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211.
Fritz Kleinschroth R. Scott Winton Elisa Calamita Fabian Niggemann Martina Botter Bernhard Wehrli Jaboury Ghazoul 《Ambio》2021,50(1):125
Invasions of water bodies by floating vegetation, including water hyacinth (Eichhornia crassipes), are a huge global problem for fisheries, hydropower generation, and transportation. We analyzed floating plant coverage on 20 reservoirs across the world’s tropics and subtropics, using > 30 year time-series of LANDSAT remote-sensing imagery. Despite decades of costly weed control, floating invasion severity is increasing. Floating plant coverage correlates with expanding urban land cover in catchments, implicating urban nutrient sources as plausible drivers. Floating vegetation invasions have undeniable societal costs, but also provide benefits. Water hyacinths efficiently absorb nutrients from eutrophic waters, mitigating nutrient pollution problems. When washed up on shores, plants may become compost, increasing soil fertility. The biomass is increasingly used as a renewable biofuel. We propose a more nuanced perspective on these invasions moving away from futile eradication attempts towards an ecosystem management strategy that minimizes negative impacts while integrating potential social and environmental benefits.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01360-6) contains supplementary material, which is available to authorized users. 相似文献
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Hudson’s Bay Company records were used to estimate the 1786–1911 annual number of moose (Alces alces andersonii) and caribou (Rangifer tarandus caribou) involved in trade by northern Ojibwa natives to the company post at Osnaburgh House (51°10′N 90°15′W) in northwest Ontario,
Canada. The human population for the early 19th century, and the number and severity of human starvations from 1786 to 1911
were estimated. The extent of forest fires in the region around Osnaburgh was documented using a “fire-day” index computed
from Hudson’s Bay Company journals and using qualitative archival information. It is argued that the human population was
too small to have caused the observed early 19th century moose and caribou population decline solely through predation. Likewise,
severe early 19th century famines were caused by climatic factors rather than by declines in moose and caribou numbers. Habitat
change caused by increased forest fires correlates with the observed decline of caribou, while moose increased and subsequently
collapsed as winter shelter was destroyed. A burgeoning human population, sustained during winter food shortages on potatoes
donated by the Hudson’s Bay Company, then kept ungulate populations to low levels until the late 19th century. Only then did
maturing forests and a new outbreak of fires provide renewed habitat for resurgences of, respectively, caribou and moose. 相似文献
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Due to Mediterranean, continental and oceanic influences we find in Northeastern Greece an exceptionally rich flora and fauna. Distributed over a distance of only 60–70 km from sea level northward to the Rhodopi mountains (with very cold and snowy winters at a height of 1000 m to 1600 m near the Bulgarian border) emerges a complex sequence of biozones unparalleled in a comparably small area in Europe. The low population density and the poor development of industry has allowed some natural landscapes to remain relatively undisturbed. The wetlands, including lake Kerkini and lake Vistonis as well as the deltas of the rivers Nestos and Evros, are a home or hibernating place for a large avifauna that includes vanishing bird species. In the oak‐ and beech‐forests of Rhodopi mountains, unusually rich in flowers, e.g. orchids, most of the large European mammals, including bear, wolf and wild boar, as well as birds of prey still find a basis for living. Pollution and damming of waters, erosion, cutting of riparian forests and overgrazing by domesticated animals are among other serious threats to the whole area. Problems, tasks and possibilities for protecting these zones of extraordinary quality are to be discussed along with an ecodevelopment concept for the whole region. 相似文献
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Fritz BG 《Journal of the Air & Waste Management Association (1995)》2006,56(8):1108-1114
Previous bench-scale experiments have provided data necessary for the development of empirical models that describe aerosol entrainment from bubble bursting. However, previous work has not been extended to non-Newtonian liquid slurries. Design of a waste treatment plant on the Hanford Site in Washington required an evaluation of the applicability of these models outside of their intended range. For this evaluation, aerosol measurements were conducted above an air-sparged mixing tank filled with simulated waste slurry possessing Bingham plastic rheological properties. Three aerosol-size fractions were measured at three sampling heights and for three different sparging rates. The measured entrainment was compared with entrainment models. One model developed based on bench-scale air-water experiments agreed well with measured entrainment. Another model did not agree well with the measured entrainment. It appeared that the source of discrepancy between measured and modeled entrainment stemmed from application beyond the range of data used to develop the model. A possible separation in entrainment coefficients between air-water and steam-water systems was identified. A third entrainment model was adapted to match experimental conditions and fit a posteri to the experimental data, resulting in a modified version that resulted in estimated entrainment rates similar to the first model. 相似文献
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