全文获取类型
收费全文 | 74篇 |
免费 | 6篇 |
国内免费 | 16篇 |
专业分类
测绘学 | 16篇 |
大气科学 | 24篇 |
地球物理 | 13篇 |
地质学 | 17篇 |
海洋学 | 8篇 |
天文学 | 14篇 |
综合类 | 3篇 |
自然地理 | 1篇 |
出版年
2022年 | 4篇 |
2021年 | 1篇 |
2019年 | 5篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 8篇 |
2010年 | 1篇 |
2009年 | 4篇 |
2008年 | 6篇 |
2007年 | 6篇 |
2006年 | 6篇 |
2005年 | 6篇 |
2004年 | 9篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有96条查询结果,搜索用时 218 毫秒
61.
62.
针对热带气旋观测中的敏感区域问题,用数值模拟的方法,以GRAPES-TCM为试验模式,对登陆中国的2个热带气旋“派比安”与“圣帕”进行了敏感性试验,并通过模拟其他4个热带气旋路径对试验结果进行了验证.结果显示,初始场的不确定性导致了热带气旋路径的不确定性,但初始场中涡旋场的变化对路径几乎没有影响,环境场中位于涡旋外、距... 相似文献
63.
64.
东营凹陷古近纪济阳群沙河街组内的介形虫化石在平面上的分布有多种形式;就介形虫化石本身的保存特征而言,壳体充填物有5大类型,壳体颜色丰富多彩。对介形虫化石保存特征进行成因探讨,有助于恢复古环境。 相似文献
65.
时间频率量的特征及其对时频系统建设的影响 总被引:2,自引:1,他引:1
分析了物理量测量中时间频率量的特点,主要有:时间的流逝性;其基准是自然基准;时间和频率既密切相关又有区别;时间频率具有最高的测量精细度(分辨率)与准确度;其计量标准可通过电磁波发播;其测量精确度与测量时间有关。另外,从基准、守时、授时、时间频率设备的研制、生产和队伍建设等方面阐发了这些特点对时间频率系统建设的影响。 相似文献
66.
Seth Sadofsky Kaj Hoernle Svend Duggen Folkmar Hauff Reinhard Werner Dieter Garbe-Schönberg 《International Journal of Earth Sciences》2009,98(4):901-913
New geochemical data from the Cocos Plate constrain the composition of the input into the Central American subduction zone
and demonstrate the extent of influence of the Galápagos Hotspot on the Cocos Plate. Samples include sediments and basalts
from Ocean Drilling Program (ODP) Site 1256 outboard of Nicaragua, gabbroic sills from ODP Sites 1039 and 1040, tholeiitic
glasses from the Fisher Ridge off northwest Costa Rica, and basalts from the Galápagos Hotspot Track outboard of Central Costa
Rica. Site 1256 basalts range from normal to enriched MORB in incompatible elements and have Pb and Nd isotopic compositions
within the East Pacific Rise MORB field. The sediments have similar 206Pb/204Pb and only slightly more radiogenic 207Pb/204Pb and 208Pb/204Pb isotope ratios than the basalts. Altered samples from the subducting Galápagos Hotspot Track have similar Nd and Pb isotopic
compositions to fresh Galápagos samples but have significantly higher Sr isotopic composition, indicating that the subduction
input will have a distinct geochemical signature from Galápagos-type mantle material that may be present in the wedge beneath
Costa Rica. Gabbroic sills from Sites 1039 and 1040 in East Pacific Rise (EPR) crust show evidence for influence of the Galápagos
Hotspot ∼100 km beyond the morphological hotspot track. 相似文献
67.
68.
It is well recognized that sea surface temperature (SST) plays a dominant role in the formation and intensification of tropical
cyclones. A number of observational/empirical studies were conducted at different basins to investigate the influence of SST
on the intensification of tropical cyclones and in turn, modification in SST by the cyclone itself. Although a few modeling
studies confirmed the sensitivity of model simulation/forecast to SST, it is not well quantified, particularly for Bay of
Bengal cyclones. The present study is designed to quantify the sensitivity of SST on mesoscale simulation of an explosively
deepening storm over the Bay of Bengal, i.e., Orissa super cyclone (1999). Three numerical experiments are conducted with
climatological SST, NCEP (National Center for Environmental Prediction) skin temperature as SST, and observed SST (satellite
derived) toward 5-day simulation of the storm using mesoscale model MM5. At model initial state, NCEP skin temperature and
observed SST over the Bay of Bengal are 1–2°C warmer than climatological SST, but cooler by nearly 1°C along the coastline.
Observed SST shows a number of warm patches in the Bay of Bengal compared with NCEP skin temperature. The simulation results
indicate that the sea surface temperature has a significant impact on model-simulated track and intensity of the cyclonic
storm. The track and intensity of the storm is better simulated with the use of satellite-observed SST. 相似文献
69.
度量映射方法在河流分维测算中的应用 总被引:1,自引:0,他引:1
应用TM卫星图像数据,根据对黑龙江省阿什河约80km河段、松花江及嫩江约2300km河段的分维研究。证明了在度量数列满足持邻性和等比收敛性的条件下。可以应用度量映射方法计算随机分形集的分维。研究表明,黑龙江省阿什河河段(约80km)的分维比松花江和嫩江河段(约2300km)的分维高;曲线的分维一定要与标度的变化区间联系起来,否则分维将失去可比性;河流的分维不仅与标度有关,还与矢量化时原图像的分辨率有关。 相似文献
70.
Consolidation and Break-up of the South American Platform in Southeastern Brazil: Tectonothermal and Denudation Histories 总被引:1,自引:0,他引:1
P.C. Hackspacher L.F.B. Ribeiro M.C.S. Ribeiro A.H. Fetter J.C. Hadler Neto C.E.S. Tello E.L. Dantas 《Gondwana Research》2004,7(1):91-101
The different tectonic stages that occurred at the end of the Proterozoic and during the Phanerozoic have an important bearing on the tectonothermal history of the South American Platform and its consolidation. Geochronological data (U/Pb monazite, 40Ar/39Ar whole rock) and apatite fission-track analysis, from Precambrian rocks of the southeastern Brazilian coastline, permit the modeling of a long-term thermal history of the crust and constrain variable denudation rates.Using these data, a temperature-time diagram reflects a period of accelerated exhumation during the end of the Brasiliano Orogeny, followed by long stability and reactivation of the platform during the Rifting Phase of the South Atlantic Ocean.U/Pb zircon and monazite (blocking temperature of ca. 650° C) data from a series of igneous bodies suggest that a tangential and transpressional tectonic regime occurred between 625 and 610 Ma. During the following escape tectonics, between 610 and 590 Ma the exhumation process indicates cooling rates of ca. 12°C/Ma. 40Ar/39Ar biotite ages between 540 and 510 Ma (ca. 300°C) and a corrected fission-track age on apatites (100°C) of 480 Ma indicate an exhumation event related to block tectonics with huge vertical displacement along shear zones.A long stabilization phase, with low exhumation, and cooling rate around 0.25°C/Ma was recorded from the Cambro/Ordovician to the Mesozoic. At 65 Ma an acceleration of the exhumation through denudation and reworking of the South American surface with cooling rate of 1.5°C/Ma is observed.The uplift of the Mantiqueira and Serra do Mar mountain ranges along the southeast Brazilian coastline works as a climatic barrier provoking lateral erosional processes causing long-term scarp retreat, combined with intense, but progressive denudation towards the continent. A denudation of 2.5 to 4 km was calculated for such processes. This lateral retreat of escarpments and flexural response can provide important insights regarding marginal isostatic uplift and the evolution of offshore sedimentary basins of southeast Brazil. 相似文献