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排序方式: 共有235条查询结果,搜索用时 15 毫秒
81.
China is the second largest emitter of greenhouse gases (GHG) in the world, with potentially about two thirds of total Certified Emission Reductions (CERs) for Asia on the world carbon market (). Since 68% of its primary energy is from coal, China's average energy intensity is 7.5 times higher than the EU and 4.3 times higher than the US (EU, 2003). Therefore, introducing advanced clean technologies and management to China represents opportunities for Annex I countries to obtain low-cost CERs through CDM projects, and access to one of the largest potential energy conservation markets in the world. CDM can provide a win-win solution for both China and Annex I countries, and the Chinese government considers that the introduction of CDM projects can bring advanced energy technologies and foreign investment to China, thereby helping China's sustainable economy and generating CERs. As energy efficiency is generally low and carbon intensity is high in both China's energy supply and demand sectors, numerous options exist for cost-effective energy conservation and GHG mitigation with CDM. This paper reviews current Chinese policies and administrative and institutional settings for CDM cooperation, and discusses existing policy, institutional and other barriers in the energy market by drawing on observations and experience from previous initiatives such as Cleaner Production and energy efficiency. Some options to remove these barriers are addressed. In order to make CDM projects feasible, China's government needs to promote awareness, streamline administrative systems, and be more active in building a competitive edge in the world carbon market. 相似文献
82.
Pablo del Río Javier Carrillo-Hermosilla Totti Könnölä Carlos García Suárez 《Mitigation and Adaptation Strategies for Global Change》2008,13(8):863-885
This paper empirically shows how the uncertainty associated to the absence of a mitigation regime which follows the United
Nations Framework Convention on Climate Change Kyoto Protocol (UN FCCC Kyoto Protocol) is affecting investments in abatement
activities in the EU electricity sector and, thus, future emissions levels. Based on a survey of EU electric utilities, it
identifies the most likely post-Kyoto scenarios considered by them and how they are coping with such uncertainty in their
investment decisions. It is found that firms react differently to such uncertainty and adopt different strategies to cope
with it, diversifying their emissions control activities. Although most companies foresee post-Kyoto compliance regimes with
emissions trading systems, they differ in their perceptions of the form that a post-Kyoto regime could take and are, thus,
positioning differently to face such regime. The particular features of each company and the country where they operate affect
their perception of the uncertainties, their position regarding a possible post-Kyoto regime and their inclination to carry
out mitigation activities. Complying with Kyoto (and, eventually, post-Kyoto) targets significantly influences the investment
decisions of European electricity companies. Uncertainty about a post-Kyoto regime may already be affecting investments in
mitigation activities in the electricity sector. Therefore, significant progress has to be made in the definition of a post-Kyoto
regime. It is urgent to define and agree internationally the emissions reduction objectives and the mitigation instruments
that will be accepted for compliance, ensuring continuity of the international emissions trading system foreseen in the Kyoto
Protocol.
相似文献
Pablo del RíoEmail: |
83.
84.
利用"十五"系统对所选取的地震事件进行了重新定位,将震中位置与"九五"系统输出的地震目录进行对比分析,得到两套系统在定位结果方面的一致性。同时,对HYP02000和HYPOSAT两种定位方法的适用性进行了比较。 相似文献
85.
Modeling changes in the coastal ecosystem of the Pearl River Estuary from 1981 to 1998 总被引:2,自引:0,他引:2
The coastal ecosystem of the Pearl River Estuary (PRE) has been overfished and received a high level of combined pollution since the 1980s. Ecopath with Ecosim was used to construct two ecosystem models (for 1981 and 1998) to characterize the food web structure and functioning of the ecosystem. Pedigree work and simple sensitivity analysis were carried out to evaluate the quality of data and the uncertainty of the models. The two models seem reliable with regards to input data of good quality. Comparing the variations of outputs of these two models aimed to facilitate assessment of changes of the ecosystem during the past two decades.The trophic structure of the ecosystem has changed with an increase in the biomass proportion of lower trophic level (TL) organisms and a decrease in top predator biomass proportion. All the indices of ecosystem maturity examined show that the system was in a more mature condition in 1981 than in 1998, although the system has been in a condition of stress due to anthropogenic disturbances, such as environmental pollution and habitat destruction since 1981. The ecosystem was aggregated into six and seven integral TLs in 1981 and 1998, respectively, using the trophic aggregation routine of Ecopath. Most of the total system biomass and catch took place at TL II and III in both years. But the distribution of the total system biomass and catch at different TLs changed with decreasing proportions in higher TLs in 1998. The mean transfer efficiency was 9.1% and 10.2% in 1981 and 1998, respectively.Comparative network analysis allowed quantification of the importance of direct and indirect trophic interactions among functional groups. Moreover, a method derived from the mixed trophic impact (MTI) analysis allowed estimating importance of groups in terms of “keystoneness” and identifying the keystone species in the two models over the past two decades. The results indicate that there were no clear keystone species in 1998 but two keystone species at medium trophic levels were identified in 1981. Moreover, organisms located at low trophic levels such as phytoplankton, zooplankton and benthic invertebrates were identified to have relatively high keystoneness in the ecosystem. 相似文献
86.
Cycling index is an important ecological indicator used in ecosystem analysis. The higher the cycling in an ecosystem, the higher the utilization of mass and energy within the system before it is lost due to respiration and other factors. For a stock-flow type ecosystem model at steady state, Finn’s cycling index (FCI) can be computed using simple matrix algebra. However, it is difficult to measure how well this index represents the actual cycling occurring in the system. In this paper, we study cycling in ecological networks using an individual based approach (particle tracking algorithm). This new simulation method provides access to the pathway data of individual particles that flow in the system, therefore one can quantify cycling using this pathway data quite literally. We used particle tracking simulations (PTS) to compute a cycling index using Finn’s idea of flux based cycling. Our simulation based results (using no matrix algebra) agree with Finn’s cycling index, verifying the accuracy of both the PTS, and the original linear algebraic formulation of FCI. 相似文献
87.
88.
Hongcan Cui Ronghua Xu Zhong Yu Yuanyuan Yao Shaoqing Zhang Fangang Meng 《Frontiers of Environmental Science & Engineering》2023,17(3):36
89.
人工神经网络法在大气污染预报中的应用 总被引:3,自引:0,他引:3
以鞍山市为例,应用人工神经网络方法,模拟人脑的思维方式,建立了大气污染物浓度的神经网络预报模型,并将计算结果与监测值进行了对比验证,计算结果表明,BP模型应用于大气污染物浓度预报具有较高的预报精度。 相似文献
90.
Introduction: Safety performance functions (SPF) are employed to predict crash counts at the different roadway elements. Several SPFs were developed for the various roadway elements based on different classifications such as functional classification and area type. Since a more detailed classification of roadway elements leads to more accurate crash predictions, multiple states have developed new classification systems to classify roads based on a comprehensive classification. In Florida, the new roadway context classification system incorporates geographic, demographic, and road characteristics information. Method: In this study, SPFs were developed in the framework of the FDOT roadway context classification system at three levels of modeling, context classification (CC-SPFs), area type (AT-SPFs), and statewide (SW-SPF) levels. Crash and traffic data from 2015-2019 were obtained. Road characteristics and road environment information have also been gathered along Florida roads for the SPF development. Results: The developed SPFs showed that there are several variables that influence the frequency of crashes, such as annual average daily traffic (AADT), signalized intersections and access point densities, speed limit, and shoulder width. However, there are other variables that did not have an influence in crash occurrence such as concrete surface and the presence of bicycle slots. CC-SPFs had the best performance among others. Moreover, network screening to determine the most problematic road segments has been accomplished. The results of the network screening indicated that the most problematic roads in Florida are the suburban commercial and the urban general roads. Practical Applications: This research provides a solid reference for decision-makers regarding crash prediction and safety improvement along Florida roads. 相似文献