全文获取类型
收费全文 | 151篇 |
免费 | 34篇 |
国内免费 | 6篇 |
专业分类
测绘学 | 13篇 |
地球物理 | 68篇 |
地质学 | 57篇 |
海洋学 | 19篇 |
天文学 | 7篇 |
综合类 | 5篇 |
自然地理 | 22篇 |
出版年
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 7篇 |
2017年 | 9篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 9篇 |
2013年 | 9篇 |
2012年 | 16篇 |
2011年 | 5篇 |
2010年 | 7篇 |
2009年 | 9篇 |
2008年 | 8篇 |
2007年 | 12篇 |
2006年 | 11篇 |
2005年 | 5篇 |
2004年 | 6篇 |
2003年 | 4篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1988年 | 1篇 |
1987年 | 4篇 |
排序方式: 共有191条查询结果,搜索用时 31 毫秒
21.
Deconvolution is an essential step for high-resolution imaging in seismic data processing. The frequency and phase of the seismic wavelet change through time during wave propagation as a consequence of seismic absorption. Therefore, wavelet estimation is the most vital step of deconvolution, which plays the main role in seismic processing and inversion. Gabor deconvolution is an effective method to eliminate attenuation effects. Since Gabor transform does not prepare the information about the phase, minimum-phase assumption is usually supposed to estimate the phase of the wavelet. This manner does not return the optimum response where the source wavelet would be dominantly a mixed phase. We used the kurtosis maximization algorithm to estimate the phase of the wavelet. First, we removed the attenuation effect in the Gabor domain and computed the amplitude spectrum of the source wavelet; then, we rotated the seismic trace with a constant phase to reach the maximum kurtosis. This procedure was repeated in moving windows to obtain the time-varying phase changes. After that, the propagating wavelet was generated to solve the inversion problem of the convolutional model. We showed that the assumption of minimum phase does not reflect a suitable response in the case of mixed-phase wavelets. Application of this algorithm on synthetic and real data shows that subtle reflectivity information could be recovered and vertical seismic resolution is significantly improved. 相似文献
22.
Multiridge Euler deconvolution 总被引:1,自引:0,他引:1
Potential field interpretation can be carried out using multiscale methods. This class of methods analyses a multiscale data set, which is built by upward continuation of the original data to a number of altitudes conveniently chosen. Euler deconvolution can be cast into this multiscale environment by analysing data along ridges of potential fields, e.g., at those points along lines across scales where the field or its horizontal or vertical derivative respectively is zero. Previous work has shown that Euler equations are notably simplified along any of these ridges. Since a given anomaly may generate one or more ridges we describe in this paper how Euler deconvolution may be used to jointly invert data along all of them, so performing a multiridge Euler deconvolution. The method enjoys the stable and high‐resolution properties of multiscale methods, due to the composite upward continuation/vertical differentiation filter used. Such a physically‐based field transformation can have a positive effect on reducing both high‐wavenumber noise and interference or regional field effects. Multiridge Euler deconvolution can also be applied to the modulus of an analytic signal, gravity/magnetic gradient tensor components or Hilbert transform components. The advantages of using multiridge Euler deconvolution compared to single ridge Euler deconvolution include improved solution clustering, increased number of solutions, improvement of accuracy of the results obtainable from some types of ridges and greater ease in the selection of ridges to invert. The multiscale approach is particularly well suited to deal with non‐ideal sources. In these cases, our strategy is to find the optimal combination of upward continuation altitude range and data differentiation order, such that the field could be sensed as approximately homogeneous and then characterized by a structural index close to an integer value. This allows us to estimate depths related to the top or the centre of the structure. 相似文献
23.
柯西约束盲反褶积技术在井间地震的应用 总被引:10,自引:4,他引:6
利用地面三维地震资料将二维井间地震资料推广到井间范围以外。对于提高井间地震的效益,加快其应用十分重要.为了将井间地震二维资料推广到井外三维,需要从地面地震低频信息提取层位、断面的几何信息,反褶积方法是重要的部分.本文给出了盲源反褶积方法的一种具体实现。并结合优化的预条件共轭梯度法以改善算法的稳定性,同时减少计算量.然后对经过高频恢复的地面地震数据与井间地震数据进行联合约束反演,有效地提高了地面地震的频带.并用实际资料的处理给予证实. 相似文献
24.
本文研究塔里木盆地区域磁异常图的反演及磁源体结构.由于众多异常的叠加和反演固有的多解性,区域磁异常图的准确解释是非常困难的.三维欧拉反褶积是一种确定地质体位置和埋藏深度的自动定量反演方法,比较适用于计算区域磁异常源的埋藏深度.由于大型克拉通沉积盆地地层具有上新下老的规律性,将磁异常源分解为三个深度层次,圈定它们各自的分布区域,便可将它们与形成的地质作用及时代联系起来,为准确解释区域磁异常图提供可靠的依据.本文应用三维欧拉反褶积反演方法,计算出的塔里木盆地深度为2~5 km、5~10 km、10~20 km三个等级的磁异常源,它们与形成的地质作用及时代分别为: 中生代构造运动,海西期玄武岩侵位和太古代结晶基底的变质作用;圈定了它们各自的分布区域. 相似文献
25.
G.R.J. Cooper 《Geophysical Prospecting》2012,60(5):995-1000
The application of semi‐automatic interpretation techniques to potential field data can be of significant assistance to a geophysicist. This paper generalizes the magnetic vertical contact model tilt‐depth method to gravity data using a vertical cylinder and buried sphere models. The method computes the ratio of the vertical to the total horizontal derivative of data and then identifies circular contours within it. Given the radius of the contour and the contour value itself, the depth to the source can be determined. The method is applied both to synthetic and gravity data from South Africa. The Matlab source code can be obtained from the author upon request. 相似文献
26.
27.
地震干涉技术可以将任意2个检波器接收到的数据合成为在若干检波器之间传播的波,就好像其中的一个检波器作为一个虚拟震源来发挥作用。它可以从混沌无序的地震信号中发现有用信息,从地震噪声中提取有用信号以此推断地震波穿过介质的地质构造。基于反褶积算法,对其理论公式进行了较详细的推导,实现被动源地震干涉成像,证明了反褶积算法的可行性;并将其结果与互相关算法的结果进行对比,分析了2种方法在信噪比和分辨率方面的差异。数值计算表明,反褶积算法的纵向分辨率比互相关算法的高。对其进行的加噪试算表明,震源叠加后的反褶积算法呈现出高信噪比的特点。 相似文献
28.
Data refinement refers to the processes by which a dataset’s resolution, in particular, the spatial one, is refined, and is thus synonymous to spatial downscaling. Spatial resolution indicates measurement scale and can be seen as an index for regular data support. As a type of change of scale, data refinement is useful for many scenarios where spatial scales of existing data, desired analyses, or specific applications need to be made commensurate and refined. As spatial data are related to certain data support, they can be conceived of as support-specific realizations of random fields, suggesting that multivariate geostatistics should be explored for refining datasets from their coarser-resolution versions to the finer-resolution ones. In this paper, geostatistical methods for downscaling are described, and were implemented using GTOPO30 data and sampled Shuttle Radar Topography Mission data at a site in northwest China, with the latter’s majority grid cells used as surrogate reference data. It was found that proper structural modeling is important for achieving increased accuracy in data refinement; here, structural modeling can be done through proper decomposition of elevation fields into trends and residuals and thereafter. It was confirmed that effects of semantic differences on data refinement can be reduced through properly estimating and incorporating biases in local means. 相似文献
29.
30.