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641.
642.
基于模糊Petri网的危险品运输安全评估模型及应用 总被引:3,自引:3,他引:0
针对现代危险品运输安全监控问题,以运输费用、事故风险、灾害致灾、补救能力为运输安全评估的关键因素,建立安全分析的评估指标体系,提出一种基于模糊Petri网的危险品运输安全评估模型。首先应用转换规则给出评估指标体系的模糊Petri网表示和在Petri网模型的基础上的模糊推理算法,其次结合层次分析法(AHP),采取定性与定量分析相结合的方法进行安全评价;最后给出基于ArcGIS的评估模型实现方法,并应用于危险品运输安全监控系统的开发。模糊Petri网的数学特性及易于实现的特性,使得安全评估模型的建立,有助于实现运输安全评估策略的形式化、定量化和动态决策,而基于安全评估模型的危险品运输车辆监控系统的成功开发,进一步表明评估模型、推理算法和实现方法是合理可行的。 相似文献
643.
事故树定性分析法在实际运用中存在的问题 总被引:1,自引:0,他引:1
事故树分析法是一种应用广泛的系统安全分析方法,特别是其定性分析法在安全评价、事故调查分析中得到普遍运用。但是这种方法在实际运用中存在一些常见的问题,不易引起人们的重视。该文根据目前事故树分析法在实际运用中存在的一些突出问题,从定性分析,即最小割集和最小径集求取、结构重要度排序、事故树结果分析三个方面进行了探究,这些问题的存在说明了只有深刻的理解系统分析方法的内在涵义才能在实践中得到正确运用。文中在提出问题的同时给出了正确的运用步骤,力求使这种方法的运用更加规范、正确。 相似文献
644.
Is ISO 14001 a gateway to more advanced voluntary action? The case of green supply chain management 总被引:1,自引:0,他引:1
Toshi H. Arimura Nicole Darnall 《Journal of Environmental Economics and Management》2011,61(2):170-182
Using Japanese facility-level data, we estimate the effects of ISO 14001 certification on the promotion of more advanced practices, namely green supply chain management (GSCM). Our results show that ISO 14001 promotes GSCM practices. Facilities with environmental management systems (EMS) certified to ISO 14001 are 40% more likely to assess their suppliers' environmental performance and 50% more likely to require that their suppliers undertake specific environmental practices. Further, government programs that encourage voluntary EMS adoption indirectly promote GSCM practices. These programs increase the probabilities that facilities will assess their suppliers' environmental performance and require suppliers to undertake specific environmental practices by 7% and 8%, respectively. Combined, these findings suggest that there may be significant but previously unnoticed spillover effects of ISO 14001 and government promotion of voluntary action. 相似文献
645.
Quantifying the sustainability of water use systems: Calculating the balance between network efficiency and resilience 总被引:1,自引:0,他引:1
Y. LiZ.F. Yang 《Ecological modelling》2011,222(10):1771-1780
In ecological network theory, network efficiency and resilience are two essential but complementary attributes of the network structure, and a balance between these factors is critical for an ecosystem's long-term sustainability. Our paper introduces this method and related concepts into water use systems to provide a new angle for sustainability quantification. In this paper, we investigate the meanings of network efficiency and resilience in the context of sustainable development of water use systems, and define sustainable systems based on the optimal balance between network efficiency and resilience. With the consideration of complex artificial characteristics of water use, we propose an optimal water use network and quantify its flows. By ascendency calculation, the balanced network structure can be determined. We then use the four sub-basins of China's Haihe River as a case study to illustrate how the optimal network can be constructed and how the optimal balance for each scenario can be calculated. The results show that the optimal balance for the sub-basins has ascendency values ranging from 0.5970 to 0.7161. By analyzing the contribution of each water use activity to network's balance structure, the location of the optimal balance in water use systems can be better understood. This research represents the first attempt to explore the balance between a network structure's efficiency and resilience as a way to quantify the sustainability of water use systems, and builds a foundation for future studies on the assessment, regulation, and management of water resources. 相似文献
646.
Urbanization is a human-dominated process and has greatly impacted biodiversity, ecosystem processes, and regional climate. To understand the socioeconomic drivers of urbanization and project future urban landscape changes, multi-agent systems provide a powerful tool. We develop an agent-based model of urban growth for the Phoenix metropolitan region of the United States, which simulates the behavior of regional authorities, real estate developers, residents, and environmentalists. The BDI (Beliefs-Desires-Intentions) structure is employed to simulate the agents behavior and decision models. The heterogeneity of agents is reflected by adjusting parameters according to the agents’ beliefs, desires and preferences. Three scenarios, baseline, economic development priority and environmental protection, are developed and analyzed. The combination of multi-agent system and spatial regression model is employed to predict the future urban development of the Phoenix metropolitan region. Landscape metrics are used to compare the spatial patterns of the urban landscape resulting from different scenarios in different times. In general, with the rapid urban expansion, the shape of urban patches will become more regular as many of them become coalesced. The spatial analysis of urban development through modeling individual and group decisions and human-environment interactions with a multi-agent systems approach can enhance our understanding of the socioeconomic driving forces and mechanisms of urban development. 相似文献
647.
Angelina Sanderson Bellamy Ella Furness Poppy Nicol Hannah Pitt Alice Taherzadeh 《Ambio》2021,50(4):782
The COVID-19 pandemic has highlighted weaknesses in global food systems, as well as opening windows of opportunity for innovation and transformation. While the nature and extent of this crisis is rare, extreme climatic events will increase in magnitude and frequency, threatening similar societal impacts. It is therefore critical to identify mechanisms for developing food systems that are resilient to such impacts. We examine impacts of the crisis on UK food systems and how these further entrenched social inequalities. We present data on the experiences and actions of producers, consumers, and community organisers. The data were collected by adapting ongoing research to include surveys, interviews and online workshops focused on the pandemic. Actors’ responses to the pandemic foreshadow how enduring change to food systems can be achieved. We identify support required to enable these transformations and argue that it is vital that these opportunities are embedded in food justice principles which promote people-centred approaches to avoid exacerbating injustices prevalent pre-crisis. Learning from these experiences therefore provides insights for how to make food systems elsewhere more resilient and just. 相似文献
648.
Assessments of large-scale changes in habitat are a priority for management and conservation. Traditional approaches use land use and land cover data (LULC) that focus mostly on “structural” properties of landscapes, rather than “functional” properties related to specific ecological processes. Here, we contend that designing functional analyses of LULC can provide important and complementary information to traditional, structural analyses. We substantiate this perspective with an example of functional changes in habitat due to industrial anthropogenic footprints in Alberta’s boreal forest, where there has been little overall forest loss (~ 6% structural change), but high levels of functional change (up to 93% functional change) for species’ habitat, biodiversity, and wildfire ignition. We discuss the methods needed to achieve functional LULC analyses, when they are most appropriate to add to structural assessments, and conclude by providing recommendations for analyses of LULC in a future of increasingly high-resolution, dynamic remote sensing data.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01434-5) contains supplementary material, which is available to authorized users. 相似文献
649.
David W. Neumann Edith A. Zagona Balaji Rajagopalan 《Journal of the American Water Resources Association》2006,42(5):1275-1284
ABSTRACT: Warm summer stream temperatures due to low flows and high air temperatures are a critical water quality problem in many western United States river basins because they impact threatened fish species’habitat. One way to alleviate this problem is for local and federal organizations to purchase water rights to be used to increase flows, hence decrease temperatures. Presented is a Decision Support System (DSS) that can be used in an operations mode to effectively use water acquired to mitigate warm stream temperatures. The DSS uses a statistical model for predicting daily stream temperatures and a rule‐based module to compute reservoir releases. Water releases are calculated to meet fish habitat temperature targets based on the predicted stream temperature and a user specified confidence of the temperature predictions. Strategies that enable effective use of a limited amount of water throughout the season have also been incorporated in the DSS. The utility of the DSS is demonstrated by an example application to the Truckee River near Reno, Nevada, using hypothetical operating policy and 1988 through 1994 inflows. Results indicate that the DSS could substantially reduce the number of target temperature violations (i.e., stream temperatures exceeding the target temperature levels detrimental to fish habitat). 相似文献
650.