全文获取类型
收费全文 | 123篇 |
免费 | 3篇 |
国内免费 | 2篇 |
专业分类
测绘学 | 4篇 |
大气科学 | 17篇 |
地球物理 | 25篇 |
地质学 | 46篇 |
海洋学 | 5篇 |
天文学 | 26篇 |
自然地理 | 5篇 |
出版年
2021年 | 5篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 2篇 |
2013年 | 7篇 |
2012年 | 1篇 |
2011年 | 4篇 |
2010年 | 4篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 5篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1994年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1988年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1960年 | 1篇 |
1957年 | 1篇 |
1955年 | 1篇 |
1949年 | 1篇 |
1927年 | 1篇 |
1914年 | 1篇 |
1913年 | 1篇 |
排序方式: 共有128条查询结果,搜索用时 437 毫秒
81.
David Walsh Peter Turner Elliot Grunewald Hong Zhang James J. Butler Jr. Ed Reboulet Steve Knobbe Tom Christy John W. Lane Jr. Carole D. Johnson Tim Munday Andrew Fitzpatrick 《Ground water》2013,51(6):914-926
A small‐diameter nuclear magnetic resonance (NMR) logging tool has been developed and field tested at various sites in the United States and Australia. A novel design approach has produced relatively inexpensive, small‐diameter probes that can be run in open or PVC‐cased boreholes as small as 2 inches in diameter. The complete system, including surface electronics and various downhole probes, has been successfully tested in small‐diameter monitoring wells in a range of hydrogeological settings. A variant of the probe that can be deployed by a direct‐push machine has also been developed and tested in the field. The new NMR logging tool provides reliable, direct, and high‐resolution information that is of importance for groundwater studies. Specifically, the technology provides direct measurement of total water content (total porosity in the saturated zone or moisture content in the unsaturated zone), and estimates of relative pore‐size distribution (bound vs. mobile water content) and hydraulic conductivity. The NMR measurements show good agreement with ancillary data from lithologic logs, geophysical logs, and hydrogeologic measurements, and provide valuable information for groundwater investigations. 相似文献
82.
Residual displacement, as a significant measure of structural inelasticity, is effectively used in post-earthquake seismic assessment of structures. This demand can be considered for seismic evaluation of structures under multiple earthquakes. This study introduces a simple and novel index to predict the residual displacement of mainshock-damaged structures against subsequent aftershock. The proposed index is defined as a ratio between residual displacement of damaged structures against aftershock and peak inelastic displacement of intact structures under mainshock. In this study, constantstrength spectra based on the index are developed considering the effects of important structural characteristics and also significant seismic parameters. Moreover, analytical equations are presented to predict the proposed index for bi-linear single-degree-of-freedom(SDOF) systems considering both the effects of positive and negative polarities of aftershock. Furthermore, an equation is suggested to estimate the peak inelastic displacement of intact systems under mainshock, which is required to compute the index. 相似文献
83.
84.
Bengt Edĺen 《Solar physics》1972,24(2):356-367
Values of the level intervals in the ground configurations 2s
2 2p
2, 2s
2 2p
3 and 2s
2 2p
4 have been critically compiled from laboratory observations and from observations of nebular and coronal forbidden transitions. The data are represented within experimental errors by means of semi-empirical extrapolation formulae which contain from 3 to 5 adjusted parameters. The results provide means for checking laboratory and astrophysical identifications and measurements. Tables of best level values are given for the configurations concerned. 相似文献
85.
Quaternary reactivation of Tertiary faults in the southeastern Korean Peninsula: Age constraint by optically stimulated luminescence dating 总被引:1,自引:0,他引:1
Jin-Han Ree Young-Joon Lee Ed J. Rhodes Youngdo Park Sung-Tack Kwon Ueechan Chwae Jeong-Soo Jeon Bongjoo Lee 《Island Arc》2003,12(1):1-12
Abstract Two groups of Quaternary faults occur in the southeastern Korean Peninsula. The first group is north-northeast-striking, high-angle dextral strike–slip faults. The second group is north-northeast-striking, low-angle reverse faults that represent the reactivation of the pre-existing normal faults. Optically stimulated luminescence dating of Quaternary sediments cut by one of the reverse faults constrains the faulting age to post-32 Ka. These faults seem to be capable of further slip under the current tectonic stress regime, as determined by recent earthquake events in northeast Asia. Therefore, the traditional concept that the southeastern Korean Peninsula is seismically stable should be reappraised. 相似文献
86.
87.
Carlos Sancho Jos Luis Pea Felipe Rivelli Ed Rhodes Arsenio Muoz 《Journal of South American Earth Sciences》2008,26(1):68-77
The development and evolution of the Tilcara alluvial fan, in the Quebrada de Humahuaca (Andean Eastern Cordillera, NW Argentina), has been analysed by using geomorphological mapping techniques, sedimentological characterisation of the deposits and OSL chronological methods. It is a complex segmented alluvial fan made up of five evolutionary stages (units Qf1, Qf2, Qf3, Qf4 and Qf5) developed under arid climatic environments as well as compressive tectonic conditions. Segmentation processes, including aggradation/entrenchment cycles and changes in the location of the depositional lobe, are mainly controlled by climatic and/or tectonic changes as well as channel piracy processes in the drainage system. Alluvial fan deposits include debris flows, sheet flows and braided channel facies associated with high water discharge events in an arid environment. The best mean OSL age estimated for stage Qf2 is 84.5 ± 7 ka BP. In addition, a thrust fault affecting these deposits has been recognized and, as a consequence, the compressive tectonics must date from the Upper Pleistocene in this area of the Andean Eastern Cordillera. 相似文献
88.
Mathematical Geosciences - 相似文献
89.
Ed Sobey 《Journal of Oceanography》1975,31(6):235-242
Composite pictures of the areal extent of Antarctic sea ice derived from satellite photographs, show that the growth and the rate of growth of the pack ice compare favorably to the values previously estimated on other bases. Anomalous growth patterns are found in the Weddell Sea. Possible causes of this anomaly include surface and subsurface advection of ice crystals. The rate of retrogradation of the pack ice is found to exceed the rate of progradation. 相似文献
90.