似文献   
955.
This article discusses environmental sustainability in aquaculture and its contribution to poverty alleviation, based on field studies in Sri Lanka and the Philippines. The aquaculture practices studied are the monoculture of the black tiger prawn (Penneaus monodon) and milkfish (Chanos chanos) and the polyculture of the two species together with the mud crab (Scylla serrata). Factors affecting economic viability, social equity and environmental impacts in aquaculture are discussed and used to illuminate local and regional differences between aquaculture in Sri Lanka and the Philippines. Findings indicate that the most significant difference is the level of participation by local people (i.e., people originating ≤10 km away from the farm location). In the Philippines, 84 % of the people involved in aquaculture are locals, whereas in Sri Lanka, 55% are outsiders. Whether differences between the two areas can be explained by analyzing regional conditions, which might have resulted in different aquaculture practices, is discussed. In Sri Lanka, semi-intensive shrimp monoculture is currently the most common practice, whereas in the Philippines, extensive shrimp/fish polyculture is more common. Previous studies, as well as fieldwork, indicate that extensive culture practices reduce environmental impacts and benefit local people more. Sustainability in aquaculture is, however, also dependent on the extent of mangrove conversion into ponds. As such, extensive and locally owned farms do not necessarily result in an all but sustainable situation. Keeping this in mind, it is discussed if extensive polyculture practices might result in a more sustainable aquaculture, both environmentally and socioeconomically.  相似文献   
956.
Advocates of community-based approaches to environmental management argue that by respecting local circumstances, skills, and concerns we may improve the prospects of achieving environmental sustainability; yet, within nation states such as Canada, environmental conditions, management and enforcement costs and capabilities, and power differentials within and among civic and public sectors may result in a highly differentiated capacity for environmental management across different localities and regions. This article draws on insights of political ecology to 1) create a conceptual framework that identifies key elements shaping regional environmental management regimes and to 2) undertake a comparative analysis to assess how elements interact to generate uneven management outcomes. I compare experiences of two Canadian biosphere reserves designated in 2000: Clayoquot Sound, BC; and Redberry Lake, SK. Analysis reveals that differences in governance and institutional capacities in the biosphere reserves are key to explaining uneven local outcomes. Where the public and civic sectors are strong, a robust and publicly vetted form of management will emerge. Where these sectors are weak and land is held as private property, environmental nongovernmental organizations can set the type and level of management, to the exclusion of effective civic and state involvement. This result may improve environmental sustainability but hinder social sustainability of a management regime and raises questions about the efficacy of community-based management.  相似文献   
957.
Environmental dredging is a primary remedial option for removal of the contaminated material from aquatic environment. Of primary concern in environmental dredging is the effectiveness of the intended sediment removal. A 5-year field monitoring study was conducted to assess the effectiveness of the environmental dredging in South Lake, China. The concentrations of total nitrogen (TN), total phosphors, and heavy metals (Zn, Pb, Cd, Cu, Cr, Ni, Hg, and As) before and after dredging in sediment were determined and compared. Multiple ecological risk indices were employed to assess the contamination of heavy metals before and after dredging. Our results showed that the total phosphorus levels reduced 42% after dredging. Similar changes for Hg, Zn, As Pb, Cd, Cu, Cr, and Ni were observed, with reduction percentages of 97.0, 93.1, 82.6, 63.9, 52.7, 50.1, 32.0, and 23.6, respectively, and the quality of sediment improved based on the criterion of Sediment Quality Guidelines by USEPA and contamination degree values (Cd) decreased significantly (paired t-test, p < 0.05). Unexpectedly, the TN increased 49% after dredging compared to before dredging. Findings from the study demonstrated that the environmental dredging was an effective mechanism for removal of total phosphorus and heavy metals from South Lake. Nevertheless, the dredging was ineffective to remove total nitrogen from sediment. We conclude that the reason for the observed increase in TN after dredging was likely ammonia release from the sediment impairing the dredging effectiveness.  相似文献   
958.
Although the importance of understanding stakeholder beliefs regarding environmental policy has been noted by many authors, research focusing on the heterogeneity of stakeholder views is still very scarce and concentrated on a product-oriented definition of stakeholders. The aim of the present study is to address this gap by examining environmental policy beliefs of stakeholder groups engaged in protected area management. Questionnaires containing 73 five-point Likert scale items were administered to eight different stakeholder groups involved in the management of Greek protected areas. Items referred to core beliefs on environmental policy, namely, the value framework and sustainable development, and secondary beliefs, that is, beliefs on social consensus and ecotourism development. Our study used as a starting point respondent recruitment on the basis of a traditional product-centered approach. We investigated whether environmental policy beliefs can be used to effectively segregate stakeholders in well-defined segments, which override the product-oriented definition of stakeholders. Indeed, K-means clustering revealed an innovation-introduction and an implementation-charged sample segment. The instrument utilized in this research proved quite reliable and valid in measuring stakeholder environmental policy beliefs. Furthermore, the methodology implied that stakeholder groups differ in a significant number of belief-system elements. On the other hand, stakeholder groups were effectively distinguished on a small set of both core and secondary beliefs. Therefore, the instrument used can be an effective tool for determining and monitoring environmental policy beliefs of stakeholders in protected area management. This is of considerable importance in the Greek case, given the recent establishment of 27 administrative bodies of protected areas, all of which are required to incorporate public consultation into management practices.  相似文献   
959.
Increasingly, performance measurement is being used to hold federal agencies accountable, represent environmental progress, and evaluate the effectiveness of environmental programs. The need to track measurable outputs has created a tendency to present programmatic progress solely by quantifiable data, despite the inherent complexity of natural resource management. Wetlands and fire management programs are two specific environmental arenas that have come to overemphasize the tracking of acreage numbers to validate existing policy direction. In both of these arenas, we find the definition and categorization of "countable" acres to be inconsistent and unreliable. We explore this systemic flaw for both wetlands and fire programs and describe its implications for environmental policy and natural resource management more broadly. We conclude with recommendations for improved performance measurement in these arenas.  相似文献   
960.
中型城市发展循环经济研究初探   总被引:2,自引:0,他引:2  
以山东沿海城市日照为例,从转变发展思路、实践科学发展观,破解发展瓶颈、促进经济社会可持续发展,保持资源环境优势、增强区域持续竞争力三个方面分析了日照市发展循环经济的必要性和重要性。提出抓好“小循环”,构筑循环经济微观基础;搞好“中循环”,构筑循环经济示范基地;推进“大循环”,努力建设循环型社会是在当前中小城市经济欠发达、面临环境保护和发展经济双重压力下,实现经济社会又快又好发展的一条好路。  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