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221.
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Correlations between flash points and vapor pressures at 25 °C for pure organic compounds were investigated. It was found that classification of organic compounds according to their chemical-structural characteristics (e.g., functional groups) was necessary for the correlation study. Under this classification, linearity seems to be the most appropriate correlation to explain the relationship between the inverse of flash points (°K) and the logarithm of vapor pressures (mm Hg) at 25°C for pure organic compounds. A test study to evaluate the validity of a regression line as an estimation of an unknown flash point from a known vapor pressure was carried out with a data set containing 31 alkanes and aromatics; 55% of the flash points were predicted within ±5°Cand89% were within ±10°C. Within limits of ± 5 to 10°C the procedure is useful but should be improved. 相似文献
223.
Summary In the spring of 1981, Tufts University and the International Union for the Conservation of Nature began teaching the World
Conservation Strategy to environmentalists working at the local level. The fourteen-week course that they offered was the
first of a series of initiatives to increase public awareness of the need for local action toward the solution of global environmental
problems. The success of the first course has encouraged other groups to adapt it to their own social and ecological settings,
but there is a pressing need for even more public education. While several aids to teaching the World Conservation Strategy
are now being developed to give local conservation educators access to the Strategy, the initiative for bringing the World
Conservation Strategy to the public should continue to come from these local leaders.
Frank Thibodeau is an environmental biologist and policy analyst with MA and PhD degrees from Tufts University. He is currently
a Research Associate in the Department of Urban and Environmental Policy at Tufts, preparing a book on the World Conservation
Strategy as a foundation for local environmental initiative under the auspicies of IUCN and the World Wildlife Fund. In addition
to his writing and teaching related to the Strategy, he maintains an active research program examining the development of
national and international strategies for the preservation of genetic diversity.
Hermann H. Field, an urban planner and Fellow of the American Institute of Architects, was director of the Planning Office
of the Tufts-New England Medical Center in downtown Boston for 12 years. In 1972 he initiated and then directed a new graduate
department of Urban and Environmental Policy at Tufts University. Since 1978 he has been Professor Emeritus in Environmental
Planning there. In addition to continued involvement in his department he is active on a range of levels in conservation from
the local to the international, including membership on IUCN's Commission on Environmental Planning. 相似文献
224.
Manfred Niecke Andreas Krüger Peter Hauff Hermann Ellenberg Ralph Labes und Susanne Niecke 《Umweltwissenschaften und Schadstoff-Forschung》1998,10(1):3-14
Zusammenfassung Mit der Hamburger Protonenmikrosonde untersuchen wir den Quecksilbergehalt in Seeadlerfedern, die in Mecklenburg-Vorpommern
über Jahrzehnte gesammelt wurden. Anhand der Fundorte und Funddaten ist es m?glich, ein zeitliches und regional differenziertes
Bild der Quecksilberbelastung, die vorwiegend durch Hg-halrige Saargutbeizen in der Landwirtschaft verursacht wurden, zu erstellen.
Wir vergleichen die gefundenen Konzentrationen mit der ‘geogenen’ Grundbelastung, die an Federproben des vorigen Jahrhunderts
von Museumstieren ermittelt wurde.
相似文献
225.
Atmospheric lead and bromine in Germany: post-abatement levels,variabilities and trends 总被引:2,自引:0,他引:2
Lammel G Röhrl A Schreiber H 《Environmental science and pollution research international》2002,9(6):397-404
INTENTION, GOAL, SCOPE, BACKGROUND: Abatement measures since the 1970s have depleted lead and bromine levels in the atmosphere over large parts of Europe. Our knowledge of the atmospheric cycling of these elements while a several decade-long period of intensive mobilization reaches its end is incomplete. OBJECTIVE: We have characterized the trends in the atmospheric levels of Pb and Br and present-day temporal and spatial variabilities. METHODS: This was achieved by short-term (weeks) and long-term (years) measurements of particulate Pb and Br at various sites in Germany. Samples of atmospheric particulate matter were collected on filter membranes and analyzed by x-ray fluorescence. RESULTS AND DISCUSSION: Average Pb levels at rural and urban inland sites did not exceed concentrations in background aerosols, sampled at a Baltic Sea coastal site, by more than a factor of 3. Due to sea salt, bromide inland particulate Br levels are below those at a coastal site. There, non-sea salt Br, however, is significant as well. Urban Pb and Br levels are not necessarily higher than rural levels. The concentration levels have decreased in such a way that the previously common source, local vehicular traffic emissions, is no longer predominant. Regional rather than local sources have been increasingly determining the concentrations since the 1990s. This is more pronounced for Br than for Pb. We found indications for coal burning and long-range transport as significant Pb sources. For particulate Pb species, a range of ages (elapsed time since Pb emission) has been found. This range shows two maxima corresponding to characteristic times of 72 and 24 h. CONCLUSIONS: The (mean) atmospheric residence time of particulate Pb is longer than the residence time of Br, in particular in the wintertime. The chemical species contributing to atmospheric Pb should be addressed in future studies. RECOMMENDATION AND OUTLOOK: Clearly, despite effective abatement measures, atmospheric Pb will continue to be dominated by anthropogenic mobilization. The influence from long-range transport can be expected to decrease with the effectiveness of abatement programmes in neighbouring countries of the region. 相似文献
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230.
Sebastian Hermann Manuel Welsch Rebecka Ericsdotter Segerstrom Mark I. Howells Charles Young Thomas Alfstad Hans‐Holger Rogner Pasquale Steduto 《Natural resources forum》2012,36(4):245-262
This paper discusses climate, land, energy and water (CLEW) interactions in Burkina Faso. It shows that integrated assessments of resource use at the national level can provide important insights and benefits, especially for a resource constrained least developed country. Agricultural policy is shown to have strong implications for energy use, whereas energy policies are found to be strongly interrelated with water constraints. Without an integrated and coordinated approach, strategy and policy formulation efforts to increase energy, food and water security could become both incoherent and counter‐productive. 相似文献