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431.
化学放热系统热爆炸临界值的随机性   总被引:4,自引:0,他引:4  
提出了化学放热系统热爆炸临界值的随机性问题,并定义了化学放热系统的热安全度和可靠度.将LambertW函数计算出的化学放热系统临界环境温度和系统实际所处环境温度均看作随机变量,假定化学放热系统临界环境温度服从正态分布,应用应力-强度干涉理论计算化学放热系统的热爆炸概率值.化学放热系统热爆炸概率值的计算使热爆炸理论的研究从确定性理论向随机性理论发展.  相似文献   
432.
中国域际关键自然资本竞争效应的测算与分析   总被引:1,自引:0,他引:1  
熊娜 《生态环境》2011,20(2):298-303
以生产生态足迹核算法为基础,引入关键自然资本概念,计算全国32个地区1949至2007年的3类自然资源的本区域生态足迹,即生产性土地、水资本及能源足迹,核算时将水产品、淡水及水电统一在水足迹项下,并对生产性土地和能源足迹的核算口径作相应调整。在此基础上,继而测算关键自然资本竞争效应,从全局及个案2个角度分析区域发展战略对区域关键自然资本竞争效应的影响。这里关键自然资本竞争效应是对区域自然资本禀赋开采活动的抽象,描述战略期内某区域自然资本开采量调整幅度较同期平均水平的相对情况。全局分析,即比较东、中、西部地区1949至1979年非倾向性区域战略、1980至1997年东部倾向性战略和1998至2007年中、西部倾向性战略期的关键自然资本竞争效应,结果显示:关键自然资本竞争效应的调整方向与区域战略倾斜方向相同,第一次调整为东部倾斜,对应着东部境内关键自然资本竞争效应的上升,第二次调整为中、西部倾斜政策,对应着中、西部境内关键自然资本的上升。南水北调工程作为个案分析,补充论述资源再配置工程对关键自然资本竞争效应的影响,通过比较南水北调东、中线相关区域关键自然资本变动情况发现:水源区自然资本生产力下降;不可持续开采方式的负外部性有从"点"向工程沿线扩展的可能。  相似文献   
433.
预抽煤层瓦斯区域防突效果检验指标临界值研究   总被引:1,自引:0,他引:1  
瓦斯突出危险性预测是防治煤与瓦斯突出的关键环节,瓦斯突出预测指标的临界值是决定区域防突是否达标的重要参数。为了确定寺河矿西井区3号煤层的区域预抽后煤层瓦斯防突效果评价指标体系,以瓦斯突出综合作用假说为基础,通过现场采取原始煤样,并在密封煤样罐内达到吸附平衡,测定残余瓦斯含量和残余瓦斯压力的关系,研究了原煤瓦斯含量与瓦斯压力的关系及原煤中水分的对其影响规律,提出始突瓦斯压力对应的瓦斯含量作为评价指标的临界值为10 m3/t,并通过现场跟踪考察对得出的瓦斯含量临界值的可靠性进行了现场验证,结果表明,10 m3/t作为区域防突效果评价的临界指标是可靠的。  相似文献   
434.
People's Biodiversity Registers: Lessons Learnt   总被引:1,自引:1,他引:0  
People's Biodiversity Registers (PBR) document folk knowledge of status, uses, history, ongoing changes and forces driving changes in biodiversity resources, gainers and losers in these processes and people's perceptions of how these resources should be managed. A number of PBRs have been prepared in different parts of India beginning 1995 through initiatives of NGOs and educational institutions working with local communities and village councils. These attempts have been motivated by a desire to promote decentralised systems of management of natural resources and to create the basis for equitable sharing of benefits of commercial utilisation of folk knowledge of uses of biodiversity. The documents bring together important locality specific information on biodiversity resources and ecological processes affecting them. They lead to recognition of conservation oriented local practices such as protection of sacred groves. They help mobilise local communities to prudently manage local biodiversity resources in ways that would promote social justice. It is however important to recognise that not all folk knowledge may be valid, nor all folk practices wise, and to create systems of careful assessment of the material. There are many encouraging signs globally, as well as within India, such as the coming in force of the Convention on Biological Diversity, forces promoting decentralised democratic systems of governance and institutions of co-management of natural resources which suggest that programmes like PBR will have an important role to play in promoting conservation, sustainable use and equitable sharing of benefits of biodiversity resources in the coming decades.  相似文献   
435.
Under a national Livestock Policy Forum in Ethiopia the impact of livestock vaccination during drought was assessed in order to inform the development of a best‐practice guideline. For each of the different types of vaccine used during drought years there was no significant difference in livestock mortality, for any species, in vaccinated compared with non‐vaccinated herds. The limited impact of vaccination on livestock mortality was attributed to weaknesses in the design and implementation of vaccination programmes, including use of inappropriate vaccines, low vaccination coverage, problems with vaccine dosing, incorrect timing of vaccination and problems with vaccine storage. If these weaknesses could be overcome vaccination could be a useful means to protect livestock assets, with considerable benefit‐cost ratios. Vaccination should be conducted as a standard preventive measure during normal years, and programme design should be informed by participatory epidemiological studies.  相似文献   
436.
MBR的临界膜通量及其影响研究   总被引:1,自引:0,他引:1  
采用通量阶梯式递增法测定了MBR的临界膜通量,研究了膜面气液两相流流速对临界膜通量影响,并考察次临界膜通量下MBR处理垃圾渗滤液的运行特性。试验结果表明,膜面气液两相流流速对临界膜通量影响较大,膜面气液两相流流速由0.9 m/s增至1.8 m/s,临界膜通量由12~14 L/(m2·h)增加至16~18 L/(m2·h),两者呈显著正相关关系,相关系数为0.997。次临界膜通量下运行时,膜污染包括不可逆污染和可逆污染2个阶段:不可逆污染阶段以凝胶层污染为主,占总量的72%,而可逆污染阶段以滤饼层形成的阻力为主,占总阻力的68.5%。  相似文献   
437.
The effectiveness of a decision-support tool created to identify protected-area potential within the Nova Forest Alliance (NFA) of Nova Scotia, Canada is assessed from the perspective of a public participatory geographic information system (PPGIS) approach. The application sought to create an integrated GIS-based decision-support tool for community-focused communication and conservation assessment among NFA partners (including private woodland owners, government agencies, forest companies, and non-government organizations) and potential application within other model forests in Canada. The application illustrated that the GIS-based tool, once set up and populated with the necessary data, was able to generate effective visual alternatives to support decision making within the NFA community and elsewhere. However, from a PPGIS perspective, the application faced challenges that influenced the efficacy of its implementation: (1) limitations arose around data quality, use and sharing policies; (2) although opportunities for participation by the NFA partnership were initiated, these proved insufficient to achieve adequate engagement, buy in and support for the process and outcomes; and (3) the expert-grounded GIS-based tool requires a greater degree of expertise than may currently be present in the community. These challenges limit its ongoing use in the NFA and its potential utility in other model forests. For PPGIS-decision-support applications to be effective in the NFA and elsewhere, it is suggested that the following conditions be met: (1) implementation of geographically based data policies to allow for greater data accessibility, specifically with fewer bureaucratic and private sector barriers; (2) engagement of community partners in the initial project design, goal-setting and subsequent stages, even if this requires extensions to anticipated timelines; and (3) development of effective participatory technical systems that meet the needs of participants without being so complex as to constitute a barrier to their use.  相似文献   
438.
酸沉降临界负荷计算模式的修正   总被引:2,自引:0,他引:2  
姚小红  周中平 《环境化学》1998,17(4):315-319
酸沉降临界负荷是酸沉降水平的函数,不同酸沉降水平下,矿物风化速率有数量级差别,在因此,酸沉降临界负荷的计算应先使用判别方程计算平衡PH值,然后确定采用何种方法计算,在欧洲可以直接采用动态模式计算临界负荷,是因为其酸沉水平能满足判别方程成立,但在中国大多数情况下不成立。  相似文献   
439.
In this paper, I examine corporate environmental communication on hydraulic fracturing, or fracking, and industry efforts to shape public perception of resource extraction and its impacts on the environment. I look at how the oil and gas industry (OGI) frames fracking to ease public fear by downplaying risk and shifting its scale with rhetoric presenting the benefits of this emergent technology. Contrasting and building on ecological modernisation versus risk society ideas, I use OGI print advertising supplemented by corporate social responsibility statements and other online material to critically evaluate framing in light of the practice of corporate greenwashing. Findings reveal OGI efforts to positively portray fracking in the interest of unfettered resource extraction and profits from energy production. Several themes emerge in OGI framing rhetoric, starting with the establishment of trust through education and claims of transparency and continuing with ideas touting safety and responsibility, scientific progress, economic benefits and jobs, energy security, environmental protection, and sustainability. On the whole, such rhetoric reflects ecological modernisation ideas that shift the perception of risk and its consequences, framing fracking in a way that obscures the negative impacts of dependency on a fossil fuel-based economy.  相似文献   
440.
This paper examines the role and effectiveness of local institutions in the management of forest biodiversity in New Dabaga-Ulongambi Forest Reserve,Tanzania.Data were obtained through questionnaires,interviews,focus group discussions,participatory rural appraisal and field observations.The study revealed that the most remarkable local institutions connected to forest biodiversity management include:Village Natural Resources Management Committee(92%),tree nursery group(79.4%),beekeeping groups(61.1%),fish farming(43.3%),livestock rearing group(33.9%).Main activities carried out by local institutions which directly contribute to the sustainability of forest reserve include:forest patrols,fire extinguish,preparation of fire breaks,planting of trees along the forest boundaries,creation of awareness,arresting of forest defaulters,participation in income generation activities.For the purpose of realization that local communities are capable of managing forest biodiversity through their traditional institutions,the policy should provide tangible opportunity for local communities to meet their needs as they manage the forests.  相似文献   
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