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101.
The joint probability method (JPM) to estimate the probability of extreme sea levels (Pugh and Vassie, Extreme sea-levels from tide and surge probability. Proc. 16th Coastal Engineering Conference, 1978, Hamburg, American Society of Civil Engineers, New York, pp 911–930, 1979) has been applied to the hourly records of 13 tide-gauge stations of the tidally dominated Atlantic coast of France (including
Brest, since 1860) and to three stations in the southwest of the UK (including Newlyn, since 1916). The cumulative total length
of the available records (more than 426 years) is variable from 1 to 130 years when individual stations are considered. It
appears that heights estimated with the JPM are almost systematically greater than the extreme heights recorded. Statistical
analysis shows that this could be due: (1) to surge–tide interaction (that may tend to damp surge values that occur at the
time of the highest tide levels), and (2) to the fact that major surges often occur in seasonal periods that may not correspond
to those of extreme astronomical tides. We have determined at each station empirical ad hoc correction coefficients that take
into account the above two factors separately, or together, and estimated return periods for extreme water levels also at
stations where only short records are available. For seven long records, for which estimations with other computing methods
(e.g. generalized extreme value [GEV] distribution and Gumbel) can be attempted, average estimations of extreme values appear
slightly overestimated in relation to the actual maximum records by the uncorrected JPM (+16.7 ± 7.2 cm), and by the Gumbel
method alone (+10.3 ± 6.3 cm), but appear closer to the reality with the GEV distribution (−2.0 ± 5.3 cm) and with the best-fitting
correction to the JPM (+2.9 ± 4.4 cm). Because the GEV analysis can hardly be extended to short records, it is proposed to
apply at each station, especially for short records, the JPM and the site-dependent ad hoc technique of correction that is
able to give the closest estimation to the maximum height actually recorded. Extreme levels with estimated return times of
10, 50 and 100 years, respectively, are finally proposed at all stations. Because astronomical tide and surges have been computed
(or corrected) in relation to the yearly mean sea level, possible changes in the relative sea level of the past, or foreseeable
in the future, can be considered separately and easily added to (or deduced from) the extremes obtained. Changes in climate,
on the other hand, may modify surge and tide distribution and hence return times of extreme sea levels, and should be considered
separately.
Parts of this paper have been presented orally at the session “Geophysical extremes: scaling aspects and modern statistical
approaches” of the EGU General Assembly, Vienna, 2–6 April 2006. 相似文献
102.
103.
潮汐电站建库及运行方案分析 总被引:3,自引:0,他引:3
本文给出了几种要行的潮汐电站水库及运行方案,并就发电量,发电的连续性,发电量-价格比等指标进行了对比分析。对潮汐电站作调峰运行也进行了分析。 相似文献
104.
Based on field data of river discharge, tide, tidal bore, and riverbed topography, the characteristics of river discharge, the effect of river discharge on riverbed erosion and sedimentation, and the feedback effect of riverbed erosion and sedimentation on the tide and tidal bore in the Qiantang River are analyzed. The results show that the inter-annual and seasonal variation of river discharge in the Qiantang River is noticeable, while the seasonal distribution of river discharge tends to be un... 相似文献
105.
The published global ocean tide models show good agreement in deep oceans and exhibit differences in complex coastal areas, along with subsequent Ocean Tide Loading Displacement (OTLD) modeling differences. Meanwhile, OTLD parameters (amplitudes and phase lags) derived by Global Positioning System (GPS) Precise Point Positioning (PPP) approach need long time to converge to a stable state and show poor precision of S2, K1, and K2 constituents. Based on the fact that no constraint is imposed in the current kinematic solution, a new method is put forward, in which global ocean tide model predictions are taken as the priori information constraints to speed up the convergence rate and improve the accuracy of the GPS-derived OTLD parameters. First, the data of tide gauge from 01 January 2014 to 31 December 2016 are used to generate the harmonic parameters to evaluate the accuracy of six global ocean tide models and a regional ocean tide model (osu.chinesea.2010). Osu.chinesea.2010 model shows good agreement with the tide gauge results, while NAO99b model presents relatively large difference. The predictions from osu.chinesea.2010 and NAO99b model are employed as reference and the prior information, respectively. Second, continuous observations of 12 GPS sites during 2006–2013 in Hong Kong are collected to generate three dimensional OTLD amplitudes and phase lags of eight constituents using PPP with prior information constraints approach and harmonic analysis. Third, comparing the convergence time of eight constituents from PPP without and with priori information constraints approaches, the results show that the new method can significantly improve the convergence rate of OTLD amplitude estimates which obtain a certain level of stability seven years earlier than that derived by the PPP without priori information constraints. Precision of OTLD parameters derived by the new method is about 1 mm. By comparing with the precision of single PPP approach, the accuracy of eight constituents has been improved, especially for S2, K1, and K2 constituents. Finally, through comparing the different correction effects of OTLD estimates on the coordinates and their time series of the ground GPS stations, the results show that OTLD estimates derived by the new approach have similar influence as the osu.chinasea.2010 ocean tide model. The new method provides an effective means to improve the convergence and precision of the GPS-derived OTLD parameters, and achieve a similar correction as the high precision ocean tide model. 相似文献
106.
中国极地大地测量学十年回顾:1996-2006年 总被引:1,自引:0,他引:1
[STBZ][ZW(*][HT6H]〓收稿日期:.
*基金项目:[HT6SS][ZK(]国家自然科学基金项目“利用多源遥感数据监测南极冰貌地形及其动态变化研究”(编号:40606002);国家测绘局项目“南极考察地区基础测绘”(编号:1469990324229)资助[ZK)]
[HT6H]〓作者简介:[HT6SS](1939 ),男,江西广丰人,教授,博士生导师,主要从事极地测绘遥感信息学的研究.[WT6HZ]E mail:[WT6BZ] [ZW)]
[HT4F]
[HT5K](摘〓要:[HT5K]回顾了近10年来我国南北两极大地测量学在GPS、重力、验潮及合成孔径雷达干涉测量等方面的研究进展。具体介绍了以长城站、中山站和黄河站3个GPS观测站为依托,开展的板块运动、卫星定轨及极区大气环境监测方面的研究;GPS在埃默里冰架、格罗夫山及Dome A考察中的应用研究;长城站的高精度绝对重力及相对重力测量;中山站自动验潮站的建立;及合成孔径雷达干涉测量在南极内陆冰盖的应用研究等。 相似文献
107.
Modeling the Tide System of the East China Sea with GIS 总被引:2,自引:0,他引:2
This article describes systematic research on the tide dynamic system under the support of the Geographic Information System and ocean fluid dynamics model. Through the high-resolution numerical simulation, we found some previously unreported phenomena, such as a low tide amplitude zone of the M2 constituent near Zhoushan isles, a low tide amplitude zone of the K1 constituent near Taiwan island, and a circular flow point band. The results of this research also show that the formation of the tide system is affected by sea-bottom friction coefficient, topography under water, and shoreline morphology. The change of shoreline morphology and significant change of topography under water play important roles in the tide system. Under specified conditions on input tide waves, shoreline morphology has a dominant impact on the formation of the tide system. With the systematically reconstructed sea level and the coastal change of 30 periods since the Pleni Glacier, the evolution process of the tide system of the East China Sea was simulated. Based on the simulation analysis of relationships among topography, shoreline and tide flow, this study concludes that the characteristic of the tide dynamic system is a dominant influencing factor on the formation of large-scale sand ridge clusters. In this article, the integration of the Geographic Information System, tide numerical simulation system, and tide movement visualization system are discussed as an example for related studies. 相似文献
108.
109.
介绍了体应变观测潮汐因子和勒夫数 h2 之间的线性关系 ,h2 的变化幅度较体应变观测潮汐因子震前异常变化大 7.5倍。同时 ,昌平台剪应变观测潮汐因子 O1波与体应变观测潮汐因子M2 波震前异常有较好的一致性 ,研究钻孔应变观测潮汐因子的变化有可能是取得地震前兆的有效途径之一。 相似文献
110.