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81.
This paper illustrates the potential impact of future climate change on the archaeological resource of river catchments, specifically in Britain, but with reference to other examples across the globe, when considering issues of generic applicability. It highlights an area of the environmental record often neglected by policy makers and environmental planners when considering the impact of climate change; where cultural heritage has been considered in the past, an emphasis has been placed on the historic built environment and major monuments. Through studying the recent past, particularly the last 1,000 years, geomorphologists and geoarchaeologists can add much empirical data to these debates concerning system response. In addition to the impact of the changing intensity and pattern of natural geomorphic processes, human response to climate change ranging from new farming practices through to the implementation of mitigation strategies to minimise the effects of increased flood frequency and magnitude could be equally as damaging to the archaeological record if not managed through informed decision making.  相似文献   
82.
J. Holden  T. P. Burt 《水文研究》2003,17(6):1227-1237
A key parameter used in wetland hydrological and landform development models is hydraulic conductivity. Head recovery tests are often used to measure hydraulic conductivity, but the calculation techniques are usually confined to rigid soil theory. This is despite reports demonstrating the misapplication of rigid soil theory to non‐rigid soils such as peats. Although values of hydraulic conductivity calculated using compressible techniques have been presented for fenland peats, these data have never, to the authors' knowledge, been compared with such calculations in other peat types. Head recovery tests (slug withdrawal) were performed on piezometers at depths ranging from 10 to 80 cm from the surface on north Pennines blanket peats. Results were obtained using both rigid and compressible soil theories, thus allowing comparison of the two techniques. Compressible soil theory gives values for hydraulic conductivity that are typically a factor of five times less than rigid soil calculations. Hydraulic conductivity is often assumed to decrease with depth in upland peats, but at the study site in the northern Pennines it was not found to vary significantly with depth within the range of peat depths sampled. The variance within depth categories was not significantly different to the variance between depth categories showing that individual peat layers did not have characteristic hydraulic conductivity values. Thus, large lateral and vertical differences in hydraulic conductivity over short distances create problems for modelling but may help account for the high frequency of preferential flow pathways within what is otherwise a low matrix hydraulic conductivity peat. Hydraulic conductivity was found to vary significantly between sampling sites, demonstrating that hillslope‐ or catchment‐scale variability may be more important than plot‐scale variability. Values for compressibility of the peats are also reported. These generally decline with depth, and they also vary significantly between sampling sites. There are implications for the way in which measurements of hydraulic conductivity and other properties of blanket peat are interpreted, as the effects of environmental change in one part of a peat catchment may be very different to those in another. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
83.
Indigenous peoples offer alternative knowledge about climate variability and change based on their own locally developed knowledges and practices of resource use. In this article we discuss the role of traditional ecological knowledge in monitoring and adapting to changing environmental conditions. Our case study documents a project to record the seasonal knowledge of the Miriwoong people in northern Australia. The study demonstrates how indigenous groups’ accumulate detailed baseline information about their environment to guide their resource use and management, and develop worldviews and cultural values associated with this knowledge. We highlight how traditional ecological knowledge plays a critical role in mediating indigenous individuals and communities’ understandings of environmental changes in the East Kimberley region of north-west Australia, and how these beliefs may influence future decision-making about how to go about adapting to climate change at a local level.  相似文献   
84.
85.
Well Conditioning in a Fluvial Reservoir Model   总被引:3,自引:0,他引:3  
This paper describes a method for conditioning an object model of a fluvial reservoir on facies observations. The channels are assumed parametrized at sections normal to their main channel direction. Projections of the observations on these sections generates a map suitable for drawing conditioning values. This map contains the information from every facies observation between two adjacent sections, enabling handling of any well path. Coupling between well observations is also discussed. The methodology is implemented and demonstrated in examples with complex wells.  相似文献   
86.
Canada     
Mr. Holden is in charge of the Freshwater Fisheries Laboratory at Pitlochry. He has been engaged in freshwater and marine pollution research, particularly on organochlorines, for many years and has organized collaborative studies for both the Organization for Economic Co-operation and Development (OECD) and the International Council for the Exploration of the Sea (ICES).  相似文献   
87.
The fecundity of Raja clavata in British waters   总被引:1,自引:0,他引:1  
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88.
The consequences of a postulated collision between planets in the early solar system have been investigated. At least one of the planets has been taken with a D/H ratio similar to that of Venus (0.016) and the temperature of the collision interface (3 × 106 K) triggers chain reactions in near-surface material beginning with D-D reactions. The initial composition of the reacting material is consistent with a silicate + ices surface and a hydrogen-helium-inert gas atmosphere. The reaction chain contains 284 reactions, plus reverse reactions, and 40 radioactive decay processes. When the pressure in the reacting region is sufficiently high the colliding planets are blown apart and the highly-processed material at the heart of the explosion mixes with less processed and unprocessed material from cooler parts of the system. Mixtures of materials are found to explain isotopic anomalies associated with oxygen, magnesium, neon, silicon, carbon and nitrogen. The local production of isotopic anomalies avoids the problems associated with other suggested explanations - in particular the observation of neon E, almost pure22Ne, assumed as the product of the decay of22Na with a half-life of 2.6 years.  相似文献   
89.
90.
The article describes a method of strip aerial triangulation using the Wild B8 plotter. The principal feature of the method is the transfer of exterior orientation of a camera by measurement of outer orientation parallel to successive airbases.  相似文献   
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