全文获取类型
收费全文 | 816篇 |
免费 | 292篇 |
国内免费 | 121篇 |
专业分类
测绘学 | 19篇 |
大气科学 | 10篇 |
地球物理 | 311篇 |
地质学 | 782篇 |
海洋学 | 38篇 |
综合类 | 38篇 |
自然地理 | 31篇 |
出版年
2024年 | 3篇 |
2023年 | 10篇 |
2022年 | 27篇 |
2021年 | 27篇 |
2020年 | 32篇 |
2019年 | 34篇 |
2018年 | 32篇 |
2017年 | 27篇 |
2016年 | 33篇 |
2015年 | 30篇 |
2014年 | 55篇 |
2013年 | 62篇 |
2012年 | 76篇 |
2011年 | 61篇 |
2010年 | 53篇 |
2009年 | 61篇 |
2008年 | 77篇 |
2007年 | 86篇 |
2006年 | 58篇 |
2005年 | 59篇 |
2004年 | 46篇 |
2003年 | 46篇 |
2002年 | 27篇 |
2001年 | 31篇 |
2000年 | 22篇 |
1999年 | 19篇 |
1998年 | 21篇 |
1997年 | 19篇 |
1996年 | 20篇 |
1995年 | 7篇 |
1994年 | 16篇 |
1993年 | 11篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1990年 | 8篇 |
1989年 | 3篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1954年 | 2篇 |
排序方式: 共有1229条查询结果,搜索用时 953 毫秒
831.
从单片机技术的应用、深度测量、测斜仪数值计算与误差校正,无缆测井资料的数据处理等几个方面,论述了深孔无缆测井系统的研究。 相似文献
832.
We suggest a method of multi-element low-frequency acoustic logging data processing which combines advantages of the semblance and phase velocity processing (PVP) techniques, namely, the interference resistance in the former and better accuracy in the latter. The new method is based on point (windowless) semblance by the Hilbert transformation. The introduced concept of phase semblance makes it possible to estimate the signal distribution semblance and the phase. Also suggested are an algorithm for preliminary estimation of formation S-wave slowness from signal group power variations and improved forms of processed data imaging. 相似文献
833.
Vladimir Cermak Jan Safanda Louise Bodri 《International Journal of Earth Sciences》2008,97(2):365-373
Temperature was monitored in two boreholes in Kamchatka (Russia) in years 2001–2003. Ten-min reading (sampling) interval was
selected for the first half-year run followed by shorter (12 days) experiment with 5-s reading interval. A similar experiment
was repeated later in the test borehole Sporilov (Prague, Czech Republic), where four temperature–time series were performed
with reading intervals varying from 1 to 20 s. All temperature–time series (except the record from the bottom of the hole)
displayed intermittent, non-periodic oscillations of temperature of up to several hundredths of degree with sharp gradients
and large fluctuations over all observed time intervals. No such oscillation was detected at the bottom of the hole. The spectral
analysis revealed a high level of stochasticity in the measured signal. Calculated spectra showed “band-pass” behavior without
any definite peaks, which might characterize certain periodicity. Local growth of the second moment technique revealed the
presence of at least two distinct temperature-forming processes. One of them can be related to heat transfer in the structurally
and compositionally complex subsurface. The second process, which presents the bulk of the measured signal, probably reflects
certain intra-hole convection. We hypothesized that the oscillatory regime of such convection is responsible for the stochastic
nature of measured temperatures. Results of numerical modeling describing the fluctuation of water-cells in a vertical slot
support the idea of thermally unstable water column in a hole, the instability of which produces a complex oscillation system.
Model solutions and their discussion is presented in Part II of this work. 相似文献
834.
835.
综合测井在滑坡勘查中的应用 总被引:1,自引:1,他引:0
吴向明 《水文地质工程地质》1998,25(1):53-55,61
综合四川省汉源县城后山的滑坡勘查工作,介绍了采用综合测井方法在确定滑坡滑面位置和滑体厚度中的应用,取得了较好的效果。 相似文献
836.
From the mathematical studies, the conservative relationships of the depth integral areas of the linear well logs and the
nonlinear well logs are derived: the depth integral area of a linear well log is not relevant to its vertical resolution,
while the depth integral area of a nonlinear well log is closely related to its vertical resolution and the higher the resolution,
the bigger the depth integral area. Then, the effects of the mathematical transformations on the above relationships are studied.
Finally, the conservative relationships of the shale volume content log and the porosity log are derived for some given conditions.
Project supported by the National Natural Science Foundation of China (Grant No. 49200-400). 相似文献
837.
838.
The influence of carbonate formation on Pulsed Neutron logging(such as Pulsed Neutron-Neutron logging)is quite different from that of sandstone due to the complexity of reservoir architecture and the development of fracture in carbonate reservoir.To study the factors affecting Pulsed Neutron-Neutron(PNN)logging in carbonate formation,the responses on fracture or cave are simulated by Monte Carlo method,getting the relationships among the macroscopic capture cross section(Σ),the count ratio of the thermal neutron at far spacing and near spacing detectors(RATIO),the fracture porosity,oil-bearing and shale content of fracture.The results show that PNN logging can be used to detect caves,and there exist linear relationships among the macroscopic capture cross section(Σ),the count ratio(RATIO)and the above factors.The research findings in this paper provides theoretical basis for the interpretation and data correction of the PNN logging in carbonate reservoirs. 相似文献
839.
CO2气藏由于其物理、化学性质的特殊性,CO2气勘探与烃类气既有相同又有区别,综合应用多种资料和多种技术方法是识别CO2气(层)藏的有效手段。利用区域地质分析、地球物理和地球化学勘探方法综合评价非烃气的分布,提出钻探目标,通过非烃色谱测量法和红外线CO2气体浓度测量法实现CO2气层钻井现场动态检测,利用气体色谱检测相关录井参数资料、核测井密度中子孔隙度差值综合解释CO2气层,有效地识别CO2气。主要介绍CO2气藏综合勘探技术的关键的新技术方法,如地球化学方法、录井和测井综合识别的关键技术方法等。 相似文献
840.
支持向量机在水淹层测井识别中的应用 总被引:2,自引:1,他引:1
支持向量机(SVM)算法是特别适合于用有限已知样本训练建模,进而预报未知样本属性的模式识别新算法。笔者尝试将Vapnik提出的支持向量机算法用于水淹层测井识别。总结了P油田水淹层的声波时差、自然电位、深感应电阻率、中感应电阻率及密度测井曲线与水淹程度的对应关系,建立了基于支持向量分类机的识别模型,并将上述参数作为训练样本的输入,油气特征作为训练样本的输出,对支持向量机进行训练。对于P油田水淹层的实际预测结果表明:支持向量机可以成为一种用于水淹层识别的有效工具。 相似文献