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441.
Truck-based collection of municipal solid waste imposes significant negative externalities on cities and constrains the efficiency of separate collection of recyclables and organics and of unit-price-based waste-reduction systems. In recent decades, hundreds of municipal-scale pneumatic collection systems have been installed in Europe and Asia. Relatively few prior studies have compared the economic or environmental impacts of these systems to those of truck collection. A critical factor to consider when making this comparison is the extent to which the findings reflect the specific geographic, demographic, and operational characteristics of the systems considered. This paper is based on three case studies that consider the specific characteristics of three locations, comparing pneumatic systems with conventional collection on the basis of actual waste tonnages, composition, sources, collection routes, truck trips, and facility locations. In one case, alternative upgrades to an existing pneumatic system are compared to a potential truck-collection operation. In the other cases, existing truck operations are compared to proposed pneumatic systems which, to reduce capital costs, would be installed without new trenching or tunneling through the use of existing linear infrastructure. For the two proposed retrofit pneumatic systems, up to 48,000 truck kilometers travelled would be avoided and energy use would be reduced by up to 60% at an incremental cost of up to $400,000 USD per year over the total operating-plus-capital cost of conventional collection. In the location where a greenfield pneumatic system is already in operation, truck collection would be both less expensive and more energy-efficient than pneumatic collection. The results demonstrate that local geographic, demographic, and operational conditions play a decisive role in determining whether pneumatic collection will reduce energy requirements, produce more or fewer greenhouse gas emissions, and cost more or less over the long-term. These findings point to the local factors that will determine the relative economic and environmental costs and benefits in specific situations.  相似文献   
442.
Diagnosing the processes that threaten species persistence is critical for recovery planning and risk forecasting. Dominant threats are typically inferred by experts on the basis of a patchwork of informal methods. Transparent, quantitative diagnostic tools would contribute much‐needed consistency, objectivity, and rigor to the process of diagnosing anthropogenic threats. Long‐term census records, available for an increasingly large and diverse set of taxa, may exhibit characteristic signatures of specific threatening processes and thereby provide information for threat diagnosis. We developed a flexible Bayesian framework for diagnosing threats on the basis of long‐term census records and diverse ancillary sources of information. We tested this framework with simulated data from artificial populations subjected to varying degrees of exploitation and habitat loss and several real‐world abundance time series for which threatening processes are relatively well understood: bluefin tuna (Thunnus maccoyii) and Atlantic cod (Gadus morhua) (exploitation) and Red Grouse (Lagopus lagopus scotica) and Eurasian Skylark (Alauda arvensis) (habitat loss). Our method correctly identified the process driving population decline for over 90% of time series simulated under moderate to severe threat scenarios. Successful identification of threats approached 100% for severe exploitation and habitat loss scenarios. Our method identified threats less successfully when threatening processes were weak and when populations were simultaneously affected by multiple threats. Our method selected the presumed true threat model for all real‐world case studies, although results were somewhat ambiguous in the case of the Eurasian Skylark. In the latter case, incorporation of an ancillary source of information (records of land‐use change) increased the weight assigned to the presumed true model from 70% to 92%, illustrating the value of the proposed framework in bringing diverse sources of information into a common rigorous framework. Ultimately, our framework may greatly assist conservation organizations in documenting threatening processes and planning species recovery. Inferencia la Naturaleza de las Amenazas Antropogénicas para los Registros de Abundancia a Largo Plazo  相似文献   
443.
我国自来水行业长期以来实行国家经营,由于缺乏竞争以及行业监管不足,致使供水不足、行业经营效率低下、成本较高,因此,采取市场化模式势在必行.对此,我国自来水行业从1992年开始实施以打破垄断、提高效率与改善服务质量为目标的市场化改革,并取得了一定的成效,但是还是存在许多不足.在介绍了我国自来水产业市场化模式的发展历程,并运用经济学的相关理论和实证方法,来分析中国自来水市场化模式.  相似文献   
444.
This paper aims to contribute to the debate on the feasibility of the provision of micro flood insurance as an effective tool for spreading disaster risks in developing countries and examines the role of the institutional-organisational framework in assisting the design and implementation of such a micro flood insurance market. In Bangladesh, a private insurance market for property damage and livelihood risk due to natural disasters does not exist. Private insurance companies are reluctant to embark on an evidently unprofitable venture. Testing two different institutional-organisational models, this research reveals that the administration costs of micro-insurance play an important part in determining the long-term viability of micro flood insurance schemes. A government-facilitated process to overcome the differences observed in this study between the nonprofit micro-credit providers and profit-oriented private insurance companies is needed, building on the particular competence each party brings to the development of a viable micro flood insurance market through a public-private partnership.  相似文献   
445.
This study evaluated the prospective damage costs of PM(2.5) inhalation. We performed a health risk assessment based on an exposure-response function to estimate the annual population risk in the Seoul metropolitan city, Korea. Also, we estimated a willingness-to-pay (WTP) amount for reducing the mortality rate in order to evaluate a statistical life value. We combined the annual population risk and the value-of-statistical-life to calculate the damage cost estimate. In the health risk assessment, we applied the PM(2.5) relative risk to evaluate the annual population risk. We targeted an exposure population of 5,401,369 persons who were over the age of 30. Using a Monte-Carlo simulation for uncertainty analysis, we estimated that the population risk of PM(2.5) inhalation during a year in Seoul is 2181 premature deaths for acute exposure and 18,510 premature deaths for chronic exposure. The monthly average WTP for 5/1000 mortality reduction over ten years is $20.20 USD (95% C.I: $16.60-24.50) and the implied value-of-statistical-life (VSL) is $485,000 USD (95% C.I: $398,000-588,000). The damage cost estimate due to risk from PM(2.5) inhalation in Seoul is about $1057 million USD per year for acute exposure, and $8972 million USD per year for chronic exposure. It is important to note that this cost estimate does not reflect all health damage cost estimates in this urban area. This recommendation is a model for evaluating a mortality risk reduction and as such we must re-evaluate an integrated application of morbidity risk.  相似文献   
446.
High energy prices and the growing concern for “Peak Oil” have put energy analysis, once again, on the front burner. However, before speculating about possible roadmaps regarding our energy future, it would be wise to develop better quantitative analyses. This paper flags the existence of systemic epistemological flaws in the current use of aggregate energy indicators and presents an alternative approach capable of dealing with the issue of multiple dimensions and multiple scales. Starting from a critical appraisal of the aggregate indicator “Economic Energy Intensity” it shows that economic and biophysical variables are often correlated and that their value is determined by characteristics which can only observed across different levels and scales. Complex metabolic systems (systems that use energy to maintain and reproduce themselves) are operating simultaneously at different scales. This implies that changes in the characteristics of parts, defined at the local scale, and changes in the characteristics of the whole, defined at the large scale can only be obtained after establishing a scaling mechanism in the analysis. In order to deal with the issue of scale in energy accounting, we propose to make a distinction between three different categories: (i) primary energy sources (PES) - establishing a link between energy quantities and the associated requirement of biophysical gradients, at the large scale, on the interface black-box/context; (ii) energy carriers (EC) - defining the set of energy inputs required by technical devices for expressing useful functions, at the local scale, within the parts operating inside the black-box; (iii) end uses (EU) the set of functions to be expressed by society across hierarchical levels for reproducing itself. Finally, the paper presents examples of quantitative results obtained using an innovative method of analysis - Multi-Scale Integrated Analysis of Societal and Ecosystem Metabolism (MuSIASEM). We conclude that by using this new accounting method it is possible to generate a better understanding of external and internal constraints determining the desirability and viability of the metabolic pattern of societies.  相似文献   
447.
通过研究系统耦合协同评价体系,构建一个适宜大区域的评价生态文明建设和城市化情况的指标体系,借助该指标体系,从时空两个维度分析黄河经济带2008—2016年生态文明建设和城市化耦合协调发展状况、格局及空间关系。实证结果表明:(1)2008—2016年,黄河经济带生态文明建设成效并不显著,压力依然很大;城市化有所提升,但发展速度依然偏慢。两方面均不存在明显的龙头城市,且空间差异明显。(2)2008—2016年,研究区生态文明建设与城市化处于低度耦合阶段,协调度处于轻度失调状态,生态文明建设普遍滞后于城市化,表现出明显的空间异质性和行政指向性。(3)协调度表现出一定的空间依赖,存在一定的空间溢出效应,地理临近的区域更容易受高协调度区域的影响。  相似文献   
448.
广西北部湾沿海经济区水稻及根系土硒含量特征   总被引:1,自引:0,他引:1  
应用原子荧光光度法对广西北部湾沿海经济区水稻和根系土中的硒含量进行了测试。研究了水稻中硒含量与根系土中硒含量以及土壤性质之间关系。结果表明:研究区水稻中硒含量在0.021~0.335mg/kg之间,平均值为0.074mg/kg,标准差0.045,样品数为70件;根系土中硒含量变化范围为0.167~1.328mg/kg,平均值为0.620mg/kg,标准差0.230,样品数为70件。高于世界土壤表层平均值和全国表层土壤平均值,相关分析结果表明,根系土中S、有机质、P、C、N不利于水稻对硒的吸收,高CaO含量和pH有利于硒的吸收。土壤全硒量不是控制水稻硒水平的最主要因素。  相似文献   
449.
China has put great efforts into air pollution control over the past years and recently committed to its most ambitious climate target. Cost and benefit analysis has been widely used to evaluate the control policies in terms of past performance, future reduction potential,and direct and indirect impacts. To understand the cost and benefit analysis for air pollution control in China, we conducted a bibliometric review of more than 100 studies published over the past two decades, including the cur...  相似文献   
450.
生态资本利用的空间关系影响区域可持续发展。以北部湾经济区2006—2019年面板数据为例,构建空间杜宾模型研究环境规制、经济高质量发展与生态资本利用的空间关系,结论如下:(1)环境规制、经济高质量发展和生态资本构成三E系统。(2)生态资本利用存在显著空间正自相关关系。(3)生态资本供需、流量利用及存量占用与环境规制显著空间正相关,环境规制抑制了存量占用及资本供需和流量利用水平;与经济高质量发展显著空间正相关,经济高质量发展显著提高了资本供给需求与流量利用,也增大了存量占用。(4)交互效应显著抑制了两者对资本供需与流量利用的影响、抑制了环境规制对存量占用的影响,也促进了经济高质量发展对存量占用的影响。研究结论对区域生态资本管控有实际意义。  相似文献   
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