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101.
102.
卢万年 《地球科学与环境学报》1987,(4)
本文提出了一种对均质土坡自重应力场的近似解析解法,并以此进行了近似计算,在此基础上,还对此进行了较详尽的分析,这对研究土坡的破裂和滑动规律具有一定的理论和实际意义。 相似文献
103.
梁建文 《地震工程与工程振动(英文版)》2003,2(2):181-187
As one of the most important urban lifeline systems, a water distribution system can be damaged under a strong earthquake, and the damage cannot easily be located, especially immediately after the event. This often causes tremendous difficulties to post-earthquake emergency response and recovery activities. This paper proposes a methodology to locate seismic damage to a water distribution system by monitoring watcr head online at some nodes in the water distribution system. An artificial neural network-based inverse analysis method is developed to estimate the water head variations at all nodes that are not monitored based on the water head variations at the nodes that are monitored. The methodology provides a quick, effective, and practical way to locate seismic damage to a water distribution system. 相似文献
104.
本文基于构造层序分析和基准面分析原理,利用测井曲线,岩相等资料,重点研究了东营凹陷沙三段3个层序的低位域砂体沉积特征,发育规律及其石油地质意义。应用构造坡折带的概念在该凹陷划分出了4种构造坡折带样式。研究表明:该凹陷沙三段层序低位域砂体发育下切水道充填,低位楔和低位扇。构造坡折带的发育特征和样式控制了低位域砂体的时空展布特征。构造坡折带控制下的低位域砂体发育在层序底部,构造坡折带附近,成藏条件优良,是隐蔽油气藏勘探的主要方向。 相似文献
105.
Binsong Zheng Renjie Zhou Xiuping Wang Zhaohui Xiao Yao Chen 《International Geology Review》2020,62(10):1262-1272
ABSTRACT The intraplate Kwangsian Orogeny is a key orogenic event in South China in the mid-Paleozoic. We re-examined the evidence for the Yichang Uplift, an inferred geographic feature during the Kwangsian Orogeny, to evaluate its timing and nature. Field, sedimentological, mineralogical and geochronological data were collected from the Late Ordovician-Early Silurian Xiaohe section, Hunan-Hubei area. Results suggest that the Xiaohe section is composed of the Late Ordovician Wufeng Formation black shale in the lower part and the Early Silurian Longmaxi Formation black shale in the upper part. We found that the clay layers interbedded in the Wufeng Formation are altered rhyolitic tuffs instead of parts of a subaerial wreathing crust. LA-ICP-MS U-Pb dating of zircons in the top tuff layer of the Wufeng Formation yielded an age of 447.0 + 1.4/- 2.2 Ma, consistent with biostratigraphic data, providing a radiometric constraint for the sedimentary break existed between the Wufeng and Longmaxi formations and confirming the absence of the Hirnantian (latest Ordovician) Guanyinqiao Formation in the study area. Our data support that the Yichang Uplift was a submarine highland possibly initiated by the reactivation of the inherited Jianshi-Enshi Fault in the Hunan-Hubei area during the Kwangsian Orogeny. 相似文献
106.
用盈亏平衡法建立最小经济储量规模模型 总被引:1,自引:0,他引:1
介绍了确定最小经济储量规模的理论依据、影响最小经济储量规模的主要因素和计算最小经济储量规模的经济要素,并用盈亏平衡原理建立了最小经济储量规模模型,计算了松辽盆地十屋断陷常规油藏在不同油价、不同埋藏深度条件下的最小经济储量规模。 相似文献
107.
108.
Fulu Men 《地震工程与工程振动(英文版)》2002,1(2):281-291
In this paper, mantle circulation flow, continental drift, earthquake origin and other mechanical principles are examined
as they apply to earthquake engineering, seismology and dynamics of fluid saturated porous medium. The relationship of mantle
flow to earthquakes is examined and clarified, and a new model, different from Haskell’s, is proposed for the earthquake mechanism.
The proposed new model is based on the discovery that two pairs of jump stress and jump velocity will start to act from the
fault plane. Records obtained directly from recent earthquakes nearby and right on the fault break show a very large velocity
impulse, which verify, indirectly, the new mechanism proposed by the author. Further, at least two physical parameters that
characterize the seismic intensity must be specified, because according to the discontinuous (jump) wave theory, at the earthquake
source, the stress jump and the velocity jump of particle motion should act simultaneously when a sudden break occurs. The
third key parameter is shown to be the break (fracture) propagation speed together with the break plane area. This parameter
influences the form of the unloading time function at the source. The maximum seismic stress in and displacement of a building
are estimated for two unfavorable combinations of the building and its base ground in terms of their relative rigidity. Finally,
it is shown that Biot’s theory of wave propagation in fluid saturated porous media is valid only when fluid flow cannot occur. 相似文献
109.
Quantifying velocity and turbulence structure in depositing sustained turbidity currents across breaks in slope 总被引:2,自引:0,他引:2
Two-dimensional experiments investigating sediment transport and turbulence structure in sustained turbidity currents that cross breaks in slope are presented as analogue illustrations for natural flows. The results suggest that in natural flows, turbulence generation at slope breaks may account for increased sand transport into basins and that the formation of a hydraulic jump may not be necessary to explain features such as the occurrence of submarine plunge pools and the deposition of coarser-grained beds in the bottomsets of Gilbert-type fan deltas. Experimental flows were generated on 0°, 3°, 6° and 9° slopes of equal length which terminated abruptly on a horizontal bed. Two-component velocities were measured on the slope, at the slope break and downstream of the slope break. Flows were depositional and non-uniform, visibly slowing and thickening with distance downstream. One-dimensional continuous wavelet transforms of velocity time series were used to produce time-period variance maps. Peaks in variance were tested against a background red-noise spectrum at the 95% level; a significant period banding occurs in the cross-wavelet transform at the slope break, attributed to increased formation of coherent flow structures (Kelvin–Helmholtz billows). Variance becomes distributed at progressively longer periods and the shape of the bed-normal-velocity spectral energy distribution changes with distance downstream. This is attributed to a shift towards larger turbulent structures caused by wake stretching. Mean velocity, Reynolds shear stress and turbulent kinetic energy profiles illustrate the mean distribution of turbulence through the currents. A turbulent kinetic energy transfer balance shows that flow non-uniformity arises through the transfer of mean streamwise slowing to mean bed-normal motion through the action of Reynolds normal stresses. Net turbulence production through the action of normal stresses is achieved on steeper slopes as turbulence dissipation due to mean bed-normal motion is limited. At the slope break, an imbalance between the production and dissipation of turbulence occurs because of the contrasting nature of the wall and free-shear boundaries at the bottom and top of the flows, respectively. A rapid reduction in mean streamwise velocity predominately affects the base of the flows and steeper proximal slope flows have to slow more at the break in slope. The increased turbulent kinetic energy, limited bed-normal motion and strong mixing imposed by steep proximal slopes means rapid slowing enhances turbulence production at the break in slope by focusing energy into coherent flow structures at a characteristic period. Thus, mean streamwise slowing is transferred into turbulence production at the slope break that causes increased transport of sediment and a decrease in deposit mass downstream of the slope break. The internal effects of flow non-uniformity therefore can be separated from the external influence of the slope break. 相似文献
110.