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101.
102.
Micro-evolutionary processes that underpin genetic and morphological variation in highly mobile pelagic vertebrates are virtually
unknown. Previous findings preferentially invoke vicariant isolation due to large-scale physical barriers such as continental
landmasses, followed by genetic drift. However increasingly, evidence for divergence by non-random processes (e.g. selection,
plasticity) is being presented. Wedge-tailed shearwaters are wide-ranging seabirds with breeding colonies located such that
they experience a variety of environmental pressures and conditions. Previous work on this species has provided evidence of
inter-colony divergence of adult morphology and foraging modes, as well as chick developmental patterns, suggesting that reinforcement
among colonies is possible. In order to evaluate the micro-evolutionary processes driving this observed variation, our study
compared patterns of gene flow with morphological and environmental variation among four colonies of wedge-tailed shearwater
breeding within the Indo-Pacific Ocean basin. Estimates of gene flow differed according to the genetic marker used; most likely,
this is a function of different mutation rates. Nuclear introns suggest that gene flow among wedge-tailed shearwater breeding
colonies within the Indo-Pacific Ocean basin is substantial, however microsatellite markers imply that gene flow is reduced.
In general, levels of genetic divergence were relatively low and did not correlate with geographic distance, morphological
distance or environmental differences (sea-surface temperature and chlorophyll a concentration) among colonies. We suggest that genetic drift alone is unlikely to be the major source of morphological variation
seen in this species. Instead, we propose that non-random processes (selection, plasticity) underpin morphological diversity
seen in this and possibly other seabird species. 相似文献
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107.
Satellite telemetry reveals behavioural plasticity in a green turtle population nesting in Sri Lanka
Peter Bradley Richardson Annette C. Broderick Michael S. Coyne Lalith Ekanayake Thushan Kapurusinghe Chandralal Premakumara Susan Ranger M. M. Saman Matthew J. Witt Brendan J. Godley 《Marine Biology》2013,160(6):1415-1426
Satellite transmitters were deployed on ten green turtles (Chelonia mydas) nesting in Rekawa Sanctuary (RS-80.851°E 6.045°N), Sri Lanka, during 2006 and 2007 to determine inter-nesting and migratory behaviours and foraging habitats. Nine turtles subsequently nested at RS and demonstrated two inter-nesting strategies linked to the location of their residence sites. Three turtles used local shallow coastal sites within 60 km of RS during some or all of their inter-nesting periods and then returned to and settled at these sites on completion of their breeding seasons. In contrast, five individuals spent inter-nesting periods proximate to RS and then migrated to and settled at distant (>350 km) shallow coastal residence sites. Another turtle also spent inter-nesting periods proximate to RS and then migrated to a distant oceanic atoll and made forays into oceanic waters for 42 days before transmissions ceased. This behavioural plasticity informs conservation management beyond protection at the nesting beach. 相似文献
108.
Bay scallops, Argopecten irradians, supported vibrant fisheries which subsequently collapsed, as such, they are a focus species for many restoration efforts along the Atlantic and Gulf coasts of the United States. The scallops’ preferred habitat, seagrass, has also dramatically declined, and some scallop populations have increased post-restoration despite reduced seagrass cover. This has led to the hypothesis that macroalgae may serve as suitable alternative habitats for bay scallops. This study is the first to compare demographic rates, such as long-term survival, growth, condition and reproductive potential of scallops between the native eelgrass, Zostera marina, and the introduced alga, Codium fragile. Although long-term survival was not different between habitats, results suggest site-specific and inter-annual variation in the impacts of Codium on scallop growth. While demographic rates did not differ in Shinnecock Bay, in Sag Harbor, growth and/or condition were significantly different between both vegetated habitats depending on the year. However, recruit density, size and condition did not vary significantly, adding to the complexity of this relationship. Despite potential site-specific and inter-annual differences, this study supports the hypothesis that habitats other than eelgrass can benefit bay scallops. 相似文献
109.
Warmer, more acidic water resulting from greenhouse gas emissions could influence ecosystem processes like bioerosion of calcifying organisms. Based on summer-maxima values (temperature = 26 °C; pH = 8.1) at a collection site in New York (40°56″ N, 72°30″ W), explants of the boring sponge Cliona celata Grant, 1826 were grown for 133 days on scallop shells in seawater ranging from current values to one scenario predicted for the year 2100 (T = 31 °C; pH = 7.8). High water temperature had little effect on sponge growth, survival, or boring rates. Lower pH slightly reduced sponge survival, while greatly influencing shell boring. At pH = 7.8, sponges bored twice the number of papillar holes and removed two times more shell weight than at pH = 8.1. Greater erosion resulted in weaker scallop shells. This study suggests that lower seawater pH may increase boring rates of C. celata in shellfish, with potentially severe implications for wild and farmed shellfish populations. 相似文献
110.
This paper explores how earthquake scientists conceptualise earthquake prediction, particularly given the conviction of six earthquake scientists for manslaughter (subsequently overturned) on 22 October 2012 for having given inappropriate advice to the public prior to the L'Aquila earthquake of 6 April 2009. In the first study of its kind, semi‐structured interviews were conducted with 17 earthquake scientists and the transcribed interviews were analysed thematically. The scientists primarily denigrated earthquake prediction, showing strong emotive responses and distancing themselves from earthquake ‘prediction’ in favour of ‘forecasting’. Earthquake prediction was regarded as impossible and harmful. The stigmatisation of the subject is discussed in the light of research on boundary work and stigma in science. The evaluation reveals how mitigation becomes the more favoured endeavour, creating a normative environment that disadvantages those who continue to pursue earthquake prediction research. Recommendations are made for communication with the public on earthquake risk, with a focus on how scientists portray uncertainty. 相似文献