全文获取类型
收费全文 | 55篇 |
免费 | 14篇 |
国内免费 | 10篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 4篇 |
地球物理 | 9篇 |
地质学 | 54篇 |
海洋学 | 3篇 |
天文学 | 5篇 |
综合类 | 1篇 |
自然地理 | 2篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2014年 | 4篇 |
2013年 | 5篇 |
2012年 | 3篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 7篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
排序方式: 共有79条查询结果,搜索用时 252 毫秒
41.
内蒙古东部晚中生代断陷煤盆地与伸展构造 总被引:1,自引:0,他引:1
晚侏罗世晚期至早白垩世,内蒙古东北部出现了一个裂断陷作用期,形成大量地堑、半地堑式断陷盆地,盆地之边缘为犁式正断层,部分可能是剥离断层,它们是伸展作用下的产物。在统一的区域伸展作用下形成的多数盆地具有一定类似的构造、地层及煤层格架,以及具有可比的沉积组合所构成的盆地充填序列。犁式正断层发育的全过程控制了盆地的形成和演化,也控制了煤层的展布方向、煤体的横向分带和纵向分区、煤层旋回结构及煤变质程度。 相似文献
42.
Horizontal velocity spirals with a clockwise rotation(downward looking) rate of 1.7?m-1, on average, were observed in the western and northern Yellow Sea from December 2006 to February 2007. With the observed thermal wind relation,the beta-spiral theory was used to explain the dynamics of spirals. It was found that the horizontal diffusion of geostrophic vortex stretching is likely to be a major mechanism for generating geostrophic spirals. Vertical advection associated with surface/bottom Ekman pumping and topography-induced upwelling is too weak to support these spirals. Strong wind stirring and large heat loss in wintertime lead to weak stratification and diminish the effects of vertical advection. The cooling effect and vertical diffusion are offset by an overwhelming contribution of horizontal diffusion in connection with vortex stretching. The Richardson number-dependent vertical eddy diffusivity reaches a magnitude of 10-4 m^2 s-1 on average. An eddy diffusivity of 2870 m^2 s-1 is required for dynamic balance by estimating the residual term. This obtained value of 10-4 m^2 s-1 is in good agreement with the estimation in terms of observed eddy activities. The suppressed and unsuppressed diffusivities in the observation region are 2752 and 2881 m^2 s-1, respectively, which supports a closed budget for velocity rotation. 相似文献
43.
针对辽河盆地新生代拉张多期性的特点,提出一种适用于多期拉张盆地构造热演化模拟的纯剪切模型.该模型考虑了多期拉张的继承性、横向不均匀性以及拉张速率的可变性。通过几种拉张速率模式的对比,指出拉张速率模式的选择对模拟年轻盆地热演化过程具有重要意义.最后,利用该模型模拟研究了辽河盆地新生代的构造热演化历史. 相似文献
44.
Relic UHP Structures in Dabie-Sulu Region, China:Structural Expression and Geodynamic Significance 总被引:3,自引:0,他引:3
Suo Shutian Zhong Zengqiu You Zhendong Zhou Hanwen Faculty of Earth Sciences China University of Geosciences Wuhan China 《中国地质大学学报(英文版)》2000,11(3)
INTRODUCTIONIn recent years a num ber of detailed m ineralogical- petro-logical studies have been carried out on the UHP and HPmetamorphic belts in the Dabie- Sulu region,central China(see review papers by Jahn,1999;Ernst and L iou,1999;Wallis et al.,1999;Hacker et al.,1996 ;L iou et al.,1996 ;Cong et al.,1994) . Various tectonic evolution models for theUHP belt in the Dabie- Sulu region have been constructed(e.g.,Webb etal.,1999;Hacker et al.,1996 ;Cong et al.,1994) .However,as … 相似文献
45.
根据构造学及岩石学研究并结合已有同位素年代学资料地质意义分析证明, 现在观察到的大别-苏鲁超高压变质带的区域构造框架, 主要是在三叠纪中朝与扬子克拉通碰撞期后(200~170 Ma) 伸展体制和角闪岩相条件下形成的. 残余的同碰撞及超高压构造只保留在较大的榴辉岩及其他超高压变质岩体内部. 以湖北省麻城县乘马岗和何家湾、安徽省岳西县碧溪岭及江苏省东海等地区的榴辉岩为例, 分析描述了具弱面理的块状榴辉岩、超高压剪切带和A型褶皱等残余超高压构造. 强调指出, 只是这些早期的构造记录才反映大陆碰撞阶段的构造环境及相对运动学特征. 据此提出一个运动学模型, 表示三叠纪(240~210 Ma) 扬子克拉通向北俯冲于中朝克拉通之下并与其发生斜向碰撞的动力学格局. 相似文献
46.
点光源照射的亮度不均匀使获得的海底视像图像的灰度分布极不均匀 ,给海底多金属结核矿物的颗粒自动识别、粒径测量、储量的计算带来误差。本文针对点光源照射的多金属结核海底视像图像 ,提出了 3种方法进行灰度不均匀校正 ,并作了比较。实验结果表明 ,统计原图灰度值的二维分布特性 ,用二阶三次多项式函数拟合此灰度分布 ,再逐像元进行灰度位伸的方法能更有效地消除点光源对海底视像图像灰度的影响。 相似文献
47.
The deformation parameter (DP), which is defined as the product of shear deformation and stretching deformation of moisture flux circulation, is introduced. The tendency equation of DP is derived in pressure coordinates. Furthermore, DP is used to diagnose the deformation character of moisture flux circulation in the periphery of Bilis. The analysis showed that before Bilis landed, DP presented eight abnormal areas, which distributed alternately and closely encircled the low-pressure center. This indicated that the moisture flux circulation in the periphery of Bilis rotated counterclockwise and stretched longitudinally and latitudinally to deform. After Bilis landed, DP weakened gradually and its regular pattern of horizontal distribution loosened. The shear and stretching deformations of moisture flux circulation surrounding Bilis weakened after the typhoon landed. The deformation of moisture flux circulation in the periphery of Bilis mainly appeared in the middle-lower troposphere. There existed 1/2 phase difference between the shear and stretching deformations in the vertical-latitudinal cross section and aπ/4 phase difference between them on the horizontal plane. As Bilis landed and further moved inland of China, the intensities of DP, shear and stretching deformations decreased, meanwhile their vertical and horizontal structures became irregular. The chief dynamic factors responsible for the deformation of moisture flux circulation in the periphery of Bilis were the three terms associated with the three-dimensional advection transportation of DP, square difference between shear and stretching deformations coupling with Coriolis parameter, and horizontal gradient of geopotential height before Bilis landed. The last two dynamic factors impacted jointly on the deformation of moisture flux circulation after Bilis landed. 相似文献
48.
Friedemann Baur Ralf Littke Hans Wielens Carolyn Lampe Thomas Fuchs 《Marine and Petroleum Geology》2010
The Jeanne d'Arc basin, on the Grand Banks offshore Newfoundland, is a confined, failed-rift basin. Its initial development and burial history were controlled by crustal stretching and thinning. This study provides a detailed analysis of the heat flow-, tectonic subsidence-, stretching factor-, maturation- and temperature history, based on 44 1D models- and one full 4D (space and time) model. 相似文献
49.
苏北盆地高邮凹陷边界断裂带构造特征及成因 总被引:1,自引:0,他引:1
真武、吴堡断裂带是高邮凹陷的边界断裂带,具有复杂的结构和演化特征。通过三维地震资料解释以及断层平均活动速率的计算,分析了两断裂带在晚白垩世-新生代时期的几何学和运动学特征,将两断裂带作为一个整体,建立了凹陷边界主断裂发育的时空关系,对比探讨了两断裂带内各级断层的发育顺序和模式,并探讨了断层发育的成因。研究表明:一级断裂真①、吴①断层形成于泰州组沉积时期,阜四段沉积时期达到活动顶峰。二级断裂真②、吴②断层形成于阜四段沉积时期,戴南组沉积时期达到活动的顶峰。二级断裂主要形成于一级断裂沿走向的转折处,其延伸方向受控于区域早期NW-SE向伸展应力以及曲折边界条件;两断裂带内部断层发育模式有很大不同,认为其分别形成于伸展机制与斜滑机制下,与区域后期EW向挤压导致的郯庐断裂带右旋走滑作用有关。 相似文献
50.
Manuel Núñez 《地球物理与天体物理流体动力学》2013,107(6):633-641
The processes involved in the transformation of kinetic into magnetic energy in partially ionized compressible plasmas are not limited to the well-known mechanism of transport and diffusion of single-fluid magnetohydrodynamics. The induction equation, in this new case, may be written for any mean of the ion and electron velocities, and it possesses a natural scaling parameter equal to the ratio of the electron and ion masses. This produces a hierarchy of sources able to generate a magnetic field. The first of these sources corresponds to the classical stretching of magnetic field lines by the flow and ohmic diffusion, and a compressional effect due to the flow of electromagnetic energy into the regions of higher density. A potentially important effect is caused by dragging of electrons by neutral particles through collisions; this term could dissipate as well as enhance the magnetic field depending on the geometry of the neutral flow. Finally, there exists a term analogous to the stretching one, this time involving the current density and with the opposite effect. Its presence implies that not only the magnetic field but also the current density grows at most exponentially with a growth rate bounded by the maximum of the strain matrix. While the effect of these nonclassical sources, acting alone, is in all probability extremely small, they could be relevant in the creation of seed magnetic fields for subsequent dynamo action. 相似文献