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581.
In this article, we assess the human and economic hazard posed by tsunami waves generated from impacts of sub-2 km diameter
asteroids. Annually, on average, 182(+197/−123) people will be affected by impact-induced waves with a corresponding infrastructure
loss of $18(+20/−12)M/y. Half of the tsunami hazard stems from impactors with diameters less than 300 m. One near Earth asteroid
will survive atmospheric transit and strike somewhere into Earth’s oceans every 5880 years, on average. In the mean generic
scenario, the tsunami from the impact affects 1.1 million people and destroys $110B of infrastructure. 相似文献
582.
AXIOM: advanced X-ray imaging of the magnetosphere 总被引:1,自引:0,他引:1
Graziella Branduardi-Raymont Steve F. Sembay Jonathan P. Eastwood David G. Sibeck Tony A. Abbey Patrick Brown Jenny A. Carter Chris M. Carr Colin Forsyth Dhiren Kataria Steve Kemble Steve E. Milan Chris J. Owen Lisa Peacocke Andy M. Read Andrew J. Coates Michael R. Collier Stan W. H. Cowley Andrew N. Fazakerley George W. Fraser Geraint H. Jones Rosine Lallement Mark Lester F. Scott Porter Tim K. Yeoman 《Experimental Astronomy》2012,33(2-3):403-443
Planetary plasma and magnetic field environments can be studied in two complementary ways—by in situ measurements, or by remote sensing. While the former provide precise information about plasma behaviour, instabilities and dynamics on local scales, the latter offers the global view necessary to understand the overall interaction of the magnetospheric plasma with the solar wind. Some parts of the Earth’s magnetosphere have been remotely sensed, but the majority remains unexplored by this type of measurements. Here we propose a novel and more elegant approach employing remote X-ray imaging techniques, which are now possible thanks to the relatively recent discovery of solar wind charge exchange X-ray emissions in the vicinity of the Earth’s magnetosphere. In this article we describe how an appropriately designed and located X-ray telescope, supported by simultaneous in situ measurements of the solar wind, can be used to image the dayside magnetosphere, magnetosheath and bow shock, with a temporal and spatial resolution sufficient to address several key outstanding questions concerning how the solar wind interacts with the Earth’s magnetosphere on a global level. Global images of the dayside magnetospheric boundaries require vantage points well outside the magnetosphere. Our studies have led us to propose ‘AXIOM: Advanced X-ray Imaging of the Magnetosphere’, a concept mission using a Vega launcher with a LISA Pathfinder-type Propulsion Module to place the spacecraft in a Lissajous orbit around the Earth–Moon L1 point. The model payload consists of an X-ray Wide Field Imager, capable of both imaging and spectroscopy, and an in situ plasma and magnetic field measurement package. This package comprises a Proton-Alpha Sensor, designed to measure the bulk properties of the solar wind, an Ion Composition Analyser, to characterise the minor ion populations in the solar wind that cause charge exchange emission, and a Magnetometer, designed to measure the strength and direction of the solar wind magnetic field. We also show simulations that demonstrate how the proposed X-ray telescope design is capable of imaging the predicted emission from the dayside magnetosphere with the sensitivity and cadence required to achieve the science goals of the mission. 相似文献
583.
Navid Attary John W. van de Lindt Hussam Mahmoud Steve Smith Christopher M. Navarro Yong Wook Kim Jong Sung Lee 《Natural Hazards》2018,93(3):1295-1316
Resiliency of communities prone to natural hazards can be enhanced through the use of risk-informed decision-making tools. These tools can provide community decision makers key information, thereby providing them the ability to consider an array of mitigation and/or recovery strategies. The Center for Risk-Based Community Resilience Planning, headquartered at Colorado State University in Fort Collins, Colorado, developed an Interdependent Networked Community Resilience (IN-CORE) computational environment. The purpose of developing this computational environment is to build a decision-support system, for professional risk planners and emergency responders, but even more focused on allowing researchers to explore community resilience science. The eventual goal was being to integrate a broad range of scientific, engineering and observational data to produce a detailed assessment of the potential impact of natural and man-made hazards for risk mitigation, planning and recovery purposes. The developing computational environment will be capable of simulating the effects from different natural hazards on the physical and socioeconomic sectors of a community, accounting for interdependencies between the sectors. However, in order to validate this computational tool, hindcasting of a real event was deemed necessary. Therefore, in this study, the community of Joplin, Missouri in the USA, which was hit by an EF-5 tornado on May 22, 2011, is modeled in the IN-CORE v1.0 computational environment. An explanation of the algorithm used within IN-CORE is also provided. This tornado was the costliest and deadliest single tornado in the USA in the last half century. Using IN-CORE, by uploading a detailed topological dataset of the community and the estimated tornado path combined with recently developed physics-based tornado fragilities, the damage caused by the tornado to all buildings in the city of Joplin was estimated. The results were compared with the damage reported from field studies following the event. This damage assessment was done using three hypothetical idealized tornado scenarios, and results show very good correlation with observed damage which will provide useful information to decision makers for community resilience planning. 相似文献
584.
585.
Steven K. Rose Richard Richels Steve Smith Keywan Riahi Jessica Strefler Detlef P. van Vuuren 《Climatic change》2014,123(3-4):511-525
Climate policies must consider radiative forcing from Kyoto greenhouse gases, as well as other forcing constituents, such as aerosols and tropospheric ozone that result from air pollutants. Non-Kyoto forcing constituents contribute negative, as well as positive forcing, and overall increases in total forcing result in increases in global average temperature. Non-Kyoto forcing modeling is a relatively new component of climate management scenarios. This paper describes and assesses current non-Kyoto radiative forcing modeling within five integrated assessment models. The study finds negative forcing from aerosols masking (offsetting) approximately 25 % of positive forcing in the near-term in reference non-climate policy projections. However, masking is projected to decline rapidly to 5–10 % by 2100 with increasing Kyoto emissions and assumed reductions in air pollution—with the later declining to as much as 50 % and 80 % below today’s levels by 2050 and 2100 respectively. Together they imply declining importance of non-Kyoto forcing over time. There are however significant uncertainties and large differences across models in projected non-Kyoto emissions and forcing. A look into the modeling reveals differences in base conditions, relationships between Kyoto and non-Kyoto emissions, pollution control assumptions, and other fundamental modeling. In addition, under climate policy scenarios, we find air pollution and resulting non-Kyoto forcing reduced to levels below those produced by air pollution policies alone—e.g., China sulfur emissions fall an additional 45–85 % by 2050. None of the models actively manage non-Kyoto forcing for climate implications. Nonetheless, non-Kyoto forcing may be influencing mitigation results, including allowable carbon dioxide emissions, and further evaluation is merited. 相似文献
586.
African Inland Fisheries: Experiences with Co-Management and Policies of Decentralization 总被引:1,自引:1,他引:0
Roger Lewins Malloum Ousman Baba Emma Belal Steve Donda Abbagana Mamane Lamine 《社会与自然资源》2014,27(4):405-420
Most countries in Africa have promoted some form of decentralized fisheries management either as discrete co-management projects or as a component of broader decentralization processes that cut across other sectors. These initiatives were shaped by an international policy narrative that emphasises participation in decision making and development. A review of fisheries decentralization experiences in Cameroon, Niger, Nigeria, and Malawi reveals marked differences in purpose, strategy, and performance. In general, co-management projects are limited by their ability to scale up new practice and to maintain viable and representative management institutions. In other cases, the decentralization process is not well supported politically or locally or does not articulate with fisheries policy. Experiences of decentralization in other sectors provide useful lessons. Acknowledging the informal institutional environment or realpolitikof fisheries and the rural economy could provide opportunities to better manage and review the process of decentralization. 相似文献
587.
SST errors in the tropical Atlantic are large and systematic in current coupled general-circulation models. We analyse the growth of these errors in the region of the south-eastern tropical Atlantic in initialised decadal hindcasts integrations for three of the models participating in the Coupled Model Inter-comparison Project 5. A variety of causes for the initial bias development are identified, but a crucial involvement is found, in all cases considered, of ocean-atmosphere coupling for their maintenance. These involve an oceanic “bridge” between the Equator and the Benguela-Angola coastal seas which communicates sub-surface ocean anomalies and constitutes a coupling between SSTs in the south-eastern tropical Atlantic and the winds over the Equator. The resulting coupling between SSTs, winds and precipitation represents a positive feedback for warm SST errors in the south-eastern tropical Atlantic. 相似文献
588.
A combination of numeric hydrodynamic models, a large-clast inverse sediment-transport model, and extensive field measurements were used to discriminate between a tsunami and a storm striking Anegada, BVI a few centuries ago. In total, 161 cobbles and boulders were measured ranging from 1.5 to 830?kg at distances of up to 1?km from the shoreline and 2?km from the crest of a fringing coral reef. Transported clasts are composed of low porosity limestone and were derived from outcrops in the low lying interior of Anegada. Estimates of the near-bed flow velocities required to transport the observed boulders were calculated using a simple sediment-transport model, which accounts for fluid drag, inertia, buoyancy, and lift forces on boulders and includes both sliding and overturning transport mechanisms. Estimated near-bed flow velocities are converted to depth-averaged velocities using a linear eddy viscosity model and compared with water level and depth-averaged velocity time series from high-resolution coastal inundation models. Coastal inundation models simulate overwash by the storm surge and waves of a category 5 hurricane and tsunamis from a Lisbon earthquake of M 9.0 and two hypothetical earthquakes along the North America Caribbean Plate boundary. A modeled category 5 hurricane and three simulated tsunamis were all capable of inundating the boulder fields and transporting a portion of the observed clasts, but only an earthquake of M 8.0 on a normal fault of the outer rise along the Puerto Rico Trench was found to be capable of transporting the largest clasts at their current locations. Model results show that while both storm waves and tsunamis are capable of generating velocities and temporal acceleration necessary to transport large boulders near the reef crest, attenuation of wave energy due to wave breaking and bottom friction limits the capacity of storm waves to transport large clast at great inland distances. Through sensitivity analysis, we show that even when using coefficients in the sediment-transport model which yield the lowest estimated minimum velocities for boulder transport, storm waves from a category 5 hurricane are not capable of transporting the largest boulders in the interior of Anegada. Because of the uncertainties in the modeling approach, extensive sensitivity analyses are included and limitations are discussed. 相似文献
589.
The retail geography literature has long recognised the importance of spatial and catchment analysis to inform decision-making relating to store development. However, less attention has been directed to store development “in practice” and, more specifically, how location research and geographical knowledge is leveraged across the wider retail business – in particular informing the marketing function. Through the use of a semi-structured interview and focus group methodology involving approximately 40 location planning, property and marketing analysts, we find that while some larger retailers have established close links between store development and marketing functions in the exchange of catchment, customer, competitor and loyalty card data to inform local marketing, product ranging, promotional mailings and post-opening store performance reviews, this tends to be the exception rather than the rule. We suggest there is a need for location planners to develop their intra-organisational legitimacy to engender a culture of knowledge-sharing and challenge the departmentalised, silo cultures that exist within some retailers in order to better leverage geographical insights and assist in the realisation of appropriate customer propositions and marketing strategies. 相似文献
590.
Shaun Cole Will J. Percival John A. Peacock Peder Norberg Carlton M. Baugh Carlos S. Frenk Ivan Baldry Joss Bland-Hawthorn Terry Bridges Russell Cannon Matthew Colless Chris Collins Warrick Couch Nicholas J. G. Cross Gavin Dalton Vincent R. Eke Roberto De Propris Simon P. Driver George Efstathiou Richard S. Ellis Karl Glazebrook Carole Jackson Adrian Jenkins Ofer Lahav Ian Lewis Stuart Lumsden Steve Maddox Darren Madgwick Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2005,362(2):505-534