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61.
裂缝问题是火山岩复杂岩性油气藏勘探开发中必须考虑的重要因素之一.火山岩储层裂缝预测的准确性直接影响着油气的产能、钻井工艺和增产改造措施等.本文主要根据等效HTI介质(扩容各向异性介质)的特性,立足地下介质各向异性理论,利用三维地震叠前P波在HTI介质中的属性分布特征来检测裂缝的发育情况.利用三维地震叠前P波裂缝检测技术在松辽盆地北部徐家围子断陷深层营城组火山岩中尝试开展了储层裂缝发育预测研究.通过研究建立了火山岩裂缝地震叠前预测方法,并对营城组火山岩裂缝发育情况进行预测,结果表明裂缝主要分布在工区中部构造高部位,发育方向以北北西向为主.最后利用测井资料和钻井产能资料等进行效果分析,证实该技术对于认识火山岩储层裂缝发育具有实际应用价值,说明应用地震资料开展储层裂缝预测具有横向分辨率高、实现井间分布描述和宏观空间分布规律清楚等特点. 相似文献
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利用地震数据反演海水的温盐分布是地震海洋学研究的一个重要方向.本文分析了采集于伊比利亚半岛西南缘海域的GOLR12低频地震数据和同步观测的XBT(eXpendable BathyThermograph)、CTD(Conductivity-Temperature-Depth)资料,将叠后约束波阻抗反演方法应用到海水温度、盐度剖面的计算当中,计算结果显示这种反演方法可以提供水平分辨率为6.25 m的温度和盐度资料,温度的精度约为0.16 ℃,可以为物理海洋学研究提供高横向分辨率的基础数据. 相似文献
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Roman Pevzner Valeriya Shulakova Anton Kepic Milovan Urosevic 《Geophysical Prospecting》2011,59(1):66-77
Time‐lapse seismics is the methodology of choice for remotely monitoring changes in oil/gas reservoir depletion, reservoir stimulation or CO2 sequestration, due to good sensitivity and resolving power at depths up to several kilometres. This method is now routinely applied offshore, however, the use of time‐lapse methodology onshore is relatively rare. The main reason for this is the relatively high cost of commercial seismic acquisition on land. A widespread belief of a relatively poor repeatability of land seismic data prevents rapid growth in the number of land time‐lapse surveys. Considering that CO2 sequestration on land is becoming a necessity, there is a great need to evaluate the feasibility of time‐lapse seismics for monitoring. Therefore, an understanding of the factors influencing repeatability of land seismics and evaluating limitations of the method is crucially important for its application in many CO2 sequestration projects. We analyse several repeated 2D and 3D surveys acquired within the Otway CO2 sequestration pilot project (operated by the Cooperative Research Centre for Greenhouse Technologies, CO2CRC) in Australia, in order to determine the principal limitations of land time‐lapse seismic repeatability and investigate the influence of the main factors affecting it. Our findings are that the intrinsic signal‐to‐noise ratio (S/N, signal to coherent and background noise levels) and the normalized‐root‐mean‐square (NRMS) difference are controlled by the source strength and source type. However, the post‐stack S/N ratio and corresponding NRMS residuals are controlled mainly by the data fold. For very high‐fold data, the source strength and source type are less critical. 相似文献
67.
Roberto de Franco 《Geophysical Prospecting》2011,59(3):432-454
This paper presents a signal processing procedure to perform refractor velocity analysis. The procedure enables one to obtain the seismic velocity from the refracted wavefield without the picking of refracted arrival times. Two processing procedures are derived, one starting from a seismic interferometric approach and another, from the conventional reciprocal method and generalized reciprocal method approaches. The theoretical equivalence of the two approaches is also demonstrated. The proposed processing procedure is applied to synthetic data in order to test the influence of some procedural parameters and its capability to reconstruct a known velocity model starting from refracted signals, without and with perturbations, in arrival times and noise; finally, it is applied to a field data set. 相似文献
68.
Flavio Poletto Lorenzo Petronio Biancamaria Farina Andrea Schleifer 《Geophysical Prospecting》2011,59(3):464-476
We present the results of a seismic interferometry experiment in a shallow cased borehole. The experiment is an initial study for subsequent borehole seismic surveys in an instrumented well site, where we plan to test other surface/borehole seismic techniques. The purpose of this application is to improve the knowledge of the reflectivity sequence and to verify the potential of the seismic interferometry approach to retrieve high‐frequency signals in the single well geometry, overcoming the loss and attenuation effects introduced by the overburden. We used a walkaway vertical seismic profile (VSP) geometry with a seismic vibrator to generate polarized vertical and horizontal components along a surface seismic line and an array of 3C geophones cemented outside the casing. The recorded traces are processed to obtain virtual sources in the borehole and to simulate single‐well gathers with a variable source‐receiver offset in the vertical array. We compare the results obtained by processing the field data with synthetic signals calculated by numerical simulation and analyse the signal bandwidth and amplitude versus offset to evaluate near‐field effects in the virtual signals. The application provides direct and reflected signals with improved bandwidth after vibrator signal deconvolution. Clear reflections are detected in the virtual seismic sections in agreement with the geology and other surface and borehole seismic data recorded with conventional seismic exploration techniques. 相似文献
69.
Spatial sensitivity of seismic hazard results to different models with respect to background seismic activity and earthquake occurrence in time is investigated. For the contribution of background seismic activity to seismic hazard, background area source with uniform seismicity and spatially smoothed seismicity models are taken into consideration. For the contribution of faults, through characteristic earthquakes, both the memoryless Poisson and the time dependent renewal models are utilized. A case study, involving the assessment of seismic hazard for the Bursa province in Turkey, is conducted in order to examine quantitatively the influence of these models on seismic hazard results. The spatial variation of the difference in Peak Ground Acceleration (PGA) values obtained from these different models is presented in the form of difference maps for return periods of 475 and 2475 years. Best estimate seismic hazard maps for PGA and Spectral Accelerations (SA) at 0.2 and 1.0 s are obtained by using the logic tree method. 相似文献
70.
By using the finite element method and viscoelastic artificial boundary,a soil-structure interaction system is established to simulate the influence of surface buildings on the seismic response of subway structures.The conditions of different relative positions between ground building and subway structure are analyzed.The results indicate that when considering the existence of surface buildings,the relative story displacements and internal forces of subway structures are changed greatly.Further the influence of surface buildings on subway structure changes as the distance increases. 相似文献