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221.
In recent years, the goal of nature preservation has faced, almost worldwide, an increase in the number of visitors who are interested in experiencing protected areas resources, landscapes and stories. Spain is a good example of this process. The rapidly increasing numbers of visitors have prompted administrations and managers to offer and develop a broad network of facilities and programs in order to provide these visitors with information, knowledge and recreation. But, are we doing it the best way? This research focuses on developing and applying a new instrument for evaluating the quality of visitor management in parks. Different areas are analyzed with this instrument (78 semi-quantitative indicators): planning and management capacity (planning, funding, human resources), monitoring, reception, information, interpretation, environmental education, training, participation and volunteer's programs. Thus, we attempt to gain a general impression of the development of the existing management model, detecting strengths and weaknesses. Although Spain's National Parks constituted the specific context within which to develop the evaluation instrument, the design thereof is intended to provide a valid, robust and flexible method for application to any system, network or set of protected areas in other countries. This paper presents the instrument developed, some results obtained following its application to Spanish National parks, along with a discussion on the limits and validity thereof.  相似文献   
222.
In Mexico, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) was used until the year 2000, principally in agriculture and anti-paludal program health campaigns. The southeastern region of Mexico was an important area of malaria, and from 1957 DDT was applied indoors every 6?months, with a coverage of 2?g/m2. The current study was performed in Tabasco, a Mexican state located in the southeastern region of Mexico. DDT and 1,1-dichloro-2,2-bis(4-chlorophenyl)ethene (DDE) were analyzed by gas chromatography/mass spectrometry. In general, low levels were found in household outdoor samples; the levels of DDT ranged from not detectable to 0.048?mg/kg, and of DDE from 0.001 to 0.068?mg/kg. An important finding was that, in all communities where DDT in blood was analyzed, exposure to DDT was found, indicating both past and present exposure. Although the levels found in this study were lower than other studies in Mexico, there is a need to evaluate whether the people living in the study area are at risk.  相似文献   
223.
Visual displays are signals that may be selected to increase visibility. Light is a crucial component in the transmission of visual signals, and white colour is very conspicuous when illuminated by sun and exhibited against darker backgrounds. Here we tested the hypothesis that orientation of sexual displays in male great bustard (Otis tarda) depends upon position of the sun, i.e., males direct their uplifted white tails towards the sun in order to maximise signal detectability to distant females. We recorded the orientation of 405 male displays in relation to the sun and to females at seven leks. Great bustard males signalled towards the sun more often than expected by chance in early morning, although this pattern was not obvious at other times of day, when males displayed more towards females. Our hypothesis was further supported by the fact that displays were more directed towards the sun when the sun was most visible. Males were more likely to direct their displays towards females during the most elaborate components of their courtship display and when there were fewer males on the lek. Pointing white plumage to the sun may be a behaviour selected in species living in steppe-like open landscapes if individuals obtain net fitness benefit by increasing the likelihood of mating.  相似文献   
224.
Dispersal is an important factor that determines the degree of gene flow and, hence, the degree of differentiation among populations. Using two long-term datasets on natal philopatry and short-distance dispersal in barn swallows Hirundo rustica from Denmark and Spain, we evaluated the fitness costs and benefits and test a number of predictions about the functional significance of dispersal. The proportion of philopatric individuals was more than six times larger in Spain than in Denmark, with a higher rate of philopatry in males than in females. Dispersal propensity decreased in both populations during the course of the study. Males from the more philopatric Spanish population lived longer when philopatric rather than dispersing while that was not the case for either sex of the less philopatric Danish population. There were large differences in dispersal propensity among cohorts and breeding sites, suggesting that sites differed in their suitability as sites for immigrants. We found no evidence consistent with the mate competition hypothesis suggesting that males in better condition or with larger condition-dependent secondary sexual characters were more likely to be philopatric. These findings suggest that there is a high degree of intraspecific variation in dispersal propensity between populations, probably relating to local differences in costs and benefits of philopatry and dispersal.  相似文献   
225.
Rewilding is a restoration strategy that aims to return anthropogenic ecosystems to a “self-organized” state, by reinstating trophic complexity through disturbance (e.g. predation, herbivory), dispersal and connectivity. In depopulated areas of Europe, lite versions of rewilding, that maintain but minimize the management of rewilding species (e.g. predators, large herbivores) is gaining support. Livestock rewilding (LR) is a form of rewilding-lite, that uses livestock landraces as keystone species in the restoration of herbivory (the functional integrity of ecosystems) offering ecosystem services, such as ecotourism and the sale of livestock population surpluses, that can mitigate the economic and social effects of rural depopulation. Many challenges remain to implementing LR, including (i) more empirical evidence is required of the feasibility of LR across a variety of habitats and conditions, and (ii) understanding the hurdles that legislation poses for LR, the latter being the aim of this study. To accomplish this, we reviewed the EU legislation on environmental protection, animal health and welfare, identification and traceability, and ownership and civil responsibility, to assess how this might apply to LR. Although there is no specific EU legislation prohibiting LR, the review indicates that it is not clear what legislation applies to LR, as LR’s status lies between that of livestock and wild species. As such the existing legislation can be a serious impediment to the development of LR programmes. We highlight the needs for a legal definition, and status of LR species and their ownership. We propose ways to adapt this legislation to support the application of LR programmes in abandoned areas of EU, for example, by using legal exceptions intended for livestock under extensive animal farming systems.  相似文献   
226.
Polyhydroxybutyrate is a type of biopolymer that can be produced from hydrolyzed polysaccharide materials and could eventually replace polypropylene and polyethylene, being biodegradable, biocompatible and produced from renewable carbon sources. However, polyhydroxybutyrate is not still competitive compared to petrochemical polymers due to their high production costs. The improvement of the production processes requires a search for new alternative raw materials, design of the pretreatment technique and improvement in the fermentation and separation steps. In addition, if the polyhydroxybutyrate production is coupled into a multiproduct biorefinery it could increase the economic and environmental availability of the process through energy and mass integration strategies. In this work alternatives of energy and mass integrations for the production of polyhydroxybutyrate into a biorefinery from residual banana (an agro-industrial waste) were analyzed. The results show that the energetic integration can reduce up to 30.6% the global energy requirements of the process and the mass integration allows a 35% in water savings. Thus, this work demonstrates that energy and mass integration in a biorefinery is a very important way for the optimal use of energy and water resources hence decreasing the production cost and the negative environmental impacts.  相似文献   
227.
228.
Sludge generation is currently one of the most important issues for sewage treatment plants in Chile. In this work, the life cycle environmental impacts of four sludge management scenarios were studied, focusing on the comparison of current practices and advanced anaerobic digestion (AD) using a sequential pre-treatment (PT). The results show that AD scenarios presented lower potential impacts than lime stabilization scenarios in all assessed categories, including climate change, abiotic depletion, acidification, and eutrophication in terrestrial, marine and freshwater ecosystems. The overall environmental performance of advanced digestion was similar to conventional digestion, with the main difference being a decrease in the climate change potential and an increase in the abiotic depletion potential. Acidification and eutrophication categories showed similar performances in both conventional and advanced AD. The effect of PT in the AD scenarios was related to energy recovery, sludge transport requirements and nutrient loads in the sludge and supernatant after digestate dewatering. Considering the results, PT could be a useful strategy to promote sludge valorization and decrease the environmental burdens of sludge management in Chile compared to the current scenario.  相似文献   
229.
Decision-making for sediment management is a complex task that incorporates the selections of areas for remediation and the assessment of options for any mitigation required. The application of Multicriteria Analysis (MCA) to rank different areas, according to their need for sediment management, provides a great opportunity for prioritisation, a first step in an integrated methodology that finally aims to assess and select suitable alternatives for managing the identified priority sites. This paper develops a methodology that starts with the delimitation of management units within areas of study, followed by the application of MCA methods that allows ranking of these management units, according to their need for remediation. This proposed process considers not only scientific evidence on sediment quality, but also other relevant aspects such as social and economic criteria associated with such decisions. This methodology is illustrated with its application to the case study area of the Bay of Santander, in northern Spain, highlighting some of the implications of utilising different MCA methods in the process. It also uses site-specific data to assess the subjectivity in the decision-making process, mainly reflected through the assignment of the criteria weights and uncertainties in the criteria scores. Analysis of the sensitivity of the results to these factors is used as a way to assess the stability and robustness of the ranking as a first step of the sediment management decision-making process.  相似文献   
230.
Average 21st century concentrations of urban air pollutants linked to cardiorespiratory disease are not declining, and commonly exceed legal limits. Even below such limits, health effects are being observed and may be related to transient daytime peaks in pollutant concentrations. With this in mind, we analyse >52,000 hourly urban background readings of PM10 and pollutant gases throughout 2007 at a European town with legal annual average concentrations of common pollutants, but with a documented air pollution-related cardiorespiratory health problem, and demonstrate the hourly variations in PM10, SO2, NOx, CO and O3. Back-trajectory analysis was applied to track the arrival of exotic PM10 intrusions, the main controls on air pollutants were identified, and the typical hourly pattern on ambient concentrations during 2007 was profiled. Emphasis was placed on “worst case” data (>90th percentile), when health effects are likely to be greatest. The data show marked daytime variations in pollutants result from rush-hour traffic-related pollution spikes, midday industrial SO2 maxima, and afternoon O3 peaks. African dust intrusions enhance PM10 levels at whatever hour, whereas European PM incursions produce pronounced evening peaks due to their transport direction (across an industrial traffic corridor). Transient peak profiling moves us closer to the reality of personal outdoor exposure to inhalable pollutants in a given urban area. We argue that such an approach to monitoring data potentially offers more to air pollution health effect studies than using only 24 h or annual averages.  相似文献   
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