全文获取类型
收费全文 | 800篇 |
免费 | 129篇 |
国内免费 | 144篇 |
专业分类
测绘学 | 13篇 |
大气科学 | 4篇 |
地球物理 | 276篇 |
地质学 | 589篇 |
海洋学 | 67篇 |
天文学 | 5篇 |
综合类 | 58篇 |
自然地理 | 61篇 |
出版年
2024年 | 8篇 |
2023年 | 9篇 |
2022年 | 18篇 |
2021年 | 26篇 |
2020年 | 23篇 |
2019年 | 39篇 |
2018年 | 17篇 |
2017年 | 27篇 |
2016年 | 28篇 |
2015年 | 34篇 |
2014年 | 42篇 |
2013年 | 71篇 |
2012年 | 42篇 |
2011年 | 30篇 |
2010年 | 38篇 |
2009年 | 55篇 |
2008年 | 74篇 |
2007年 | 43篇 |
2006年 | 39篇 |
2005年 | 38篇 |
2004年 | 49篇 |
2003年 | 29篇 |
2002年 | 46篇 |
2001年 | 26篇 |
2000年 | 23篇 |
1999年 | 24篇 |
1998年 | 15篇 |
1997年 | 16篇 |
1996年 | 21篇 |
1995年 | 24篇 |
1994年 | 11篇 |
1993年 | 18篇 |
1992年 | 16篇 |
1991年 | 14篇 |
1990年 | 12篇 |
1989年 | 3篇 |
1988年 | 9篇 |
1987年 | 3篇 |
1986年 | 8篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有1073条查询结果,搜索用时 15 毫秒
51.
Two major faults, over 32 km long and 6.4 km apart, truncate or overprint most previous folds and faults as they trend more northerly than the previous N25°E to N40°E fold trends. The faults were imposed as the last event in a region undergoing sequential counter-clockwise generation of tectonic structures. The western Big Cove anticline has an early NW verging thrust fault that emplaces resistant rocks on its NW limb. A 16 km overprint by the Cove Fault is manifested as 30 small northeast striking right-lateral strike-slip faults. This suggests major left-lateral strike-slip separation on the Cove Fault, but steep, dip-slip separation also occurs. From south to north the Cove Fault passes from SE dipping beds within the Big Cove anticline, to the vertical beds of the NW limb. Then it crosses four extended, separated, Tuscarora blocks along the ridge, brings Cambro-Ordovician carbonates against Devonian beds, and initiates the zone of overprinted right-lateral faults. Finally, it deflects the Lat 40°N fault zone as it crosses to the next major anticline to the northwest. To the east, the major Path Valley Fault rotates and overprints the earlier Carrick Valley thrust. The Path Valley Fault and Cove Fault may be Mesozoic in age, based upon fault fabrics and overprinting on the east–west Lat 40°N faults. 相似文献
52.
We report for the first time the occurrence of polygonal faults in sandstone, which is compelling given that layer-bound polygonal fault systems have been observed so far only in fine-grained sediments such as clay and chalk. The polygonal faults are shear deformation bands that developed under shallow burial conditions via strain hardening in dm-wide zones. The edges of the polygons are 1–5 m long. The shear deformation bands are organized as conjugate faults along each edge of the polygon and form characteristic horst-like structures. The individual deformation bands have slip magnitudes ranging from a few mm to 1.5 cm; the cumulative average slip magnitude in a zone is up to 10 cm. The deformation bands heaves, in aggregate form, accommodate a small isotropic horizontal extension (strain <0.005). The individual shear deformation bands show abutting T-junctions, veering, curving, and merging where they mechanically interact. Crosscutting relationships are rare. The interactions of the deformation bands are similar to those of mode I opening fractures. The documented fault networks have important implications for evaluating the geometry of km-scale polygonal fault systems in the subsurface, top seal integrity, as well as constraining paleo-tectonic stress regimes. 相似文献
53.
Q. H. Liu Y. Shu X. M. Zhu X. H. Yang M. Tan 《Australian Journal of Earth Sciences》2016,63(7):903-922
The effects of low- to high-angle (>30°) normal faults on sedimentary architectural units in the Eocene Wenchang Formation, Enping Sag, Pearl River Mouth Basin (PRMB), South China Sea were investigated utilising a high-quality 3D seismic data set and restored paleogeomorphology. It has been shown that sequence stratigraphic units and sedimentary architecture are significantly controlled by the low- to high-angle normal faults. The Wenchang Formation, a second-order sequence, can be subdivided into two para-second-sequences (the Lower and Upper Wenchang sequences, E2WL and E2WU) and seven third-order sequences (from base to top: SQ1~SQ7). The low-angle fault confined sequence architecture of the Wenchang Formation is mainly characterised by lateral stacking with the ratio of the vertical subsidence (V) to horizontal slip (H) being reduced from 1/2 for E2WL to 1/6 for E2WU. In contrast, the high-angle fault confined sequence is characterised by vertical stacking with the ratio of V/H close to 1 for sequences SQ1 to SQ7. In the 3D seismic area, the features of sediment-dispersal pattern were interpreted based on an integrated analysis of paleogeomorphology, seismic reflection characteristics, stratal thickness distribution and multiple attribute clustering. The results show that the large-scale fan delta, belt-shape lacustrine deposit and bird-foot braided delta systems mainly developed in the low-angle fault confined sequences, whereas small-scale fan delta, rhombus-shaped lacustrine deposit and lobe-shaped braided delta systems inherited tectono-sedimentary architectures in the high-angle fault confined sequences. 相似文献
54.
在隐蔽油气藏勘探中,正确刻画储层断裂对于油气勘探和开发都有着至关重要的作用.储层断裂在地震数据中表现为边缘特征.但现今多尺度边缘检测的基本理论和方法都有其本身的局限性.本文详细阐述了Steerable Pyramid分解用于储层断裂检测的基本原理和方法.输入的三维地震切片经过Steerable Pyramid分解后,不仅可以分析不同尺度不同方向上断裂的特征及走向,还可以通过重构得到经S函数控制的断裂信息,该断裂信息不仅仅是断裂的边缘检测,而是增强的断裂本身.将该算法应用于实际地震切片的断裂检测,得到了清晰的断裂信息,完整细致地展现了这些地质类型的特征,为构造解释、地震相表征及储层预测提供了有用信息. 相似文献
55.
56.
Normal fault growth and linkage in the Gediz (Alaşehir) Graben,Western Turkey,revealed by transient river long‐profiles and slope‐break knickpoints 下载免费PDF全文
Emiko Kent Sarah J. Boulton Alexander C. Whittaker Iain S. Stewart M. Cihat Alçiçek 《地球表面变化过程与地形》2017,42(5):836-852
The Gediz (Ala?ehir) Graben is located in the highly tectonically active and seismogenic region of Western Turkey. The rivers upstream of the normal fault‐bounded graben each contain a non‐lithologic knickpoint, including those that drain through inferred fault segment boundaries. Knickpoint heights measured vertically from the fault scale with footwall relief and documented fault throw (vertical displacement). Consequently, we deduce these knickpoints were initiated by an increase in slip rate on the basin‐bounding fault, driven by linkage of the three main fault segments of the high‐angle graben bounding fault array. Fault interaction theory and ratios of channel steepness suggest that the slip rate enhancement factor on linkage was a factor of 3. We combine this information with geomorphic and structural constraints to estimate that linkage took place between 0.6 Ma and 1 Ma. Calculated pre‐ and post‐linkage throw rates are 0.6 and 2 mm/yr respectively. Maximum knickpoint retreat rates upstream of the faults range from 4.5 to 28 mm/yr, faster than for similar catchments upstream of normal faults in the Central Apennines and the Hatay Graben of Turkey, and implying a fluvial landscape response time of 1.6 to 2.7 Myr. We explore the relative controls of drainage area and precipitation on these retreat rates, and conclude that while climate variation and fault throw rate partially explain the variations seen, lithology remains a potentially important but poorly characterised variable. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
57.
《International Geology Review》2012,54(4):468-481
The Neogene–Quaternary Siderno Basin is located in the southern Calabrian Arc, along an E–W transect including the Ionian side and part of the Tyrrhenian margin. The orogenic belt was generated by ongoing northward subduction of Ionian oceanic lithosphere beginning in the Early Cretaceous. Since the Oligocene, the area has experienced complex tectonics, including NW–SE-oriented pull-apart basins. The forearc region contains >2000 m of Oligocene-to-Quaternary strata that cover pre-Tertiary rocks. The succession forms an E-dipping monocline, with tectonic growth structures increasing upward. Erosional truncations and thickness variations suggest a different evolution for the Siderno Basin, which in comparison with northern and southern parts of the Ionian accretionary wedge, evolved differently during the Serravallian–Tortonian stages. NW–SE and NE–SW fault systems are dominant, the first exhibiting strike–slip and normal kinematics in the Nicotera–Gioiosa and Molochio–Antonimina fault zones. These structures were active during infilling of the Neogene basin, and represent a complex transfer zone. The NE–SW system shows two types of tectonic kinematics: (1) a compressive stage, with NW–SE-orientated shortening, responsible for inversion tectonics documented by east-verging folds, thrusts, and back-thrusts, and (2) emplacement of the variegated clay during the Langhian, which is related to back-thrust propagation. The strike–slip accommodated stress generated in the accretionary prism in response to subduction of Ionian lithosphere and progradation of the accretionary front of the Calabrian forearc. 相似文献
58.
59.
三叠纪嘉陵江期华蓥山同沉积断层的沉积、储层响应 总被引:1,自引:0,他引:1
对于断裂带在地质历史时期活动特点的认识,因多期次、不同活动性质的叠加改造而难以确定。以四川盆地南部嘉陵江组为例,通过三叠纪嘉陵江期华蓥山断裂带两侧的沉积、储层的研究发现沉积、储层响应与断面倾向南东、东侧下降的观点矛盾。主要表现为:在非浅滩化的嘉三期,紧邻断裂带西北侧的下降盘地层异常增厚;浅滩化的嘉一晚期—嘉二1期,东南侧的泸州古隆起地区颗粒岩累计厚度较西北侧增厚;另外,断层东南侧的颗粒岩发育早期岩溶型储层,而在西北侧这类储层欠发育。结果表明在三叠纪嘉陵江期华蓥山断裂带的断面倾向北西,为西侧下降的同沉积正断层。 相似文献
60.