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11.
卡西尼号探测器携带了光学成像科学子系统(ISS: Imaging Science Subsystem), 在2004--2017年间拍摄了一些土星内卫星的图像. 部分图像中土星内卫星非常靠近土星环, 观测对象受土星环散射光影响导致测量精度差, 甚至无法测量. 由此提出一种适用于这类图像的背景消除算法, 可对受土星光环散射光影响的土星内卫星进行测量. 归算了7颗近环内卫星(土卫十(Janus)、土卫十一(Epimetheus)、土卫十五(Atlas)、土卫十六(Prometheus)、土卫十七(Pandora)、土卫三十二(Methone)和土卫四十九(Anthe))的70张ISS图像, 并与不消除散射光的方法进行了比较. 结果显示, 该方法至少可以提高43%的精度. 和喷气推进实验室的土星卫星历表\lk SAT415相比, 测量得到的赤经和赤纬方向的残差均值分别为0.72km和2.26km, 标准差分别为10.99km和11.36km. 相似文献
12.
环境保护地图集的设计创新——论《绍兴市环境保护地图集》的编制 总被引:3,自引:0,他引:3
环境保护地图集作为环境保护工作成果的系统总结 ,其作用越来越受到关注 ,认识到它是环境保护决策、环境规划、环境管理、环境监测与科研等必不可少的有效表现手段。本文从绍兴市环境保护地图集的编制研究着手 ,探讨数字地图制图技术与环境科学技术的结合形式. 相似文献
13.
文章介绍了该图集编制的背景及国内编纂情况,阐述了图集需遵循的设计原则和工艺流程,构思了图集每个版块的定位及内容组成。重点对图集在编纂过程中开本设计、结构设计、内容设计、排版和整饰设计等方面进行了剖析,并根据重庆本地历史文化展现的需要,进行了对应的设计。其中的结构编排设计、内容排版设计、图名设计、文字内容结构设计,及版式中使用的中华民族文化元素和重庆本地的文化元素的有机融合等方面,在同类作品中实现了多项创新。最后,分析总结了图集编纂中的问题和解决方法,为后续相关产品的设计与编制提供参考。 相似文献
14.
The Aït Attab syncline, located in the Central High Atlas, displays a curved geometry in plan view, and is considered as one of the most spectacular fold shapes in the Central High Atlasic belt. We conducted a paleomagnetic study in Jurassic-Cretaceous red beds to investigate the origin of this geometry. The Natural Remanent Magnetization (NRM) is dominated by a secondary magnetization carried by haematite with unvarying normal polarity that has been dated at about 100 Ma. The regional fold test performed in both limbs of the syncline is positive and the paleomagnetic vectors (after tectonic correction) are parallel throughout the curvature, indicating a negative oroclinal bending test. These results are inconsistent with previous works that consider the bent geometry of this syncline to result from subsequent distortion of originally NE–SW trending structures by rotation about a vertical axis. We interpret the NRM data to demonstrate that the changing trend of the Aït Attab syncline is a primary feature, resulting from the influence of pre-existing, NE–SW and E-W-striking extensional faults that developed during a strike-slip regime. Paleomagnetic results also reveal that the tilting observed in the sampled red beds is post Albian, probably linked to the Cenozoic inversion of the High Atlasic belt. 相似文献
15.
The southern Rif cordillera front, between Fes and Meknes, is formed by the Prerif Ridges, which constitute a thrust and fold belt, in contact with the Saïss foreland basin. Geological evidence and regional GPS network data support recent and active tectonics of this Alpine cordillera, with a top-to-the-S-SW motion with respect to stable Africa. A local non-permanent GPS network was installed in 2007 around Fes to constrain the present-day activity of the mountain front. Six GPS sites are located in the Prerif mountain front (jbel Thratt and jbel Zalarh), the Saïss basin and the foreland constituted by the tabular Middle Atlas. Measurements of the GPS network in 2007, 2009 and 2012, over a five year span, seem to indicate that this region is tectonically active and is subjected to significant horizontal motions: (i) a regional displacement toward the SW with respect to stable Africa, showing an average rate of 2 mm/yr; (ii) a southwestward convergent motion between the jbel Thratt with respect to the Saïss basin and the eastern Zalarh ridge, with an average rate of about 4 mm/yr; and (iii) moderate NNE–SSW divergent dextral motion between the Saïss basin and the northern front of the tabular Middle Atlas with an average rate of about 1–2 mm/yr. The regional southwestward motion is related to the activity of the NE–SW sinistral North Middle Atlas-Kert fault zone, which follows the Moroccan Hot Line. Convergence between the Prerif ridges, located at the southern edge of the Rif, and the Saïss basin is accommodated by ENE–WSW striking northward dipping reverse sinistral faults and south vergent folds. In addition, increasing deformation toward the western ridges is in agreement with the stepped mountain front and the development of the arched structures of the Prerif ridges. Normal faults located south of the Saïss basin are responsible for local extension. Whereas the most active deformation occurs in the southern front of the jbel Thratt near Fes, the Saïss foreland basin and the Middle Atlas foreland have only moderate to low tectonic activity, as evidenced by geological and GPS data. 相似文献
16.
Filiz Bilgili Hans-Jürgen Götze Roman Pašteka Sabine Schmidt Ron Hackney 《International Journal of Earth Sciences》2009,98(3):571-583
An unsolved problem of regional importance for both the evolution and structure of the Northwest German Basin is the existence
or non-existence of the so-called Bramsche Massif. Explaining the nature of this massif and the cause of a related strong,
positive Bouguer anomaly (Bramsche Anomaly) is critical. In the study described here, we tested an existing “intrusion model”
against a newer “inversion model” in the southern Northwest German Basin. In the intrusion model, the strongly-positive Bouguer
anomaly represents the gravity effect of an intrusion at depths between 6 and 10 km. More recent interpretations invoke tectonic
inversion rather than intrusion to explain increased burial and the low level of hydrocarbon maturity found in boreholes.
We tested these different interpretations by constructing 3D forward density models to 15 km depth. The intrusion model was
updated and adjusted to incorporate recent data and we also modelled pre-Zechstein structures using different scenarios. The
final model has a very good fit between measured and modelled gravity fields. Based on currently available seismic and structural
models, as well as borehole density measurements, we show that the positive Bouguer anomaly cannot be modeled without a high-density,
intrusive-like body at depth. However, further in-sight into the crustal structures of the Bramsche region requires more detailed
investigations.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
17.
《水文科学杂志》2013,58(6):971-984
Abstract The identification of the turbidity mechanisms in two karstic springs (Ribaa and Bittit) located in the Middle Atlas Plateau in Morocco was performed by means of correlation and spectral analyses applied to time series of rainfall, flow rates, and turbidity. Time series analyses of rainfall and discharges revealed high inertia and storage capacities of the karstic systems. However, the occurrence of turbidity in the springs proved independent of discharges. A causal relationship between rainfall and the occurrence of turbidity in the form of waves was established. Accordingly, turbidity was assumed to be related to the hydrodynamic conditions prevailing in the karst. Turbulent quickflows in the karst transmissive conduits, following heavy rainfall, are thought to provoke the resuspension of solid particles deposited in the conduits, as well as their transport towards outlets. An external origin has also been contemplated, concerning infiltration waters may be loaded with suspended matters washed from the watershed. 相似文献
18.
Hyunhee Park 《The Cartographic journal》2013,50(1):92-93
Abstract Gamepads and joysticks have the potential to improve spatial navigation in virtual globes, block diagrams and 2D maps. Digital school atlases, in particular, can become more engaging if support for gamepads and joysticks is added, as children and adolescents are very proficient at using these devices. The fusion of gaming devices and interactive school atlases offers interesting new use cases: teachers can control a digital wall map with a remote-control gamepad while lecturing from the front of the classroom, or students can explore maps on their personal computers using an enticing way to interact. This paper presents these use cases, the characteristics of the most common gaming devices, and discusses spatial navigation with gamepads and joysticks for globes, block diagrams and 2D maps. The ideas presented originated from the ongoing development of a new, interactive version of the Swiss World Atlas for schools. 相似文献
19.
Trevor I. Allen David J. Wald Paul S. Earle Kristin D. Marano Alicia J. Hotovec Kuowan Lin Michael G. Hearne 《Bulletin of Earthquake Engineering》2009,7(3):701-718
We present an Atlas of ShakeMaps and a catalog of human population exposures to moderate-to-strong ground shaking (EXPO-CAT)
for recent historical earthquakes (1973–2007). The common purpose of the Atlas and exposure catalog is to calibrate earthquake
loss models to be used in the US Geological Survey’s Prompt Assessment of Global Earthquakes for Response (PAGER). The full
ShakeMap Atlas currently comprises over 5,600 earthquakes from January 1973 through December 2007, with almost 500 of these
maps constrained—to varying degrees—by instrumental ground motions, macroseismic intensity data, community internet intensity
observations, and published earthquake rupture models. The catalog of human exposures is derived using current PAGER methodologies.
Exposure to discrete levels of shaking intensity is obtained by correlating Atlas ShakeMaps with a global population database.
Combining this population exposure dataset with historical earthquake loss data, such as PAGER-CAT, provides a useful resource
for calibrating loss methodologies against a systematically-derived set of ShakeMap hazard outputs. We illustrate two example
uses for EXPO-CAT; (1) simple objective ranking of country vulnerability to earthquakes, and; (2) the influence of time-of-day
on earthquake mortality. In general, we observe that countries in similar geographic regions with similar construction practices
tend to cluster spatially in terms of relative vulnerability. We also find little quantitative evidence to suggest that time-of-day
is a significant factor in earthquake mortality. Moreover, earthquake mortality appears to be more systematically linked to
the population exposed to severe ground shaking (Modified Mercalli Intensity VIII+). Finally, equipped with the full Atlas
of ShakeMaps, we merge each of these maps and find the maximum estimated peak ground acceleration at any grid point in the
world for the past 35 years. We subsequently compare this “composite ShakeMap” with existing global hazard models, calculating
the spatial area of the existing hazard maps exceeded by the combined ShakeMap ground motions. In general, these analyses
suggest that existing global, and regional, hazard maps tend to overestimate hazard. Both the Atlas of ShakeMaps and EXPO-CAT
have many potential uses for examining earthquake risk and epidemiology. All of the datasets discussed herein are available
for download on the PAGER Web page ().
T. I. Allen and M. G. Hearne—contracted through Synergetics Incorporated. 相似文献
20.
决策者和公众正在越来越多地关注气候变化带来的影响,而这需要更加丰富的、区域尺度上的当前和未来气候状况的精细信息.《图集》与IPCC第六次评估报告(AR6)第一工作组(WGI)报告中其他章节相协调,评估区域气候变化的观测、归因、预估的基本信息,并建立了在线交互图集系统.《图集》包含图集章节和交互图集两部分:图集章节基于新... 相似文献