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611.
612.
In marine ecosystems ecological and environmental conditions continuously change, possibly supporting the wide range of phytoplankton species coexisting in aquatic environments. Phytoplankton communities are not homogeneously distributed in the water column due to the spatial and temporal variability of turbulent mixing and the concurrent biological response. In this paper an individual-based model (Lagrangian method) simulating the basic physiology of two coexisting phytoplankton species has been developed. The species, sharing the same availability of light and nutrient resource, are characterized by different photo-physiological parameters. The spatial and temporal evolution of turbulent mixing is simulated introducing vertical profiles of measured eddy diffusivity. Three case studies have been examined to analyze the role of environment–individual interactions in determining bloom conditions for both the selected species. The organisms experience recurrent fluctuations of light, temperature, and nutrient concentration gradients, due to the turbulent mixing in the water column, which have significant effects on the growth of the phytoplankton species. In all the numerical experiments, the temporal and spatial variability of different forcings do not support the prevalence of one species over the other over the time scale typical of a phytoplankton bloom.A well mixed water column favours the growth of both the populations while a variable mixing regime limits their growth reducing the photophysiological differences between the species.  相似文献   
613.
人力资本法评估农业污染地下水环境价值损失   总被引:1,自引:0,他引:1  
应用人力资本法(HCA)评估了华北典型高产粮区地下水资源硝酸盐污染的价值损失.引用国外的研究结果,建立了硝酸盐污染浓度与健康损害的剂量反应关系,分病因预测了地下水污染超标区增加的死亡人口数量.按照潜在寿命损失人年(YPLL)的计算方法,构造了人力资本损失总量估算函数.应用该函数评估了研究区农业面源污染地下水资源的价值损失为860.8万元/a,相当于每公顷耕地面积上增加外部环境成本293.9元/a.  相似文献   
614.
基于能值理论的生态足迹方法改进   总被引:5,自引:0,他引:5  
生态足迹方法自提出以来受到广泛关注,其缺点也受到一些学者的批评。ZhaoSheng等2005年提出能值足迹法,弥补了生态足迹法以土地生产能力为限制的缺点。论文提出区域能值足迹法,以弥补其改进方法不能够反映区域实际情况和技术进步带来影响的不足。最后,以岷江上游1982到2002年为例应用3种方法进行计算分析。结果表明研究区生态足迹呈缓慢上升趋势,生态足迹方法计算结果<能值足迹<区域能值足迹;生态承载力计算结果显示生态足迹与区域能值足迹方法结果呈平缓下降趋势,而能值足迹方法结果呈不规则变动。区域能值足迹法能够考虑到区域实际情况和技术进步,但它不能完全代替生态足迹方法,将其结合应用将得到更多信息。  相似文献   
615.
阿尔金山国家级自然保护区管理机制的探讨   总被引:1,自引:0,他引:1  
自然保护区的建设和管理是环境保护工作的一个重要方面。也是保护自然资源和生物多样性、建设现代文明的需要,因此对保护区管理的指导思想应立足于保护,着眼于开发,以保护带开发,以开发促保护,走保护与开发组结合的路子。为适应当前形势,切实加强阿尔金山自然保护区(国家级)的管理工作及体制的改革,作者从保护区的现状及存在的问题,探讨新形势下保护区的建设工作。为加强阿尔金自然保护区的建设和管理好自然保护区途径进行  相似文献   
616.
India's forest biodiversity management regime is analysed at the policy, legal and institutional levels, from the perspective of the triple objectives of the Convention on Biological Diversity and the principles of the Indian constitution. The forest biodiversity management regime has both structural and functional flaws that render it largely incapable of facing the challenge of increasing biodiversity degradation and deepening poverty among the Adivasis and other forest‐dependent communities. The paper argues for the reform of the forest biodiversity management regime and offers recommendations in regard to most aspects of the regime, with a view of putting the country's conservation enterprise on a course that is effective, sustainable and inclusive, rejecting the report of the High Power Committee (HPC) (also known as the Subramanian Committee), which is premised on easing corporate access to forests.  相似文献   
617.
Initiatives to reduce community carbon emissions and foster sustainable lifestyles have had varying degrees of success. There is now a need for a re-energised, concerted and joined-up approach that places environmental issues in a wider context – one that improves quality of life while building community resilience. This involves enhancing the capacity of neighbourhoods to recover, respond and adapt to environmental and socio-economic changes. This paper examines the experience gained in a participatory action research (PAR) study to build community resilience, where facilitators supported residents to take ownership of their own agendas. The New Earswick Good Life Initiative (GLI) was an 18-month project undertaken in a low-income suburb of York (UK). A range of approaches were used to identify activities which had the most potential to nurture resilience and foster a shift towards greater environmental sustainability. The GLI highlighted how the introduction of new ideas not only need to be locally relevant but also requires care and time in order for them to embed within community. Altering the way a community manages its environment involves transforming social relationships, strengthening institutions and influencing local power balances. Furthermore, it is necessary to build social capital, knowledge, leadership skills and support social networks to allow communities to effectively engage with relevant local and national policies. Only by providing opportunities to develop these resilient attributes can increased local responsibility be successful. The paper concludes by providing guidance on strengthening community resilience and delivering pro-environmental behaviour change.  相似文献   
618.
There is an urgent need globally to trigger fundamental societal changes in water management away from existing unsustainable paradigms. This paper attempts to understand the evolution of newspaper coverage of water issues in China by analyzing water-related articles in a major national newspaper, the People’s Daily, over the period 1946–2012 using a content analysis approach. The major findings include the following: (1) water issues were in relatively prominent positions in the newspaper; (2) the reporting of water issues in China experienced three stages: 1946 to the middle of 1980s—flood and drought control and water for food production, the middle of 1980s to 1997—water for economic development, and 1998 to the present—water for the environmental sustainability and economic development; (3) the reporting of water issues in the People’s Daily clearly reflected China’s top-down water resources management system, and no “real” public opinions on water were reported during the study period; and (4) the People’s Daily is just a wind vane of Chinese mainstream values and policies on water. The findings supported the realist assumption that the societal value changes on water issues in China were triggered by a range of factors including biophysical pressure (floods and droughts), political campaign (the Cultural Revolution), macro-economic reform (Reform and Opening-up), water institutional arrangement (the Water Law), and water management reform (the No. 1 Central Document on water reform). While there are similarities and differences between this study and other studies, important implications for more sustainable water management are a need to strengthen academic specialists’ and NGO’s voices in the newspaper to create a better informed public, and to stimulate practices toward sustainable water use.  相似文献   
619.
The proactive displacement by public authorities of populations from areas perceived to be exposed to a high risk of disaster presents complex human rights challenges. Provided that no ulterior motive is at play, the use of compulsory evacuations and relocations as policy responses to such risk is mandated by the duty to protect the right to life. However, proactive displacement in the interest of saving lives can be problematic as such measures can lead to the limitation of other human rights, resulting in an intricate assessment of whether compulsory evacuation or permanent relocation is proportional in any given circumstance. Such an analysis demands critical attention by public authorities to the perception of the disaster risk in question and problematises claims to objectivity of official risk assessments. Furthermore, it poses the question as to whether measures designed to address the disaster risk in question that are less intrusive than relocation may be available to public authorities.  相似文献   
620.
左银虎 《化工环保》2017,37(3):371-380
利用二苯碳酰二肼显色,Triton X-100-正辛醇浊点萃取,建立了一种分光光度法测定水中Cr(Ⅵ)的新方法,并探讨了不同测定条件对测定效果的影响。优化后的测定条件为(总体积50 mL)1 mol/L稀硫酸加入量1.0mL、2 g/L二苯碳酰二肼溶液加入量1.5 mL、10 g/L Triton X-100溶液加入量1.5 mL、3 g/L苯甲酸溶液加入量4.0mL、正辛醇加入量5.0 mL。Cr(Ⅵ)质量浓度在0~20μg/L范围内符合朗伯-比尔定律,线性回归方程的相关系数为0.995 5。该方法应用于水样中痕量Cr(Ⅵ)的测定,相对标准偏差小于2.5%,加标回收率为95.7%。  相似文献   
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