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排序方式: 共有88条查询结果,搜索用时 15 毫秒
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多波多分量地震勘探方法在油气田勘探开发中日益受到重视,但在工程和活动断裂探测中过去还没有开展多波多分量地震勘探的先例.本文简要介绍了在北京黄庄—高丽营断裂上开展的三分量浅层地震反射试验数据采集和资料处理方法,以及取得的初步结果.试验结果表明,采用纵波震源或横波震源激发、三分量接收的浅层地震勘探方法,可获得较高信噪比的浅层地震纵波、横波和转换波剖面,特别是水平分量采集的横波和转换波可提供很有意义的地下结构和构造信息.综合利用纵波、横波和转换波剖面特征进行的地质分层和断层解释结果取得了与跨断层的钻孔联合地质剖面结果较好的一致性. 相似文献
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由于小波变换特殊的性质决定了其在GPS监测数据中的应用,它能够提高GPS的定位精度和速度,并且在周跳检测、波形分解、消除噪声、数据压缩等方面大有可为。 相似文献
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本文提出了一种基于模型空间压缩技术的大地电磁三维反演方法.该方法在传统大地电磁三维反演理论的基础上,通过小波变换将待反演的空间域模型参数映射到小波域进行反演,获得小波域更新模型后再通过小波逆变换得到空间域反演模型.由于小波变换具有压缩特性和多尺度分辨能力,本文反演方法可在一定程度上提高反演分辨率.为了提高反演效率,我们针对基于L1范数的模型约束求解不易收敛的反演问题,提出了一种基于模型粗糙度的简单有效的预条件处理技术.为验证本文算法的有效性,本文首先对经典的"棋盘"模型进行三维反演测试.反演结果表明本文算法的反演效率与传统方法相当,但对于深部异常体具有更好的分辨能力.最后,我们通过对实测数据反演进一步验证本文算法的有效性. 相似文献
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Michael S.J. Mlynarczyk Anthony E. Williams-Jones 《Earth and Planetary Science Letters》2005,240(3-4):656-667
The Inner Arc of the Central Andes, broadly corresponding to the Eastern Cordillera, is the location of a rich Tertiary and Triassic Sn–W–(Ag-base metal) metallogenic province, commonly referred to as the Bolivian tin belt. We propose that the Tertiary metallogeny, which generated most of the tin ores, was a direct consequence of discrete “collisions” between the South American plate and the Nazca slab and sub-slab mantle, during the ongoing Andean orogeny. Evidence supporting this proposal include: (1) the coincidence of the tin province and the Inner Arc in a marked “hump” in the Andean orogen, which may represent tectonic indentation; (2) the symmetry of the tin province with respect to the Bolivian orocline, the axis of which corresponds to the direction of highest compression; (3) the relative symmetry of the magmatism and tin mineralization with respect to this axis; (4) the concurrent timing of mineralization and compressional pulses; (5) the similar host rock geochemistry and ore lead isotope data, testifying to a common crustal reservoir; and (6) the striking similarity of the igneous suites, associated with the ore deposits to those from “typical” collisional orogens. A number of studies have called upon a persistent tin anomaly to explain the metallogeny of the region. We propose, instead, that the latter is better explained by periodic compressional interaction between the Farallon/Nazca oceanic plate and the South American continent. This led to the generation of peraluminous magmas, which during fractional crystallization exsolved the fluids responsible for the voluminous Sn–W mineralization. 相似文献
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鄂尔多斯块体西缘及西南缘深部电性结构与该区地质构造的关系 总被引:6,自引:0,他引:6
对在地理位置上具有一定代表性的鄂尔多斯块体西缘及西南缘的3 条大地电磁剖面进行了分析。盐池—阿拉善左旗剖面:整条剖面上均有壳内低阻层和上地幔低阻层分布,低阻层在银川断陷盆地上隆。定边—景泰剖面:壳内低阻层仅出现在弧形断裂带区,但上地幔低阻层在整个剖面上都有分布。在弧形断裂带区上地幔低阻层埋藏深度加大,但并不上隆,这与北面银川断陷盆地的上地幔上隆形成反照。分析认为,银川断陷盆地属于拉张性质,而弧形断裂带区属于挤压性质,由于均衡调整作用,造成了两者上地幔结构的反差。成县—西吉剖面:以天水太京测点为界,其南、北两段的电性结构差异较大,这为划分南、北两个地质单元提供了深部结构上的依据 相似文献
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Tariq Alkhalifah 《Geophysical Prospecting》2011,59(1):1-9
Kirchhoff 3D prestack migration, as part of its execution, usually requires repeated access to a large traveltime table data base. Access to this data base implies either a memory intensive or I/O bounded solution to the storage problem. Proper compression of the traveltime table allows efficient 3D prestack migration without relying on the usually slow access to the computer hard drive. Such compression also allows for faster access to desirable parts of the traveltime table. Compression is applied to the traveltime field for each source location on the surface on a regular grid using 3D Chebyshev polynomial or cosine transforms of the traveltime field represented in the spherical coordinates or the Celerity domain. We obtain practical compression levels up to and exceeding 20 to 1. In fact, because of the smaller size traveltime table, we obtain exceptional traveltime extraction speed during migration that exceeds conventional methods. Additional features of the compression include better interpolation of traveltime tables and more stable estimates of amplitudes from traveltime curvatures. Further compression is achieved using bit encoding, by representing compression parameters values with fewer bits. 相似文献
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We have developed a generalized quantitative technique for determining the finite pole of rotation between two rigid plates and use it to critically examine differing reconstructions of a region surrounding a prominent dark spot on Europa, Castalia Macula. This region is located near the equator of Europa's trailing hemisphere and has been suggested as a site where crustal convergence may have occurred. Previous reconstructions of the region have indicated that a ridge set and/or a band-like complex that define a collection of tectonic plates in the region accommodated surface contraction. However, a critical examination of the differences between these reconstructions has been complicated by the lack of a finite pole of rotation for the plates involved in either reconstruction. We have applied our modeling technique, coupled with a detailed examination of the morphology and cross-cutting relationships involving this ridge set and band-like complex, to determine if a unique reconstruction exists for several tectonic plates in this region. The cross-cutting relationships involving the ridge set also allow us to test the general assumption that plates behave rigidly on Europa. Assuming rigid behavior, our results suggest that a unique reconstruction does exist, indicating the ridge set accommodated surface contraction. However, analysis performed to test the assumption of plate rigidity indicates that one or more of the plates in the region did not behave rigidly. This does not rule out surface contraction along the ridge set but does indicate that a component of nonrigid behavior must be considered. 相似文献