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31.
The growing commercial demand for products with medicinal use has caused overexploitation of several plant species worldwide. To prevent the decline of these populations, the collection of these resources should be done in a sustainable way considering the time of its replacement in natural stocks. This study was designed to identify the relationship between different intensities of extraction of bark from the trunk of Stryphnodendron rotundifolium Mart. and its regeneration speed. For this, we selected two areas of Cerrado in the Northeast of Brazil, where a monitoring experiment with duration of 24 months was performed. This experiment consisted in simulating different extractive damage to assess the regeneration of bark. In each area, we selected 20 individuals, among which four treatments with five repetitions were implemented. The data showed that in both study areas, the trees regenerated their shells faster when subjected to higher collection intensities. However, this regeneration was not related to variations in rainfall in the environment.  相似文献   
32.
Environment, Development and Sustainability - The human pressure on nature makes it imperative understanding how environmental issues can influence the world view of society. The aim of the current...  相似文献   
33.
Objectives: Proper roadside design is crucial in order to mitigate the consequences associated with single-vehicle run-off-road (SVROR) crashes. However, the Gulf Cooperation Council (GCC) region lacks in-depth, detailed information on its roadside design status. Hence, there is a need for an in-service evaluation of roadside design in the GCC region. The objective of this study is to assess the existing roadside design in a medium-sized, low-density city in the United Arab Emirates (UAE).

Methods: A multiyear crash database was used to identify 116 locations where SVROR injury crashes occurred between 2013 and 2016 in the city of Al Ain in the UAE. Visits to these locations were made in order to assess their roadside design. Subsequently, the collected data were analyzed. Roadside design was classified based on whether or not it deviated from roadside design guidelines. The guidelines adopted as a benchmark were those contained in the 2012 Abu Dhabi Department of Transport Roadside Design Guide (RDG) and/or those in the 2011 American Association of State Highway and Transportation Officials (AASHTO) RDG. It is worth stressing that local guidelines are heavily based on the 2011 AASHTO RDG.

Results: The study found that almost one quarter of all SVROR crashes resulted in injuries. The study also found that a staggering 80.17% of the SVROR injury crashes investigated occurred at locations where roadside design deviated from the benchmark. Lack of an adequate clear zone was the main cause of noncompliant locations. Most SVROR injury crash locations containing roadside design with deviations from the benchmark were located on roads with posted speed limits of 100 kph or higher. Light poles, trees, curbs, and barriers were the most harmful objects most often struck, and tree collisions accounted for the highest number of severe crashes. Ninety-four and 86% of all studied locations containing light poles and trees, respectively, were found to be noncompliant with the benchmark. Twenty-eight percent of all SVROR injury crashes involved a rollover. All rollovers were preceded by a collision with a tree, pole, guardrail, or curb. Forty-four percent of all rollover crashes resulted in severe injuries.

Conclusions: Significant revision of the existing roadside design not only in the area studied but throughout the UAE is recommended. The authors propose measures that may be useful in making roadside design in the area studied better align with the benchmark requirements.  相似文献   

34.
Potential toxic elements (PTE), in stream sediments, were used as contamination indicators for the definition of high-/low-grade spatial clusters in the Monfortinho area (Central Portugal). A set of 271 stream sediment samples was used for spatial modelling and further definition of rings of enrichment—high and low rings. A three-step multivariate statistical and geostatistical approach was used: (1) principal components analysis for PTE’s association evaluation and dimensionality reduction; (2) ordinary kriging as an unbiased interpolator for content inference and construction of a continuous representation of the considered attributes, at any arbitrary spatial location; (3) G clustering algorithm for the definition of high and low significance clusters. A moderate contamination in stream sediments is observed for almost all the considered PTE and a very high contamination for Ba, Cr and B. High contamination clusters are observed for Fe, Ni, Ba, Cu, B, Zn, V—northwest and southeast clusters—and for Cr—north and southwest clusters. The contamination degree index varies from moderate to high, which is mainly associated with the old mineralizations. The high computed rings often overlap the areas of abandoned Ba–Zn mineralization, as well as the sedimentary gold concentrations, along the Erges River banks. Tin and Cd spatial distribution may be related to former cassiterite exploitations in the survey area. Chromium is possibly connected with the schists. The definition of clusters with a PTE spatial enrichment will allow for the identification of contamination activities and therefore, the definition of adequate monitoring and mitigation actions.  相似文献   
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36.
Because many species have not been described and most species ranges have not been mapped, conservation planners often use surrogates for conservation planning, but evidence for surrogate effectiveness is weak. Surrogates are well‐mapped features such as soil types, landforms, occurrences of an easily observed taxon (discrete surrogates), and well‐mapped environmental conditions (continuous surrogate). In the context of reserve selection, the idea is that a set of sites selected to span diversity in the surrogate will efficiently represent most species. Environmental diversity (ED) is a rarely used surrogate that selects sites to efficiently span multivariate ordination space. Because it selects across continuous environmental space, ED should perform better than discrete surrogates (which necessarily ignore within‐bin and between‐bin heterogeneity). Despite this theoretical advantage, ED appears to have performed poorly in previous tests of its ability to identify 50 × 50 km cells that represented vertebrates in Western Europe. Using an improved implementation of ED, we retested ED on Western European birds, mammals, reptiles, amphibians, and combined terrestrial vertebrates. We also tested ED on data sets for plants of Zimbabwe, birds of Spain, and birds of Arizona (United States). Sites selected using ED represented European mammals no better than randomly selected cells, but they represented species in the other 7 data sets with 20% to 84% effectiveness. This far exceeds the performance in previous tests of ED, and exceeds the performance of most discrete surrogates. We believe ED performed poorly in previous tests because those tests considered only a few candidate explanatory variables and used suboptimal forms of ED's selection algorithm. We suggest future work on ED focus on analyses at finer grain sizes more relevant to conservation decisions, explore the effect of selecting the explanatory variables most associated with species turnover, and investigate whether nonclimate abiotic variables can provide useful surrogates in an ED framework.  相似文献   
37.
Wood resources are often used to support the needs of the local population. In order to protect biodiversity and resources, conservation strategies need to consider what types of wood use have the strongest impacts on forested areas. This study aimed to identify the use categories that put higher pressure on an Atlantic forest region located in the municipality of Igarassu in Pernambuco, northeastern Brazil. To conduct the study, we measured the volume of all wood products in 62 surveyed residences and registered the average replacement time for such products. The fuelwood category was most important locally and accounted for 92% of annual wood consumption. However, the construction category harvests more destructively and concentrates on the consumption of a few wood species. Therefore we recommend the fuelwood category to be the main focus of conservation effforts. In addition, the most important species for construction purposes (e.g., Eschweilera ovata (Cambess.) Miers, Apuleia leiocarpa (Vogel) J.F. Macbr. and Pogonophora schomburgkiana Miers ex Benth) should also be considered as a priority for conservation.  相似文献   
38.
This article focuses on developing a sustainable tourism in small Caribbean islands, defined here as those that have populations of fewer than 500,000. Such islands share a very fragile ecology and a high dependence on tourism. They differ in their degree of tourist penetration and visitor density and the related degree of environmental degradation. To explain the link between tourism intensity and ecological vulnerability, the so-called “destination life-cycle model” is presented. This suggests that islands pass through three primary stages of tourist development low-density exploration, rapid growth and consolidation, and high-density maturation involving the substitution of man-made for natural attractions. A broad empirical test of the model is performed through a quantitative examination of the tourism characteristics and visitor densities of a cross section of 23 small Caribbean islands. The three basic stages or tourism styles are identified: low-impact emerging areas, high-density mass-market mature destinations, and rapidly growing intermediate islands in between. Some broad strategies consistent with the systems framework for a sustainable tourism with moderate densitites are briefly explored. An earlier version of this article was presented to Caribbean Conservation Association Conference on Economics and the Environment. Barbados, West Indies, 6–8 November, 1989.  相似文献   
39.
Environment, Development and Sustainability - The activated biochar is a carbonaceous material obtained from thermal degradation of biomass with high adsorption potential. On the other hand, the...  相似文献   
40.
Plant domestication is an evolutionary process guided by human groups who modify the landscape for their needs. The objective of this study was to evaluate the phenotypic variations between populations of Spondias tuberosa Arruda (umbuzeiro) when subjected to different local landscape management strategies. The influence of the landscape management system on these populations was evaluated in five identified regional units (mountains, base of mountains, pastures, cultivated areas and home gardens). Ten individuals were randomly selected from each region and subjected to morphological and chemical fruit analysis. The diversity index, based on Simpson's index, was determined for the different populations. We then evaluated the morphological differences between the individual fruits from the distinct landscape areas. We observed no significant differences in morphological diversity between the areas studied. Our data suggest that the umbuzeiro specimens in this region may be in the process of incipient domestication.  相似文献   
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