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31.
Agricultural development in the Murcia autonomous region, Spain, has led to overexploitation of groundwater resources, and climate change will further increase pressures. Policy options to tackle the current unsustainable situation include the development of inter-basin water transfer (IBWT) schemes from wetter regions in the north and the introduction of taxation to further control groundwater abstraction. Under these scenarios, farmers with current access to water could face higher water cost, whereas farmers in areas where water was previously not available could see first time availability of water resources. In this paper, we combine discrete choice-based interviews with farmers in the Torrealvilla catchment, in which they indicate how they would adapt their land use under different scenarios, with an input–output model to assess the aggregate effects of individual land use decisions on the economy and water consumption of the Murcia region. The paper presents steps taken in the development of an input–output table for Murcia, including disaggregation of the agricultural sector, accounting for sector water use and consideration of back- and forward linkages. We conclude that appropriate taxation can lead to better water use efficiency, but that this is delicate as relatively small changes in prices of agricultural products can have significant impacts on land use and water consumption. Although new IBWT schemes would enable water to be used more efficiently, they would considerably increase regional water consumption and the regional economy’s dependence on water. As this is not sustainable under future climate change, water saving development pathways need to be explored.  相似文献   
32.
Maintaining drinking water quality is essential to water companies and their customers, and agricultural non-point source pollution is a major cause of water quality degradation. In this paper, we examine the potential use of payments financed by a water company as incentives for farmers to adjust their agricultural land management practices in order to protect water quality. We use a choice experiment (CE) to measure farmers’ minimum willingness to accept (WTA) requirements to adjust agricultural land management practices in Nidderdale and the Washburn valley (Yorkshire, UK) under a potential local payment for ecosystem services (PES) programme. Latent class analysis of farmers’ CE responses was used to quantify the size and spread of farmers’ preferences and minimum WTA values for compensation payments, and to investigate potential drivers of preference variation. Analysis suggested that the emphasis on sheep or cattle/dairy production within mixed farming businesses in this area provides a partial explanation for the considerable observed heterogeneity in preferences and minimum WTA requirements for participation in a potential PES programme.  相似文献   
33.
Farming communities are increasingly expected to manage their agricultural activities in ways that ensure sustainable flows of a wide range of ecosystem services for society. The land use and management choices that farmers make are dependent upon their socio-economic characteristics and background, and in turn have important implications for the landscape and associated ecosystem services. Thus, a better understanding about the linkages between the characteristics of farmers, farm management and land use is important for managing multifunctional agro-ecosystems. In this paper, we first develop a typology of farmers for Torrealvilla catchment in Murcia, Spain, according to the characteristics of their households and farm management (e.g. the farmer’s age, household income, water access, land tenure and farm labour). This analysis distinguishes six types of farmers. Secondly, we analyse the link between farmer typology and the farmers’ responses to a number of scenarios. The scenarios describe different likely changes to agriculture in the catchment in terms of environmental constraints (irrigation water availability and rainfall pattern) and environmental policy regulation (water taxation and subsidies). This exercise enables us to explore the range of future land use changes that are likely to occur in the study area. The results indicate that: rain-fed agriculture is expected to experience gradual but extensive abandonment; vegetable/fruit farming and pig/animal rearing are likely to stagnate or even decline; and growing of grapes is likely to expand. Thirdly, we qualitatively evaluate how future land use changes are likely to affect key ecosystem services in the study area including future agricultural production and associated local income generation, erosion control, maintenance of the groundwater table and various cultural services associated with a heterogeneous agro-ecosystem. Particular changes such as expansion of grape production will increase food production and local income at the cost of further depletion of the aquifer and increased risk of salinisation. The outcomes of the study highlight that, to be effective, the design of agri-environmental schemes and other government interventions (e.g. specific compulsory regulations on farming practices and associated water use) should carefully take into account the characteristics of the farmers within the area of interest, their land uses and the possible diversity of responses to policy and environmental drivers. Opportunities exist for future studies quantifying the extent of the impacts of ecosystem service provision through formal models combining farmers’ land use decision-making and spatially explicit modelling of landscape processes.  相似文献   
34.
Fauchald P  Mauritzen M  Gjøsaeter H 《Ecology》2006,87(11):2915-2924
The migration of large aggregations of animals that sweep through the landscape is a phenomenon with large consequences in many ecosystems. It has been suggested that such migrations are mediated by resource depletion. Under this hypothesis it has been shown that simple foraging rules may generate density-dependent migratory waves (DDMW) in which the speed and amplitude increase with animal abundance. We tested these predictions on a 32-year data set of the spatial distribution of the two youngest age groups of a small pelagic schooling fish, the capelin (Mallotus villosus), by the end of their annual feeding migration in the Barents Sea. Our data suggest that the two age groups divided the Barents Sea by forming migratory waves that moved in opposite directions. The aggregation and spatial displacement of these waves increased with increasing age-specific abundance. However, possibly through social interactions, migratory pattern was modified by the abundance of the other age group.  相似文献   
35.
Declines in amphibian populations and species biodiversity during the last decades has called for an assessment of possible threats to these animals. Polychlorinated biphenyls (PCBs) are known endocrine disrupting contaminants and are found in high levels in some populations of wild living amphibians. To evaluate the endocrine disrupting potential of PCBs in adult frogs, Aroclor 1,254 were subcutaneously injected into male European common frogs Rana temporaria. The injected doses ranged from 0.01 to 100 mg/kg body mass, resulting in liver concentrations between 74 and 133,619 microg/kg ww. After 14 days, serum testosterone (T), estradiol (E) and hepatic retinol (R) and retinylpalmitate (RP) were easured. No dose dependent effects were found on levels of hormones or retinoids. However, a significantly higher within-group variation in the E-T ratio in the exposed groups may indicate that the sex-hormone homeostasis of male R. temporaria is affected by PCBs shortly after arousal from hibernation, but that the effects are subtle and that several different mechanisms are involved. The lack of direct effect on T, E, R and RP may be due to the timing of exposure (shortly after arousal from hibernation), or due to a relatively short exposure time to Aroclor 1,254. Based on the results, we propose that future research should focus on effects of PCBs in relation to the different physiological phases frogs experience throughout the year (hibernation, reproduction etc.).  相似文献   
36.
Soil organic carbon (SOC) is one of the most important carbon stocks globally and has large potential to affect global climate. Distribution patterns of SOC in Denmark constitute a nation-wide baseline for studies on soil carbon changes (with respect to Kyoto protocol). This paper predicts and maps the geographic distribution of SOC across Denmark using remote sensing (RS), geographic information systems (GISs) and decision-tree modeling (un-pruned and pruned classification trees). Seventeen parameters, i.e. parent material, soil type, landscape type, elevation, slope gradient, slope aspect, mean curvature, plan curvature, profile curvature, flow accumulation, specific catchment area, tangent slope, tangent curvature, steady-state wetness index, Normalized Difference Vegetation Index (NDVI), Normalized Difference Wetness Index (NDWI) and Soil Color Index (SCI) were generated to statistically explain SOC field measurements in the area of interest (Denmark). A large number of tree-based classification models (588) were developed using (i) all of the parameters, (ii) all Digital Elevation Model (DEM) parameters only, (iii) the primary DEM parameters only, (iv), the remote sensing (RS) indices only, (v) selected pairs of parameters, (vi) soil type, parent material and landscape type only, and (vii) the parameters having a high impact on SOC distribution in built pruned trees. The best constructed classification tree models (in the number of three) with the lowest misclassification error (ME) and the lowest number of nodes (N) as well are: (i) the tree (T1) combining all of the parameters (ME = 29.5%; N = 54); (ii) the tree (T2) based on the parent material, soil type and landscape type (ME = 31.5%; N = 14); and (iii) the tree (T3) constructed using parent material, soil type, landscape type, elevation, tangent slope and SCI (ME = 30%; N = 39). The produced SOC maps at 1:50,000 cartographic scale using these trees are highly matching with coincidence values equal to 90.5% (Map T1/Map T2), 95% (Map T1/Map T3) and 91% (Map T2/Map T3). The overall accuracies of these maps once compared with field observations were estimated to be 69.54% (Map T1), 68.87% (Map T2) and 69.41% (Map T3). The proposed tree models are relatively simple, and may be also applied to other areas.  相似文献   
37.
In 2007 the Danish Working Environment Authority launched a new strategy to strengthen and qualify primary prevention of work related stress. Part of the strategy consists of increased inspections of the psychosocial working environment as well as the development and implementation of a new inspection tool, namely the “guidance tool”.Twenty-four sector specific guidance tools have been developed to help WEA inspectors assess psychosocial working environment problems in all Danish enterprises. Based on recent research, the guidance tools consist, in each sector, of the three to five most important risk factors (for example quantitative demands, emotional demands, and work related violence), as well as the most important preventive factors, e.g. quality of management, influence/control and training.During the first years of the strategy, an increasing number of inspectors have issued improvement notices regarding work related stress and violence, and there has been an increasing number of notices issued on several risk factors. For some aspects, the tools have helped increase the clarity and comprehensibility of the improvement notices and reduce the WEA’s time consumption per enterprise.The guidance tools seem to be a suitable and efficient way of assessing several health and safety risks concerning work related stress and violence thereby allowing the WEA to detect more of the existing problems. Future challenges projected for the strategy include continuously training all WEA inspectors in the proper use of the tools and continuously refining the tools – or developing new tools – based on further research and experiences from practice.  相似文献   
38.

Objective

This study aimed to assess the diagnostic yield of prenatal genetic testing using trio whole exome sequencing (WES) and trio whole genome sequencing (WGS) in pregnancies with fetal anomalies by comparing the results with conventional chromosomal microarray (CMA) analysis.

Methods

A total of 40 pregnancies with fetal anomalies or increased nuchal translucency (NT ≥ 5 mm) were included between the 12th and 21st week of gestation. Trio WES/WGS and CMA were performed in all cases.

Results

The trio WES/WGS analysis increased the diagnostic yield by 25% in cases with negative CMA results. Furthermore, all six chromosomal aberrations identified by CMA were independently detected by WES/WGS analysis. In total, 16 out of 40 cases obtained a genetic sequence variant, copy number variant, or aneuploidy explaining the phenotype, resulting in an overall WES/WGS diagnostic yield of 40%. WES analysis provided a more reliable identification of mosaic sequence variants than WGS because of its higher sequencing depth.

Conclusions

Prenatal WES/WGS proved to be powerful diagnostic tools for fetal anomalies, surpassing the diagnostic yield of CMA. They have the potential to serve as standalone methods for prenatal diagnosis. The study highlighted the limitations of WGS in accurately detecting mosaic variants, which is particularly relevant when analyzing chorionic villus samples.  相似文献   
39.
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