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41.
This paper presents the use of a model to predict sustained casing pressure (SCP), from early pressure buildup data, as a basis for inherently safer well integrity testing. Inherently safer principles aim to eliminate or reduce the hazards by design rather than by using protective features. SCP, a well integrity issue exhibited in many wells, is any measurable pressure that rebuilds after being bled down and attributable to causes other than artificially applied pressure or temperature fluctuations in the well. Intrusion of gas, resulting in SCP, can occur because of poor cement bond in the casing or cement deterioration. Gas entering the annulus migrates to the wellhead and represents a hazard due to increased wellhead pressure and the gas inventory. Compromised well integrity can have catastrophic consequences on both environmental and safety aspects.Most regulations require the monitoring, testing and, eventually, the elimination of SCP. However, test data analysis is predominantly qualitative and limited to arbitrary criteria. Due to the high percentage of wells that present SCP, accurate, safe and preferably fast testing methods are needed. This paper implements an analytical model, rooted in the transport processes and thermodynamics of the system, to predict pressure profiles and gas accumulation during SCP testing from early-time pressure buildup data. The amount of gas accumulated during different testing criteria, being 1) current practices and 2) early diagnostic by the analytical model, is calculated and compared. Results show that using the analytical model as a predictive tool, testing time is reduced significantly, thereby limiting the amount of gas accumulated and reducing the risk. This makes the testing procedure inherently safer as well as less time consuming.  相似文献   
42.
本文从立法目的和调整重点、管理体制、调控机制、防治战略、管理措施和实验保障等方面对中美两国的大气污染防治进行了初步比较,并对完善中国的大气污染防治法提出了一些建议。  相似文献   
43.
This map (see the inside back cover of this issue) illustrates the regional patterns of mean annual alkalinity of surface water in the northern portions of Minnesota, Wisconsin, and Michigan, USA. It provides a qualitative graphic overview of the relative potential sensitivity of surface waters to acidic input in the upper midwest portions of the United States. The map is based on data from approximately 14,000 lakes and streams and the apparent spatial associations between these data and macroscale watershed characteristics that are thought to affect alkalinity.For the map of the Upper Midwest Region of the United States, see the inside back cover of this issue.  相似文献   
44.
The challenge of pursuing sustainability in agriculture is often viewed as mainly or wholly technical in nature, requiring the reform of farming methods and the development and adoption of alternative technologies. Likewise, the purpose of sustainability is frequently cast in utilitarian terms, as a means of protecting a valuable resource (i.e., soil) and of satisfying market demands for healthy, tasty food. Paul B. Thompson has argued that the embrace of these views by many in the consumer/environmental movement enables easy co-optation by agribusiness. It also reflects a critical weakness in this movement: a lack of commitment to philosophical principles that depart from the utilitarian premises of the industrial model of agriculture. This paper draws on the writings of Thomas Berry and Liberty Hyde Bailey to identify the philosophical principles of what we call planetary agrarianism. From the perspective of planetary agrarianism, the pursuit of sustainability is a broad and challenging moral, educational, and political task. Berry helps us see that it is fundamentally a project of worldview transition, which requires a new cultural narrative that must rival, in form and appeal, the mythic power of the utilitarian industrial vision. Liberty Hyde Bailey, author of The Holy Earth (1915) and a leader in the land-grant education and nature-study movements, took up the project of worldview transition in his life work. While in some ways dated and flawed, Bailey’s writings are a valuable source of guidance for developing and pursuing a viable philosophy of agriculture for the 21st century.  相似文献   
45.
US/O_3/TiO_2/UV氧化处理苯胺废水实验研究   总被引:2,自引:0,他引:2  
实验采用US/O3/TiO2/UV氧化技术处理模拟苯胺废水,考察了各种技术组合对苯胺废水的处理效果以及技术组合的影响因素。结果表明,US单独使用对苯胺废水的处理效果较差,需要与其它技术联用;纳米TiO2/UV对苯胺废水的降解速度较慢,停留时间需保证纳米TiO2与废水污染物的充分接触,并且需要对纳米TiO2膜及技术参数进行优化以保证光催化的效果;技术组合中有O3时,COD的去除率有很大的提高;比较而言,US/O3/TiO2/UV技术组合对苯胺废水的处理效果最好。采用US/O3/TiO2/UV技术处理苯胺废水时,苯胺废水浓度的增加会导致COD去除率下降;废水pH值的增加会导致COD去除率轻微下降;随反应的进行,废水pH值会向4~6的区间靠拢;臭氧浓度要适中,过大或过小均会导致处理效率的下降;在优化条件下,该技术组合处理苯胺废水20min时的COD去除率达85%以上,60min时则达到96%。  相似文献   
46.
与环保相关的人大建议政协提案能够表达公众的环保诉求,推动地方环保立法、指导环境保护工作。是公众参与环保、监督环保的重要途径。论文以大连市办理建议提案经验为例,对如何发挥人大建议政协提案在环境保护工作中起到的作用进行了阐述。  相似文献   
47.
Introduction: Injuries at work may negatively influence mental health due to lost or reduced working hours and financial burden of treatment. Our objective was to investigate, in U.S. workers (a) the prevalence of serious psychological distress (SPD) by injury status (occupational, non-occupational, and no injury) and injury characteristics, and (b) the association between injury status and SPD. Methods: Self-reported injuries within the previous three months were collected annually for 225,331 U.S. workers in the National Health Interview Survey (2004–2016). Psychological distress during the past 30 days was assessed using the Kessler 6 (K6) questions with Likert-type scale (0–4, total score range: 0–24). SPD was defined as K6 ≥ 13. Prevalence ratios (PR) from fitted logistic regression models were used to assess relationships between injury and SPD after controlling for covariates. Results: The prevalence of SPD was 4.74%, 3.58%, and 1.56% in workers reporting occupational injury (OI), non-occupational injury (NOI), and no injury, respectively. Workers with head and neck injury had the highest prevalence of SPD (Prevalence: OI = 7.71%, NOI = 6.17%), followed by workers with scrape/bruise/burn/bite (6.32% for those with OI). Workers reporting OI were two times more likely to have SPD compared to those without injury (PR = 2.19, 95%CI: 1.62–2.96). However, there was no significant difference in SPD between workers with OI and workers with NOI (PR = 0.98, 95%CI: 0.65–1.48). Conclusion: The prevalence of SPD varied by injury status with the highest being among workers reporting OI. We found that the workers reporting OI were significantly more likely to have SPD than those without injury, but not more than those with NOI. Practical Applications: Mental health management programs by employers are necessary for workers who are injured in the workplace.  相似文献   
48.
Hydraulic fracturing, or fracking, is a controversial but popular method of extracting oil and gas in North America. There are a myriad of completing claims about the economic benefits and the environmental costs of the technology. This paper examines news media coverage of fracking in four Canadian and four American newspapers over a five-year period. A comparison is made at the national level as well as at a paired subnational level between jurisdictions where fracking is embraced and where fracking is banned. The paper demonstrates that in both countries the main storyline is about water quality, but beyond that differences emerge as Americans focus more on wildlife and public health and Canadians focus more on moratoriums and energy independence. Moreover, while there were similarities in media coverage of fracking in pro-fracking and anti-fracking jurisdictions, there were notable differences in attention to the topics of public health and economic benefits.  相似文献   
49.
The present study provides an evaluation of noise pollution in six Urban Parks located in the city of Curitiba, Brazil. Equivalent noise levels (L eq) were measured in 303 points (each point measured during 3 min) spread throughout the Parks. Measured values were confronted with local legislation (Law 10625) allowed limits, and the Parks were thus classified as “acoustically polluted or unpolluted”. Measured values were also evaluated according to international legislation: Decree no. 12 of the City Council of Rome, DIN 18005 for German cities, the World Health Organization, and the United States Environmental Protection Agency. Urban parks in the downtown area of Curitiba, surrounded by roads of heavy traffic and in the midst of intense commercial activities, do not satisfy any of the standards used. The most noise-polluted parks in Curitiba were the Public Walk Park and the Botanical Garden Park, with measured L eq of 64.8 dB(A) and 67 dB(A).  相似文献   
50.
This review focuses on the occurrence and treatment of arsenic (As) in the arid region of northern Mexico (states of Chihuahua and Coahuila) and bordering states of the southwestern US (New Mexico, Arizona, and Texas), an area known for having high As concentrations. Information assembled and assessed includes the content and probable source of As in water, soil, and sediments and treatment methods that have been applied in the area. High As concentrations were found mainly in groundwater, their source being mostly from natural origin related to volcanic processes with significant anthropogenic contributions near mining and smelting of ores containing arsenic. The affinity of As for solid phases in alkaline conditions common to arid areas precludes it from being present in surface waters, accumulating instead in sediments and shifting its threat to its potential remobilization in reservoir sediments and irrigation waterways. Factors such as oxidation and pH that affect the mobility of As in the subsurface environment are mentioned. Independent of socio-demographic variables, nutritional status, and levels of blood lead, cognitive development in children is being affected when exposed to As. Treatments known to effectively reduce As content to safe drinking water levels as well as those that are capable of reducing As content in soils are discussed. Besides conventional methods, emergent technologies, such as phytoremediation, offer a viable solution to As contamination in drinking water.  相似文献   
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