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421.
Integration of all available data in reservoir characterization is critically important. 2D mapping is a reliable and robust technique that allows integration of multiple secondary data, including geological and geophysical surfaces and maps, to generate realistic summaries of reservoir quality at each location in an area of interest with an associated measure of uncertainty. This is achieved in 2D mapping with a more straightforward implementation, requiring significantly less time and fewer resources than three-dimensional modelling. In this paper, we propose an approach for the empirical calculation and optimization of differential compaction maps by leveraging existing well control for the use in 2D mapping. Success of the proposal is demonstrated through tests of accuracy, precision and fairness of the local uncertainty distributions for 100 new stratigraphical wells drilled in the Christina Lake and Kirby East area. 相似文献
422.
Multidimensional Map Algebra: Design and Implementation of a Spatio-Temporal GIS Processing Language 总被引:3,自引:0,他引:3
Jeremy Mennis 《Transactions in GIS》2010,14(1):1-21
Due to the increasing volume of spatio-temporal data generated from remote sensing, sensor networks and computational simulation, there is a need for a generic, domain-independent framework for spatio-temporal data analysis. This research presents a generic set of data processing and manipulation tools for spatio-temporal raster data called multidimensional map algebra (MMA). MMA is an extension of conventional map algebra that operates not only on data that are two-dimensional in space but also on data that are: (1) one-dimensional in time; (2) both two-dimensional in space and one-dimensional in time; (3) three-dimensional in space; and (4) both three-dimensional in space and one-dimensional in time. MMA data types, neighborhoods, lags, and functions are presented, including rules for combining data types of different dimensionality within local, focal, and zonal functions. A prototype implementation in JAVA is provided as a demonstration and syntax specification for the functions. Challenges to continued development of MMA include performance and efficiency issues for processing very large multidimensional data sets. 相似文献
423.
Pleistocene sediments at Leet Hill, southern Norfolk are examined in terms of their sedimentary structures, palaeocurrent indicators, clast and heavy mineral lithology and litho- and morphostratigraphic position. Colour of the quartzite and vein-quartz clasts is used to differentiate the Bytham and the Kesgrave sands and gravels, with the Bytham sands and gravels having a significantly higher proportion of coloured material. The Kirby Cane sands and gravels are the lower sedimentary unit and were deposited by the Bytham river, which drained a catchment extending into central England. At Leet Hill, erosion of the Kesgrave Sands and Gravels by the Bytham river has given the Kirby Cane sands and gravels a distinctive lithological assemblage. Trace clast lithologies suggest that the Kesgrave Sands and Gravels in the region of Leet Hill were deposited in a coastal location with an input from northern sources as well as southern and Welsh sources diagnostic of the Thames catchment. The glaciofluvial Leet Hill Sands and Gravels were deposited by outwash from the Anglian Scandinavian ice sheet. Initially the flow direction of the outwash was determined by the Bytham river valley, but this changed to a southerly direction once the valley had been infilled. This paper provides the first indication of the location of the boundary (Early Pleistocene coastline) between the fluvial Kesgrave Sands and Gravels and the marine equivalent reworked by coastal processes, and demonstrates the way the pre-glacial relief initially controlled patterns of glaciofluvial sedimentation during the early part of the Anglian glaciation. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
424.
Eric N. Powell Roger Mann Kelsey M. Kuykendall M. Chase Long Jeremy R. Timbs 《Marine Ecology》2019,40(4)
A survey of the region eastward of Nantucket provided an opportunity to examine the cold temperate–boreal boundary along the high‐energy Great South Channel. Here described are the benthic macroinvertebrate community types encountered, with a focus on the influence of climate change on the range boundaries of the benthic biomass dominants and the potential existence of transient multiple stable states. The survey identified three primary community types. The shallowest sites were occupied by a surfclam‐dominated community, comprising an abundance of large (≥150 mm) surfclams, and a few common attached epibiota primarily attached to exposed surfclam shell. Two communities exist at intermediate depths, one dominated by submarket and small market‐size surfclams (<150 mm) and the other, created by mussel mats and their attendant epibiota, crabs, sea urchins, and other mobile epifauna. Mussels are a foundational species, establishing a hard‐bottom terrain conducive to these other denizens in soft‐bottom habitat. Cobbles were nearly ubiquitous, rocks were routinely recovered, and boulders were encountered occasionally. Slow growing attached epibionts were exceedingly rare and mobile epifauna were not obviously associated with these large sedimentary particles; nor were the surfclam or mussel communities. The frequency of barnacle scars suggests sediment scour under the high‐flow regime characteristic of the surveyed region, which voids the habitat potential of these sedimentary particles. The abundance of surfclam shell indicates that surfclams have inhabited the shoaler depths for an extended time; limited shell at deeper sites supports the inference from the absence of large animals that these sites are relatively newly colonized and represent further evidence of an offshore shift in range brought on by increasing bottom water temperatures. The dichotomous nature of the two primary community types at mid‐depths suggests that these two communities represent multiple stable states brought on by the interaction of an invading cold temperate species with the receding boreal fauna resulting in a transient intermingling of species, which, however, structure the habitat into exclusionary stable states rather than overlapping in a co‐occurrence ecotone. 相似文献
425.
Jeremy Severinsen Femke Reitsma Emir Hartato 《International journal of geographical information science》2019,33(8):1683-1701
Volunteered Geographic Information (VGI) has emerged as a large, up-to-date, and easily accessible data source. VGI can allow authoritative mapping agencies to undertake continuous improvement of their own data, adding a currency dimension previously unattainable due to high associated costs. VGI also benefits scientific and social research by facilitating quick and low-cost research data capture by the public. VGI, however, through its diversity of authorship, presents a quality assurance risk to the use of this data. This research presents a formulaic model that addresses VGI quality issues, by quantifying trust in VGI. Our ‘VGTrust’ model assesses information about a data author, and the spatial and temporal trust associated with the data they create, to produce an overall VGTrust rating metric. This metric is both easy to understand and interpret. A facilitated case study, ‘Building Our Footprints’ is presented which tests the feasibility of VGTrust model in a real-world data capture exercise run by Land Information New Zealand, New Zealand’s mapping organisation. By overcoming the trust issues in VGI, this research will allow the integration of VGI and authoritative data and potentially expand the application of VGI, thereby leveraging the power of the crowd for productive and innovative re-use. 相似文献
426.
Inshore fisheries are coming under increasing pressure to account for wider environmental impacts and relations with other users of marine space. However approaches to inshore fisheries management across Britain’s devolved governments are becoming even more strikingly divergent. While in England the century old local Sea Fisheries Committees are to be replaced with modernised structures, and in Scotland there are efforts to move to a locally driven management system, in Wales there has been a retreat from local co-management. Not only do the reforms pose ongoing challenges for good governance, not least in the handling of cross-scale interactions and user group participation, but they may also fall short in providing for systematic and full integration of fisheries and marine environmental management. 相似文献
427.
428.
Maurizio D'Anna Déborah Idier Bruno Castelle Gonéri Le Cozannet Jeremy Rohmer Arthur Robinet 《地球表面变化过程与地形》2020,45(8):1895-1907
Shoreline change is driven by various complex processes interacting at a large range of temporal and spatial scales, making shoreline reconstructions and predictions challenging and uncertain. Despite recent progress in addressing uncertainties related to the physics of sea-level rise, very little effort is made towards understanding and reducing the uncertainties related to wave-driven shoreline response. To fill this gap, the uncertainties associated with the long-term modelling of shoreline change are analysed at a high-energy cross-shore transport dominated site. Using the state-of-the-art LX-Shore shoreline change model, we produce a probabilistic shoreline reconstruction, based on 3000 simulations over the past 20 years at Truc Vert beach, southwest France, whereby sea-level rise rate, depth of closure and three model free parameters are considered uncertain variables. We further address the relative impact of each source of uncertainty on the model results performing a Global Sensitivity Analysis. This analysis shows that the shoreline changes are mainly sensitive to the three parameters of the wave-driven model, but also that the sensitivity to each of these parameters is strongly modulated seasonally and interannually, in relation with wave energy variability, and depends on the time scale of interest. These results have strong implications on the model skill sensitivity to the calibration period as well as for the predictive skill of the model in a context of future climate change affecting wave climate and extremes. © 2020 John Wiley & Sons, Ltd. 相似文献
429.
430.
Jeremy B. Platt 《Natural Resources Research》2007,16(3):263-275
Fuel prices in 2006 continued at record levels, with uranium continuing upward unabated and coal, SO2 emission allowances, and natural gas all softening. This softening did not continue for natural gas, however, whose prices
rose, fell and rose again, first following weather influences and, by the second quarter of 2007, continuing at high levels
without any support from fundamentals. This article reviews these trends and describes the remarkable increases in fuel expenses
for power generation. By the end of 2005, natural gas claimed 55% of annual power sector fuel expenses, even though it was
used for only 19% of electric generation. Although natural gas is enormously important to the power sector, the sector also
is an important driver of the natural gas market—growing to over 28% of the market even as total use has declined. The article
proceeds to discuss globalization, natural gas price risk, and technology developments. Forces of globalization are poised
to affect the energy markets in new ways—new in not being only about oil. Of particular interest in the growth of intermodal
traffic and its a little-understood impacts on rail traffic patterns and transportation costs, and expected rapidly expanding
LNG imports toward the end of the decade. Two aspects of natural gas price risk are discussed: how understanding the use of
gas in the power sector helps define price ceilings and floors for natural gas, and how the recent increase in the natural
gas production after years of record drilling could alter the supply–demand balance for the better. The article cautions,
however, that escalation in natural gas finding and development costs is countering the more positive developments that emerged
during 2006. Regarding technology, the exploitation of unconventional natural gas was one highlight. So too was the queuing
up of coal-fired power plants for the post-2010 period, a phenomenon that has come under great pressure with many consequences
including increased pressures in the natural gas market. The most significant illustration of these forces was the early 2007
suspension of development plans by a large power company, well before the Supreme Court’s ruling on CO2 as a tailpipe pollutant and President Bush’s call for global goals on CO2 emissions.
相似文献
Jeremy B. PlattEmail: |