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101.
Jill Wakefield 《Marine pollution bulletin》2010,60(3):323-333
The European Union’s Integrated Maritime Policy is intended in part to co-ordinate sectoral policies, to achieve joined-up thinking and action and overcome the inconsistency between policy approaches that has led to the degradation of European seas. An integrated governance would be relatively straight-forward if the different interests and actors were operating on the basis of shared values, but they are not. While the fisheries sector, whether large or small-scale, is driven by a commercial imperative which tends towards the greatest extraction of the resource possible, environmentalists would champion the removal of all human impacts, other than redress activity, as the optimum state for the ecosystem. However, the greatest impediment to an integrated approach is the failure to subject the EU’s Common Fisheries Policy to the objectives of the Integrated Maritime Policy. Instead, all decisions concerning fisheries will continue to be made in accordance with the Fisheries Regulation which demands exploitation of the fragile resource. Attention needs to be given to how EU fisheries policy is to acquire values beyond that of commercial extraction for immediate economic benefit so that it may cohere with objectives of the Integrated Maritime Policy and aid the regeneration of the seas. 相似文献
102.
One ‘2020 vision’ for fluvial geomorphology is that it sits alongside stream ecology and hydraulic engineering as a key element of an integrated, interdisciplinary river science. A challenge to this vision is that scientists from these three communities may approach problems from different perspectives with different questions and have different methodological outlooks. Refining interdisciplinary methodology is important in this context, but raises a number of issues for geomorphologists, ecologists and engineers alike. In particular, we believe that it is important that there is greater dialogue about the nature of mutually‐valued questions and the adoption of mutually‐acceptable methods. As a contribution to this dialogue we examine the benefits and challenges of using physical experimentation in flume laboratories to ask interdisciplinary questions. Working in this arena presents the same challenges that experimental geomorphologists and engineers are familiar with (scaling up results, technical difficulties, realism) and some new ones including recognizing the importance of biological processes, identifying hydraulically meaningful biological groups, accommodating the singular behaviour of individuals and species, understanding biological as well as physical stimuli, and the husbandry and welfare of live organisms. These issues are illustrated using two examples from flume experiments designed (1) to understand how the movement behaviours of aquatic insects through the near‐bed flow field of gravelly river beds may allow them to survive flood events, and (2) how an understanding of the way in which fish behaviours and swimming capability are affected by flow conditions around artificial structures can lead to the design of effective fish passages. In each case, an interdisciplinary approach has been of substantial mutual benefit and led to greater insights than discipline‐specific work would have produced. Looking forward to 2020, several key challenges for experimentalists working on the interface of fluvial geomorphology, stream ecology and hydraulic engineering are identified. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
103.
Thomas H. Shipley Jill M. Whitman Frederick K. Duennebier Lisa D. Petersen 《Earth and Planetary Science Letters》1983,64(2):257-275
An interpretation of the seismic stratigraphy and sedimentation history of the East Mariana Basin has been made using recently collected seismic reflection and refraction data. This Mesozoic(?) age basin, between the Marshall Islands and the Mariana Trench, is subdivided into three regions. The central region with about 1000 m of sediment probably records Jurassic to Late Cretaceous sedimentation of a pelagic biogenic and clay-rich section overlain by a thick section of mainly Cenozoic carbonates shed from nearby volcanic platforms. A western region is characterized by a thinner sediment cover and a shallower acoustic basement with a similar sedimentation history except that the upper section is thinner as a consequence of fewer nearby volcanic highs. Extensive Late Cretaceous mid-plate volcanics apparently masks the lower section and forms acoustic basement. The shallower eastern region (east of 157.5°E) contains WNW-trending ridges which may be either fracture zones or high-amplitude abyssal hills. The sedimentation appears controlled by the same factors as in the other regions but the area was bypassed by most Cenozoic basin-filling turbidites because of its elevation.The isostatistically corrected basement depths between the three regions suggest that the crust in the east may be substantially younger than in the rest of the East Mariana Basin, perhaps Cretaceous in age. This requires the existence of a tectonic boundary within the basin. 相似文献
104.
The regional patterns of change of temperature and rainfall that might accompany a global warming due to increased carbon
dioxide can be studied by experiments with theoretical models of the climate system, by reconstructing the climates of past
warm epochs, and by determining the anomalies of temperature and precipitation that prevailed during years or seasons when
the Arctic region was unusually warm. The current study pursues the last course, making use of the northern hemisphere meteorological
data record for the period 1931–1978. Hemispheric maps of anomalies of both temperature and precipitation are presented for
the 10 warmest Arctic seasons and years, and for differences between the 5 warmest and 5 coldest consecutive Arctic winters.
Wintertime anomalies are generally greatest and dominate in determining the annual averages. The hemispheric temperature anomalies
for these data sets are similar to those determined earlier by the first author (Williams, 1980) using 1900–1969 data, but
the precipitation anomalies (for North America alone) show more variation, partly due to the method of computing the anomalies.
Work reported here begun while a visitor to the National Center for Atmospheric Research.
The National Center for Atmospheric Research is sponsored by the National Science Foundation. 相似文献
105.
Suzanne B. Bricker Fred T. Mackenzie Jill S. Baron Jason R. Price 《Aquatic Geochemistry》2014,20(2-3):81-86
This special volume of aquatic geochemistry is dedicated to the memory of Owen Peterson Bricker III (1936–2011) and serves as a tribute to his life and career. Owen had a distinguished and productive research career in both academics at Johns Hopkins University (Fig. 1) and as a public servant with the Maryland Geological Survey, the US Environmental Protection Agency, and the US Geological Survey. He was a pioneer and leader in aqueous geochemistry, who applied a study approach that quantified mineral weathering reactions and equilibrium thermodynamic relations to better understand the chemical evolution of stream water in small watersheds. He will be especially remembered for his efforts to establish rigorous field studies in small catchments around the United States as a means of quantifying the sources of acid-neutralizing capacity that affect the chemical status and biological health of natural waters. Fig. 1
Owen in a Johns Hopkins University laboratory in the early years (~1965, note the tie!) 相似文献