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81.
Carbon dioxide is increasing in the atmosphere and is of considerable concern in global climate change because of its greenhouse gas warming potential. The rate of increase has accelerated since measurements began at Mauna Loa Observatory in 1958 where carbon dioxide increased from less than 1 part per million per year (ppm yr?1) prior to 1970 to more than 2 ppm yr?1 in recent years. Here we show that the anthropogenic component (atmospheric value reduced by the pre-industrial value of 280 ppm) of atmospheric carbon dioxide has been increasing exponentially with a doubling time of about 30 years since the beginning of the industrial revolution (~1800). Even during the 1970s, when fossil fuel emissions dropped sharply in response to the “oil crisis” of 1973, the anthropogenic atmospheric carbon dioxide level continued increasing exponentially at Mauna Loa Observatory. Since the growth rate (time derivative) of an exponential has the same characteristic lifetime as the function itself, the carbon dioxide growth rate is also doubling at the same rate. This explains the observation that the linear growth rate of carbon dioxide has more than doubled in the past 40 years. The accelerating growth rate is simply the outcome of exponential growth in carbon dioxide with a nearly constant doubling time of about 30 years (about 2%/yr) and appears to have tracked human population since the pre-industrial era.  相似文献   
82.
Starting from a risk conflicts perspective, this article challenges two common assumptions of existing research on climate change in public and media discourses. It argues that the evaluation of these discourses on the extent to which these either accurately reflect a scientific consensus or contribute to achieving social consensus insufficiently takes account of the exclusionary mechanisms it starts from. A conceptual and empirical framework is subsequently put forward which allows one to evaluate mediated discourses in terms of the extent to which democratic debate and citizenship are encouraged. Such analysis can reveal the discursive strategies underlying processes of politicization and depoliticization. This perspective is illustrated by an analysis of a local case study: the “Sing for the Climate” campaign. We conclude by calling for a broad systematic research agenda revealing the extent to which de/politicizing discourses are found to influence public and media discourses.  相似文献   
83.
The efficiency of a biopurification system, developed to treat pesticide contaminated water, is to a large extent determined by the chemical and hydraulic load. Insight into the behaviour of pesticides under different fluxes is necessary. The behaviour of metalaxyl, bentazone, linuron, isoproturon and metamitron was studied under three different fluxes with or without the presence of pesticide-primed soil in column experiments. Due to the time-dependent sorption process, retention of the pesticides with intermediate mobility was significantly influenced by the flux. The higher the flux, the slower pesticides will be sorbed, which resulted in a lower retention. Degradation of the intermediate mobile pesticides was also submissive to variations in flux. An increase in flux, led to a decrease in retention, which in turn decreased the opportunity time for biodegradation. Finally, the presence of pesticide-primed soil was only beneficial for the degradation of metalaxyl.  相似文献   
84.
85.
Regional Environmental Change - Protection of natural or semi-natural ecosystems is an important part of societal strategies for maintaining biodiversity, ecosystem services, and achieving overall...  相似文献   
86.
Since 2006, around 600 rainwater harvesting systems have been constructed for agricultural irrigation in Beijing. The financial and economic implications of using these systems are discussed less. It is important to understand the effectiveness of the investments spent on the rainwater harvesting systems. The paper aims to analyze economic and financial performance of the constructed rainwater harvesting systems in rural areas of Beijing through the method of cost benefit analysis. The economic analysis focuses on determining the contribution of rainwater harvesting systems to the development of society, carried out from the point of view of government. The financial analysis allows comparison of the financial implications of using groundwater with using rainwater for agricultural irrigation from the point of view of individual participant, namely the local farmers. The results show that the rainwater harvesting systems are economically feasible. This means rainwater harvesting have positive effects for society. However, the financial feasibility of rainwater harvesting systems depends on the charge for groundwater and on the size of the rainwater harvesting systems. If groundwater is not charged, the rainwater harvesting systems are not financially feasible. If groundwater is charged at 2 Yuan/m3, only large size systems are financially feasible while small and middle sizes systems are not financially feasible. Under these circumstances, only large systems can run smoothly, while farmers may not use the small and medium-size systems.  相似文献   
87.
Goodman BA  Johnson PT 《Ecology》2011,92(3):542-548
Parasites can cause dramatic changes in the phenotypes of their hosts, sometimes leading to a higher probability of predation and parasite transmission. Because an organism's morphology directly affects its locomotion, even subtle changes in key morphological traits may affect survival and behavior. However, despite the ubiquity of parasites in natural communities, few studies have incorporated parasites into ecomorphological research. Here, we evaluated the effects of parasite-induced changes in host phenotype on the habitat use, thermal biology, and simulated predator-escape ability of Pacific chorus frogs (Pseudacris regilla) in natural environments. Frogs with parasite-induced limb malformations were more likely to use ground microhabitats relative to vertical refugia and selected less-angled perches closer to the ground in comparison with normal frogs. Although both groups had similar levels of infection, malformed frogs used warmer microhabitats, which resulted in higher body temperatures. Likely as a result of their morphological abnormalities, malformed frogs allowed a simulated predator to approach closer before escaping and escaped shorter distances relative to normal frogs. These data indicate that parasite-induced morphological changes can significantly alter host behavior and habitat use, highlighting the importance of incorporating the ubiquitous, albeit cryptic, role of parasites into ecomorphological research.  相似文献   
88.
State of the environment reporting (SoER) is a well-established and widely applied environmental management tool in the South African context. Despite a wealth of knowledge about conducting and preparing SoERs, there is a paucity of research on the effect SoER has had on decision-making at the local government sphere. This study investigated the effect of SoER on decision-making for a sample of municipalities in the Gauteng Province of South Africa. The methodology relied on interviews with key role players, which include the ‘‘environmental function’' as well as ‘‘other functions’' responsible for infrastructure development and planning within the municipalities. The results show that notwithstanding the extensive time and resources spent on SoER, it appears to have had a limited effect on decision-making, especially beyond the environmental function. Recommendations to improve the influence of SoER on decision-making in developing countries include improved clarity on the purpose and home of SoER within municipalities, adequate budget and capacity, and effective cooperative governance both within the municipalities, and with other spheres of government.  相似文献   
89.
The effect of arabica coffee management intensity on composition, structure, and regeneration of moist evergreen Afromontane forests was studied in three traditional coffee-management systems of southwest Ethiopia: semiplantation coffee, semiforest coffee, and forest coffee. Vegetation and environmental data were collected in 84 plots from forests varying in intensity of coffee management. After controlling for environmental variation (altitude, aspect, slope, soil nutrient availability, and soil depth), differences in woody species composition, forest structure, and regeneration potential among management systems were compared using one way analysis of variance. The study showed that intensification of forest coffee cultivation to maximize coffee production negatively affects diversity and structure of Ethiopian moist evergreen Afromontane forests. Intensification of coffee productivity starts with the conversion of forest coffee to semiforest coffee, which has significant negative effects on tree seedling abundance. Further intensification leads to the conversion of semiforest to semiplantation coffee, causing significant diversity losses and the collapse of forest structure (decrease of stem density, basal area, crown closure, crown cover, and dominant tree height). Our study underlines the need for shade certification schemes to include variables other than canopy cover and that the loss of species diversity in intensively managed coffee systems may jeopardize the sustainability of coffee production itself through the decrease of ecosystem resilience and disruption of ecosystem services related to coffee yield, such as pollination and pest control.  相似文献   
90.
The concept of eco-industrial sites or sustainable business sites is a noteworthy newcomer in the family of location types. The origin of this type may be considered as a consequence of two development trends, namely the segmentation of the location market on the one hand (an outcome of changing locational tendencies) and the aim of government policy to integrate economic and environmental objectives on the other. In this paper, both trends are analysed. The central aim is to establish the progress of implementing the newly developed location concept in practice and to identify factors of success and failure. The situation in the Netherlands is used as a frame of reference. After the outline of the background, the concept of sustainable business sites, including its definition, is considered and criticized. Then a tentative inventory is presented of the approximately 60 eco-parks which have developed in the past 10 years in the Netherlands, including the results of a questionnaire survey of these 60 parks. To get a better insight into the factors which determine success or failure, short case-studies of a number of the parks are presented. Finally, a number of conclusions are presented, including a discussion of an alternative view of the concept of eco-industrial sites which applies to the continuity of both firm and environment.  相似文献   
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