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71.
Forest Health Monitoring in the United States: First Four Years   总被引:24,自引:0,他引:24  
To address the need for more effective methods for evaluating and assessing forest ecosystem health, the USDA-Forest Service and the US Environmental Protection Agency through its Environmental Monitoring and Assessment Program developed the Forest Health Monitoring program. The program was initiated in 1990 and by 1994 was present in the major areas of the United States. This paper presents an overview of the program, the indicators and methods developed for the program, and some of the results after four years of monitoring and research.  相似文献   
72.
The 26 December 2004 tsunamis around the Indian Ocean exposed the vulnerability of many coastal communities, including those serving tourists. To draw conclusions regarding disaster risk reduction for tourism in coastal areas, this study surveyed international tourists who survived the tsunami regarding their perceptions and experiences of the disaster. Semi-structured interviews were completed between January and June 2005 of 55 primary interviewees who were international tourists in locations affected by the tsunami. The qualitative data from the interviews yielded commonalities across four main themes with relevance to disaster risk reduction: information and awareness, warning systems, personal preparation, and livelihoods. Three areas are suggested as topics to highlight for further investigation: the connections between sustainable tourism and disaster vulnerability, the role of tourists in disasters, and disaster risk reduction education.  相似文献   
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Recent federal policy proposals to reduce emissions of sulfur dioxide (SO(2)), nitrogen oxides (NO(x)), and mercury from the US electricity sector promise important improvements in air quality and reductions in acid deposition. The cost of achieving these reductions depends on the form and stringency of the regulation. In this research, we analyze the economic benefits and costs of the US Environmental Protection Agency's (EPA's) Clean Air Interstate Rule (CAIR) as characterized in the supplemental rule proposed in June 2004, and the Clean Air Mercury Rule (CAMR) as proposed in February 2004. The assessment integrates a model of the electricity sector, two models of atmospheric transport of air pollutants, and a model of environmental and public health endpoints affected by pollution. We model explicitly the emissions of SO(2), NO(x), mercury and carbon dioxide (CO(2)) and the effects of changes in emissions of SO(2) and NO(x) on environmental and public health. The manner in which mercury emissions are regulated will have important implications not only for the cost of the regulation, but also for emission levels for SO(2) and NO(x) and where those emissions are located. We find the economic benefits of CAIR and CAMR are far greater than the costs. Recent estimates of benefits of reductions in mercury and acidification indicate that our model captures the lion's share of quantifiable benefits. We also find that the EPA would have been justified on economic grounds in pursuing additional SO(2) emissions reductions beyond the requirements of CAIR.  相似文献   
75.
Diluted exhaust from selected military aircraft ground-support equipment (AGE) was analyzed for particulate mass, elemental carbon (EC) and organic carbon (OC), SO4(2-), and size distributions. The experiments occurred at idle and load conditions and utilized a chassis dynamometer. The selected AGE vehicles operated on gasoline, diesel, and JP-8. These military vehicles exhibited concentrations, size distributions, and emission factors in the same range as those reported for nonmilitary vehicles. The diesel and JP-8 emission rates for PM ranged from 0.092 to 1.1 g/kg fuel. The EC contributed less and the OC contributed more to the particulate mass than reported in recent studies of vehicle emissions. Overall, the particle size distribution varied significantly with engine condition, with the number of accumulation mode particles and the count median diameter (CMD) increasing as engine load increased. The SO4(2-) analyses showed that the distribution of SO4(2-) mass mirrored the distribution of particle mass.  相似文献   
76.
Transfers of treated water among inter-connected utilities is becoming more common as the cost of developing new supplies grows, and transfer agreements require well developed rules describing when and how much water will be transferred. The nature of the decision rules governing an agreement must also be coordinated with respect to the treatment and conveyance capacity required to execute the transfers. This study explores different combinations of infrastructure and agreement type that define three different transfer programs, describing the frequency and volume of transfers associated with each, as well as their costs. The agreements are described in terms of the type of decision rule employed: Take-or-Pay, where the timing and quantity of transfers is fixed; Days of Supply Remaining (DSR), which uses a static hydrologic indicator to trigger transfers; and Risk-of-Failure, a probability-based decision rule that involves consideration of both supply and demand. This analysis is conducted within the context of the Research Triangle area of North Carolina (USA), a rapidly growing area that is beginning to approach the practical limits of water resource development. The Risk-of-Failure agreement is shown to reduce the average volume of transfers by over 80% compared to a Take-or-Pay agreement and by roughly half relative to the DSR agreement, leading to significant cost reductions. A utility's willingness to accept something less than guaranteed access to a specified quantity of water (i.e. an interruption) also has a significant impact on cost. Interruptions do not necessarily lead to lower reliability, but rather to the purchasing utility acquiring more water during off-peak periods when the seller has excess treatment capacity available. The lowest cost guaranteed agreement is 40–50% more expensive than the lowest cost interruptible contract.  相似文献   
77.
Several physical and chemical factors limit the production of biofuels, such as the complex process required for the conversion of plant biomass into ethanol. For example, fossil energy inputs needed for the production of ethanol from corn is 1.59 liters per liter of ethanol. One of the many factors limiting energy output from biomass is the extremely low fraction of sunlight reaching a hectare that is captured by the plants. On average only about 0.1% of the sunlight is captured by green plants per year.  相似文献   
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79.
Occupational Health and Safety in Spain has improved considerably over the last decade, most likely due to a new concept where an overall concept of safety culture is defined. Important changes in industrial safety, hygiene, and psychosocial factors present an optimistic panorama for the future of Spain. Despite this general improvement, according to the European Convergence Program, Spanish statistics still offer far from good safety results. In fact, according to 1997 official statistics, Spain had the highest incidence rate for nonfatal occupational accidents of all European Union (EU) countries, and occupied third place for fatal accidents. This paper summarizes the organizational structure of the Spanish National System of Health & Safety at Work, its effective health and safety laws, and statistics on the Spanish work environment obtained from III Spanish National Survey on Work Conditions (1997). The researchers hope that the findings of this work will have an impact on Spanish industry that will subsequently bring about improvements in work conditions and develop assessment and intervention models in occupational health and safety, from a theoretical position integrating environmental, human, and organizational factors.  相似文献   
80.
In agricultural plant production nitrification inhibitors like 3,4-dimethylpyrazole phosphate (DMPP) are used to retard the microbial nitrification process of fertilized ammonium to enhance the nitrogen supply for cultivated crops and to reduce nitrogen losses from the production system. Besides the well-known ammonia-oxidizing bacteria (AOB) it is known for a few years that also ammonia-oxidizing archaea (AOA) are able to perform the first step in nitrification, hence being also a target for a nitrification inhibitor. However, so far no information are available concerning the effectiveness of DMPP and its extent towards AOB and AOA, neither in bulk soil nor in the root-rhizosphere complex. We investigated in a field experiment performed according to agricultural practice the effect of DMPP on the abundance of AOB and AOA two, four and eight weeks after fertilization. We observed impaired abundances of AOB but not of AOA in both soil compartments that were still visible eight weeks after application, possibly indicating a reduced effectiveness of the nitrification inhibitor in our study.  相似文献   
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