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141.
Effects of Coffee Management Intensity on Composition, Structure, and Regeneration Status of Ethiopian Moist Evergreen Afromontane Forests 总被引:1,自引:0,他引:1
Kitessa Hundera Raf Aerts Alexandre Fontaine Maarten Van Mechelen Pieter Gijbels Olivier Honnay Bart Muys 《Environmental management》2013,51(3):801-809
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
142.
Bart D. Ostro Michael J. Lipsett Nicholas P. Jewell 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1313-1318
Some consequences of acute exposure to ozone are best measured In studies of human respiratory responses in controlled exposure chambers. These studies typically examine relationships between exposures to alternative pollutant concentrations and Indicators of lung function as measured by spirometry, such as forced expiratory volume In one second, FEV1 However, the association of respiratory morbidity with these changes In lung function is not well established. To gain a better understanding of the relationship between ozonerelated changes in pulmonary function and respiratory symptoms, data from several clinical studies have been reanalyzed. Logistic regression models were used to determine the quantitative relationship between changes in FEV1 and the probability of a mild or moderate lower respiratory symptom. Models were developed that corrected for repeated sampling of individuals and both population-averaged and subject-specific effects were determined. The results indicate the existence of a strong and consistent quantitative relationship between changes in lung function and the probability of a respiratory symptom. Specifically, a 10 percent reduction in FEV1 is associated with a 15 percentage point increase In the probability of a mild, moderate or severe lower respiratory symptom and a 6 percentage point increase in the probability of a moderate or severe lower respiratory symptom. 相似文献
143.
Johan Höjesjö Bart Adriaenssens Torgny Bohlin Christopher Jönsson Illka Hellström Jörgen I. Johnsson 《Behavioral ecology and sociobiology》2011,65(9):1801-1810
The main aims of this study were to investigate (1) the occurrence and strength of the shyness–boldness behavioural syndrome
in brown trout fry, (2) whether this syndrome is associated with paternal migratory life history, (3) whether fry survival
and growth in the wild is associated with paternal life history and/or boldness and (4) whether offspring performance showed
maternal effects. Nine female migratory trout were each crossed with one migratory and one resident male and the offspring
were raised in hatchery tanks until first feeding. The behavioural studies showed that fry that responded bold towards a novel
object also accepted a novel food item earlier and responded more aggressively towards their own mirror image. Principal component
analysis showed that this shyness–boldness syndrome (PC1) explained 34% of the behavioural variation. Offspring boldness was
not affected by paternal migratory life history, but significant effects of the female parent suggested maternal and/or genetic
effects. Deviations from this pattern (PC2), where some individuals behaved less aggressively and performed more approaches
to food, explained an additional 17% of the variation in behaviour, and was significantly influenced by length and paternal
migratory life history. Fry growth and survival in nature was not associated with boldness (PC1) or PC2, suggesting that alternative
behavioural strategies can be successful in nature. However, female parent effects on variation in fry size persisted over
the first growth period in the wild, suggesting that these effects may influence offspring fitness during early life when
major selection occurs. 相似文献
144.
A large number of states have issued guidance addressing the vapor intrusion pathway making it difficult to keep up with various policies and requirements. We have compiled and reviewed guidance from 35 states, half of which have issued documents within the last three years. A comparison of policies among states shows reasonable consistency in some areas—for example, 20 of 23 states that provide an exclusion distance for subsurface sources of chlorinated volatile organic compounds (VOCs) use a distance of 100 feet. However, more commonly, the policy decisions vary widely. Among states, indoor air screening concentrations for the same VOC vary by more than 2,000 times and subsurface screening concentrations vary by more than 2,000,000 times. These wide discrepancies suggest a need for communication and consensus building in order to increase consistency in the management of the vapor intrusion pathway. © 2012 Wiley Periodicals, Inc. 相似文献
145.
Mats Tysklind Albertus Bart T. C. Bosveld Patrik Andersson Eeske Verhallen Theo Sinnige Willem Seinen Christoffer Rappe Martin van den Berg 《Environmental science and pollution research international》1995,2(4):211-216
Induction of ethoxyresorufin-O-deethylase (EROD) activity and porphyrin accumulation shows different structure-activity relationships for different polychlorinated biphenyls (PCBs) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Interactions between the two responses can strongly influence the induction and activity of EROD. The results support the conclusion that there are nonadditive interactions between nondioxin-like PCBs and dioxin-like compounds. The interaction between EROD activity and the porphyrin biosynthesis makes the prerequisite of additivity in the toxic equivalency factor concept for environmental mixtures highly spurious. Inhibition of EROD activity caused by non-dioxin like compounds could have a significant impact on the value of EROD activity as a biomarker in the present methods of risk assessment for these compounds. 相似文献
146.
Bart D Ostro 《Journal of Environmental Economics and Management》1981,8(2):196-198
The large commitment of government resources for environmental protection has prompted concern for the ultimate fiscal incidence of environmental programs, including the federal wastewater treatment grant program. An earlier study of EPA Region VII (Iowa, Missouri, Kansas, and Nebraska) concluded that the federal grants are likely to redistribute income from the middle income classes to primarily the upper income classes. Using a similar methodology, this study shows that for the Boston metropolitan area, there is a substantial redistribution from upper to lower and middle income groups. 相似文献
147.
In situ bioremediation (ISB) melds an understanding of microbiology, chemistry, hydrogeology, and engineering into a strategy for planned and controlled microbial degradation of specific contaminants. ISB creates subsurface environmental conditions, typically through reduction oxidation manipulation, which induce the degradation of contaminants via microbial catalyzed biochemical reactions. In turn, the microbes produce enzymes that are utilized to derive energy and that are instrumental in the degradation of target chemicals. To accomplish this chain of events, the type of microorganisms, contaminant, and the geological conditions at the site must be considered. Since in situ conditions are manipulated by engineered means, the most important consideration is the ability to transmit and mix liquids in the subsurface. The Interstate Technology Regulatory Council (ITRC)–ISB Team has recently completed a guidance document that describes a systematic approach to ISB in groundwater. ITRC is a state‐led coalition of more than 40 states working together with industry and stakeholders to achieve regulatory acceptance of environmental technologies. © 2003 Wiley Periodicals, Inc. 相似文献
148.
Bart Wouters Marijn Nijssen Gertjan Geerling Hein Van Kleef Eva Remke Wilco Verberk 《Journal of Coastal Conservation》2012,16(1):89-99
Encroachment of tall grasses and shrubs in coastal dunes has resulted in loss of vegetation heterogeneity. This is expected
to have negative effects on animal diversity. To counteract encroachment and develop structural heterogeneity grazing is a
widely used management practice. Here, we aim to functionally interpret changes in vegetation composition and configuration
following grazing management on habitat suitability for sand lizards. Aerial photographs taken over a period of 16 years were
used to quantify changes in vegetation composition. A GIS-based method was developed to calculate habitat suitability for
sand lizards in a spatially explicit manner, encompassing differences in vegetation structure and patch size. From 1987 to
2003 dune vegetation shifted from small patches of moss and sand to larger patches covered by shrubs and grasses. Grazing
management did not have any significant effect on the overall level of heterogeneity, measured as habitat suitability for
sand lizards. However, on a more local scale highly suitable patches in 1987 were deteriorating whereas unsuitable patches
became more suitable in 2003. This inversion results from a broad shift with shrubs being a limiting habitat element in 1987
to sandy patches being the limiting element in 2003. Future changes are believed to negatively impact sand lizards. The habitat
suitability model has proven to be a useful tool to functionally interpret changes in coastal dune vegetation heterogeneity
from an animal’s perspective. Further research should aim to include multiple species operating on different scale levels
to fully capture the natural landscape dynamics. 相似文献
149.
Bart De Keersmaecker Hilde Van Esch Dominique Van Schoubroeck Filip Claus Philippe Moerman Luc De Catte 《黑龙江环境通报》2013,33(3):292-295
We report the prenatal sonographic detection of a fetus with megalencephaly, polymicrogyria, postaxial polydactyly and hydrocephaly. Only 14 patients have been reported in the literature so far, all but one were diagnosed postnatally. The polymicrogyria in the frontoparietal lobe was confirmed by prenatal magnetic resonance imaging. Additionally, a hypoplastic thymus as seen in a 22q11 deletion was present. Although polymicrogyria along with pre-axial polydactyly has been described in 22q11 deletion, the diagnosis of Di George syndrome was ruled out. The etiology of megalencephaly, polymicrogyria, postaxial polydactyly and hydrocephaly has not been revealed yet. A dominant as well as recessive inheritance has been suggested. © 2013 John Wiley & Sons, Ltd. 相似文献
150.
Vyverman W Verleyen E Sabbe K Vanhoutte K Sterken M Hodgson DA Mann DG Juggins S Van de Vijver B Jones V Flower R Roberts D Chepurnov VA Kilroy C Vanormelingen P De Wever A 《Ecology》2007,88(8):1924-1931
There is a long-standing belief that microbial organisms have unlimited dispersal capabilities, are therefore ubiquitous, and show weak or absent latitudinal diversity gradients. In contrast, using a global freshwater diatom data set, we show that latitudinal gradients in local and regional genus richness are present and highly asymmetric between both hemispheres. Patterns in regional richness are explained by the degree of isolation of lake districts, while the number of locally coexisting diatom genera is highly constrained by the size of the regional diatom pool, habitat availability, and the connectivity between habitats within lake districts. At regional to global scales, historical factors explain significantly more of the observed geographic patterns in genus richness than do contemporary environmental conditions. Together, these results stress the importance of dispersal and migration in structuring diatom communities at regional to global scales. Our results are consistent with predictions from the theory of island biogeography and metacommunity concepts and likely underlie the strong provinciality and endemism observed in the relatively isolated diatom floras in the Southern Hemisphere. 相似文献