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排序方式: 共有174条查询结果,搜索用时 15 毫秒
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Summary In the laboratory, gynes (potential queens) of the paper wasp, Polistes fuscatus, exposed to both their natal nest and female nestmates (presumably their sisters) discriminate between female nestmates and unrelated females. However, gynes not exposed to their natal nest or conspecifics and gynes exposed only to female nestmates do not discriminate between female nestmates and unrelated females. Thus, the presence of the nest appears to be a requisite for the development of nestmate discrimination. 相似文献
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Seeking for Your Own Sake: Chinese Citizens’ Motivations for Information Seeking About Air Pollution
Janet Z. Yang 《Environmental Communication: A Journal of Nature and Culture》2019,13(5):603-616
Based on data from a Qualtrics panel, this study examines Chinese citizens’ motivations for information seeking about air pollution. Results from structural equation modelling indicate that information insufficiency, negative affect, attitudes toward seeking, and perceived information gathering capacity are positively related to information seeking. Informational subjective norms, however, were not significantly related to information seeking. Further, participants with more knowledge and higher risk perception were more likely to desire more information about air pollution. These results suggest that communication campaigns should highlight individuals’ personal risks and self-efficacy to encourage greater information seeking about air pollution among Chinese citizens. Emotional appeal may serve as an effective strategy as well. 相似文献
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Snelder TH Leathwick JR Dey KL Rowden AA Weatherhead MA Fenwick GD Francis MP Gorman RM Grieve JM Hadfield MG Hewitt JE Richardson KM Uddstrom MJ Zeldis JR 《Environmental management》2007,39(1):12-29
We describe here the development of an ecosystem classification designed to underpin the conservation management of marine environments in the New Zealand region. The classification was defined using multivariate classification using explicit environmental layers chosen for their role in driving spatial variation in biologic patterns: depth, mean annual solar radiation, winter sea surface temperature, annual amplitude of sea surface temperature, spatial gradient of sea surface temperature, summer sea surface temperature anomaly, mean wave-induced orbital velocity at the seabed, tidal current velocity, and seabed slope. All variables were derived as gridded data layers at a resolution of 1 km. Variables were selected by assessing their degree of correlation with biologic distributions using separate data sets for demersal fish, benthic invertebrates, and chlorophyll-a. We developed a tuning procedure based on the Mantel test to refine the classification's discrimination of variation in biologic character. This was achieved by increasing the weighting of variables that play a dominant role and/or by transforming variables where this increased their correlation with biologic differences. We assessed the classification's ability to discriminate biologic variation using analysis of similarity. This indicated that the discrimination of biologic differences generally increased with increasing classification detail and varied for different taxonomic groups. Advantages of using a numeric approach compared with geographic-based (regionalisation) approaches include better representation of spatial patterns of variation and the ability to apply the classification at widely varying levels of detail. We expect this classification to provide a useful framework for a range of management applications, including providing frameworks for environmental monitoring and reporting and identifying representative areas for conservation. 相似文献
96.
Cherie V. Miller Janet M. Denis Scott W. Ator John W. Brakebill 《Journal of the American Water Resources Association》1997,33(6):1155-1171
ABSTRACT: A regional assessment of water quality in small streams was conducted within four areas of distinct physiography and lithology in the upper Potomac River Basin. The Potomac River is a major tributary to the Chesapeake Bay, and this study provides new insight on the relationships between nutrient concentrations in small streams and watershed characteristics within this river basin. Nutrient concentrations were compared to land-use data including categories for agriculture (cropland and pasture), urban areas, and forests. Among agricultural areas, streams draining areas of intense row cropping typically contained higher nitrate concentrations than did those draining pastures. Streams draining forested areas typically had the lowest nutrient concentrations. Streams in areas underlain by carbonate bedrock were more likely to contain elevated concentrations of inorganic nitrogen and potassium than did streams in areas underlain by fractured siliciclastic or crystalline rocks, and we suggest that this is a physical phenomenon related to high hydraulic conductivities in carbonate ground-water systems. The median nitrate concentrations were highest in the Great Valley portion of the Valley and Ridge physiographic province, particularly in watersheds that have both carbonate bedrock and intensive row cropping. Values of nitrate in these streams ranged up to 8.99 mg/L as nitrogen. The soluble phosphorus concentrations during baseflow were generally low in all sub-units, even in some settings with potential for high phosphorus inputs such as urban areas with municipal point sources or agricultural areas. The mobility of phosphorus in these environments may be hindered by adsorption and geochemical reactions. 相似文献
97.
Assessing the degree of evolutionary differentiation between a rare taxon and its relatives is critical from a biological perspective. Because funding and time are limited, conservation biologists need to set maintainance of truly unique pieces of biodiversity as a higher priority than maintenance of interesting populations of widespread species. Although many factors go into setting priorities, thorough assessment of evolutionary distinctiveness based on multiple lines of evidence is the most basic. We used isozyme characters to assess the distinctiveness of a purportedly rare taxon, Echinocereus engelmannii var. munzii (Munz's hedgehog cactus), from other common varieties of the same species. We sampled at least 15 individuals from one population in each of the three mountain ranges where E. e. var. munzii is present within the United States plus three corresponding desert populations of a more common variety. To test for clinal variation between mountain and desert populations, we sampled three elevationally intermediate populations in the San Bernardino Mountains. We recognized a total of 104 band patterns for nine enzyme systems. All nine enzyme systems yielded polymorphic zymograms. Although we found substantial intrapopulation variability, no significant isozymic differentiation was apparent among any of the sampled populations. Lack of such differentiation implies that the effects of selection or drift have not been felt or detected in these populations. In terms of these enzyme systems Echinocereus engelmannii var. munzii is not distinct from other members of the species. Although there is no evidence of isozymic distinction, morphological evidence should be included in any decisions to submerge this taxon. 相似文献
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Daniel H. Saltzman MD Celeste M. Krauss Janet M. Goldman Beryl R. Benacerraf 《黑龙江环境通报》1991,11(3):139-143
We report two cases of prenatal detection of lissencephaly by high-resolution ultrasound. The first case studied was referred for high-risk obstetrical management and serial antenatal ultrasounds because of a family history of lissencephaly in an unresolved chromosomal abnormality. Diagnosis of a smooth gyral pattern consistent with lissencephaly was made at 32 weeks' gestation. The second case was referred for prenatal ultrasound because of a size versus dates discrepancy. The ultrasound examination showed a smooth gyral pattern at 31.5 weeks. In light of this ultrasound finding, a fetal blood sample was obtained and a chromosomal abnormality reported, confirming the diagnosis. To our knowledge, these cases represent the first report of the sonographic prenatal diagnosis of cerebral agyria or lissencephaly. 相似文献