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321.
山东刚玉及蓝宝石中天然包裹体的形态与分布特征研究 总被引:3,自引:0,他引:3
山东刚玉及蓝宝石中含有大量晶体包裹体和两相、三相包裹体,并沿特定面网和裂理面分布。单个晶体内的显微包裹体数以亿万计,其中两相和三相包裹体的形态十分复杂。 相似文献
322.
d:\PDF\.pdf地震共中心点道集的瞬时基准面静校正和动校正 总被引:2,自引:2,他引:2
对地震野外共炮点记录进行浮动基准面静校正后的每一个共中心点道集记录而言,其基准面仍是一局部曲面,如何使之动校正后达到同相迭加,必须作所谓瞬时基准面静、动校正处理。本文从理论上阐述了共中心道集记录的瞬时基准面静、动校正的方法和技术,并用理论模型试算验证了该方法能够消除由于局部起伏对共中心点道集记录的影响,提高时间剖面的质量、速度和解释精度,确保在山区中采用地震反射波法多次覆盖技术勘探的成功。 相似文献
323.
大型滑坡滑带土结构强度再生特征及其机理探讨 总被引:9,自引:1,他引:9
大型滑坡滑带土强度参数的正确选取,是作好滑坡稳定性评价和抗滑工程设计的重要环节。本文在现场调研和室内试验基础上,揭示了只要具有一定滑体厚度的滑带土,沿滑面具有强度再生现象,尤其在抗剪强度参数中显著存在一定量值的结构强度。讨论了结构强度再生的条件、变化规律及其再生机理,论证了滑带土的残余强度仅仅是一种瞬时效应,为滑坡滑面强度参数的选取与评价提供了重要的理论依据。 相似文献
324.
本文通过应用浅震反射波法解决浅部滑坡体、孤石、基桩持力层等特殊工程地质问题,阐明浅震反射波法在工程勘察中具有良好的应用效果及应用前景。 相似文献
325.
峨眉山玄武岩母岩浆的性质及其成因类型 总被引:3,自引:1,他引:3
作者通过对峨眉山玄武岩的研究工作,对峨眉山玄岩浆提出新的看法,认为它是一种过渡类型的临界面岩浆。 相似文献
326.
本文从理论上论述了复杂地形条件下常规基准面静校正和存在的误差以及存在误差的主要原因。提出了一种新野外静校正方法──浮动基准面静校正,完全消除了常规基准面静校正方法所存在的误差,提高了地震时间剖面的质量和解释精度。 相似文献
327.
Jan Moeyersons 《地球表面变化过程与地形》1988,13(6):511-524
Long term soil creep motion is often represented as a type of laminar flow, with velocity vectors parallel to the slope and constant in time. Records on a hillslope in Southern Rwanda reveal that creep movements there compare more with turbulent flow, characterized by a A1 humic horizon superlayer, creeping over a subsoil affected by more irregular creep deformation. 相似文献
328.
B. Papazachos A. Kiratzi B. Karacostas D. Panagiotopoulos E. Scordilis D. M. Mountrakis 《Pure and Applied Geophysics》1988,126(1):55-68
A shallow earthquake ofM
S=6.2 occurred in the southern part of the Peloponnesus, 12 km north of the port of the city of Kalamata, which caused considerable damage. The fault plane solution of the main shock, geological data and field observations, as well as the distribution of foci of aftershocks, indicate that the seismic fault is a listric normal one trending NNE-SSW and dipping to WNW. The surface ruptures caused by the earthquake coincide with the trace of a neotectonic fault, which is located 2–3 km east of the city of Kalamata and which is related to the formation of Messiniakos gulf during the Pliocene-Quaternary tectonics. Field observations indicate that the earthquake is due to the reactivation of the same fault.A three-days aftershock study in the area, with portable seismographs, recorded many aftershocks of which 39 withM
S1.7 were very well located. The distribution of aftershocks forms two clusters, one near the epicenter of the main shock in the northern part of the seismogenic volume, and the other near the epicenter of the largest aftershock (M
S=5.4) in the southern part of this volume. The central part of the area lacks aftershocks, which probably indicates that this is the part of the fault which slipped smoothly during the earthquake. 相似文献
329.
攀西裂谷带及其邻区的现代构造应力场特征 总被引:1,自引:0,他引:1
本文主要根据近30多年来,发生在攀西裂谷地区地震的断层面解,辅以其它手段的资料,讨论该地区的现代构造应力场。结果表明,攀西裂谷带的受力状态已由过去的拉张变为现今的压扭,是一条消亡的古裂谷带。 相似文献
330.
In the Solomon Islands and New Britain subduction zones, the largest earthquakes commonly occur as pairs with small separation in time, space and magnitude. This doublet behavior has been attributed to a pattern of fault plane heterogeneity consisting of closely spaced asperities such that the failure of one asperity triggers slip in adjacent asperities. We analyzed body waves of the January 31, 1974,M
w
=7.3, February 1, 1974,M
w
=7.4, July 20, 1975 (1437)M
w
=7.6 and July 20, 1975 (1945),M
w
=7.3 doublet events using an iterative, multiple station inversion technique to determine the spatio-temporal distribution of seismic moment release associated with these events. Although the 1974 doublet has smaller body wave moments than the 1975 events, their source histories are more complicated, lasting over 40 seconds and consisting of several subevents located near the epicentral regions. The second 1975 event is well modeled by a simple point source initiating at a depth of 15 km and rupturing an approximate 20 km region about the epicenter. The source history of the first 1975 event reveals a westerly propagating rupture, extending about 50 km from its hypocenter at a depth of 25 km. The asperities of the 1975 events are of comparable size and do not overlap one another, consistent with the asperity triggering hypothesis. The relatively large source areas and small seismic moments of the 1974 doublet events indicate failure of weaker portions of the fault plane in their epicentral regions. Variations in the roughness of the bathymetry of the subducting plate, accompanying subduction of the Woodlark Rise, may be responsible for changes in the mechanical properties of the plate interface.To understand how variations in fault plane coupling and strength affect the interplate seismicity pattern, we relocated 85 underthrusting earthquakes in the northern Solomon Islands Are since 1964. Relatively few smaller magnitude underthrusting events overlap the Solomon Islands doublet asperity regions, where fault coupling and strength are inferred to be the greatest. However, these asperity regions have been the sites of several previous earthquakes withM
s
7.0. The source regions of the 1974 doublet events, which we infer to be mechanically weak, contain many smaller magnitude events but have not generated any otherM
s
7.0 earthquakes in the historic past. The central portion of the northern Solomon Islands Arc between the two largest doublet events in 1971 (studied in detail bySchwartz
et al., 1989a) and 1975 contains the greatest number of smaller magnitude underthrusting earthquakes. The location of this small region sandwiched between two strongly coupled portions of the plate interface suggest that it may be the site of the next large northern Solomon Islands earthquake. However, this region has experienced no known earthquakes withM
s
7.0 and may represent a relatively aseismic portion of the subduction zone. 相似文献