全文获取类型
收费全文 | 369篇 |
免费 | 63篇 |
国内免费 | 58篇 |
专业分类
测绘学 | 20篇 |
大气科学 | 1篇 |
地球物理 | 59篇 |
地质学 | 374篇 |
天文学 | 1篇 |
综合类 | 25篇 |
自然地理 | 10篇 |
出版年
2023年 | 1篇 |
2022年 | 9篇 |
2021年 | 6篇 |
2020年 | 13篇 |
2019年 | 13篇 |
2018年 | 6篇 |
2017年 | 10篇 |
2016年 | 19篇 |
2015年 | 9篇 |
2014年 | 24篇 |
2013年 | 10篇 |
2012年 | 21篇 |
2011年 | 22篇 |
2010年 | 26篇 |
2009年 | 30篇 |
2008年 | 22篇 |
2007年 | 25篇 |
2006年 | 28篇 |
2005年 | 25篇 |
2004年 | 29篇 |
2003年 | 19篇 |
2002年 | 13篇 |
2001年 | 14篇 |
2000年 | 13篇 |
1999年 | 12篇 |
1998年 | 9篇 |
1997年 | 14篇 |
1996年 | 11篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1979年 | 1篇 |
排序方式: 共有490条查询结果,搜索用时 309 毫秒
61.
This study develops a three-dimensional heterogeneous numerical model to simulate the water inrush process and predict the water yield for mineral exploration in Yangzhuang Iron Mine in Anhui Province. To identify the hydrogeological parameters of the aquifer in the study area, the model was calibrated and validated using the observed heads through the integrated trial-and-error and automated techniques. Also, the sensitivity analysis of the model was performed to evaluate the uncertainty associated with the calibrated model. According to the mine construction plan at different mining levels of -500 m, -600 m, and -700 m, the calibrated model was then applied to predict the water yields dependent on the different mining levels. As indicated by the prediction results, the numerical simulation model can systematically describe the groundwater system in the mining area and determine the source of water inrush in this iron mine. In conclusion, numerical analyses carried out in this study can provide guidance to decision-makers in balancing the iron ore mining and mine dewatering in the future. 相似文献
62.
准确预测煤岩破裂震源方位,确定采掘工作面重点灾害区域,可以使煤岩动力灾害防治措施更为有效.根据煤岩变形破裂电磁效应规律和电磁波基础理论,提出了一种利用电磁信号能量来确定局部震源方位的方法,并通过实验室定向接收实验和平煤十矿现场测试验证该方法的有效性.结果表明,电磁信号强度随着煤岩体应力状态变化而变化;两个正交天线接收的电磁信号能量分别与各自接收夹角余弦值的平方成正比,利用此比例关系可以确定震源的方位;电磁信号定位方法与静态指标法预测局部区域危险性具有较好的检验一致性.研究成果为煤岩动力灾害重点灾害区域的判定提供依据. 相似文献
63.
64.
广西南丹大厂矿区地震活动特征分析 总被引:1,自引:0,他引:1
本文收集了2009年12月至2010年4月广西南丹大厂矿区地震监测台网记录到的421次ML≥0.5可定位地震事件(含爆破)时空分布情况, 从实际调查和波形特征分析排除爆破记录后, 研究震级较大的几次矿震震源机制解, 按小时段统计爆破频次与能量释放关系。 结果表明, 矿震断裂走向与区域构造较为一致。 矿山地下开采量增加以及之前出现的近半年历史上罕见的干旱气象因素, 在震级较大的人工爆破触发下, 影响了局部构造应力场的稳定性, 由此引发了一系列矿震。 相似文献
65.
《Chemie der Erde / Geochemistry》2017,77(4):614-624
Water samples (springs, creeks, mine adits) from different former mining districts of the Harz Mountains and the nearby Kupferschiefer (copper shale) basin of Sangerhausen were analysed for major ions and trace metals. Due to more intensive water rock interactions including the ore minerals, the mine water concentrations of main components and trace metals are generally higher compared to non mining affected surface waters of the mountain range. Furthermore, the content of major ions in mine water is enriched by mixing processes with saline waters from Permian layers in the Kupferschiefer district and at the deeper levels of the mines in the Upper Harz Mountains. The waters of the different mining districts can be distinguished by trace metal occurrences and concentrations derived from the different ore bodies. Water from the Kupferschiefer mines shows the highest Na, Cl, Cu, Mo and U concentrations, whereas a combination of elevated As and Se concentrations is typical for most of the samples from the mines around St. Andreasberg. However, there are exceptions, and some water samples of all the investigated mining districts do not follow these general trends. Despite the influence of mining activities and ore mineralisation, hydrochemical effects due to rain water dilution can be seen in most of the waters. According to the elevation of the mountain range, higher precipitation rates decrease the ion concentrations in the waters of springs, creeks and mine adits. 相似文献
66.
67.
To study the geochemical anomaly structure of multi-element associations in the South Mining District of the Fenghuangshan Copper Mine,samples were collected and analyzed for their trace element contents.Multi-element anomaly associations were divided according to the correlations between Cu and each of the other elements,and the distribution characteristics of multi-element anomaly associations were also described.Among them,the anomaly distribution of metallogenic element Cu indicates the environment of mineralization.This study provided the basis for research on the metallogenic prediction and geochemistry of the Fenghuangshan Copper Mine. 相似文献
68.
69.
Michael F. Gazley Julie K. Vry Ettienne du Plessis Monica R. Handler 《Journal of Geochemical Exploration》2011
Stratigraphy, structure and host-rock chemistry are dominant controls on the location of Au in Archaean greenstone-hosted Au deposits, but the stratigraphy in such deposits is seldom obvious due to the monotonous nature of the host rocks or pervasive alteration associated with Au mineralisation. Portable, hand-held, X-ray fluorescence (pXRF) spectrometry provides a method to rapidly collect large amounts of whole-rock geochemical data that can yield new insights into both stratigraphy and Au localisation. Here we present results of pXRF analyses of samples from a representative section through Au-mineralised amphibolite-facies metabasaltic rocks at Plutonic Gold Mine, Western Australia. These data illustrate a geochemical stratigraphy in which individual lava flows can be identified on the basis of element concentrations. The most evolved basalts are at the structural base of the succession, and the least evolved at the top of the sequence, confirming previous geochemical interpretations and textural evidence that the sequence is overturned, and demonstrating for the first time that the presented section does not involve significant structural repetition. In conjunction with Au assay data, the pXRF data reveal that Au commonly occurs along basalt flow boundaries. The elemental concentration data clearly demonstrates for the first time the stratigraphic control on Au mineralisation that is not readily apparent at the macroscopic level. The methods described in this paper are readily applied, and have the potential to enhance the understanding of otherwise unclear stratigraphy and its control on mineralisation in many different types of deposits worldwide. 相似文献
70.
为实现矿山地质环境评价的科学、快捷和实用,编制了“矿山地质环境评价系统”软件.该文介绍其理论基础、开发思路及主要功能,并通过实例介绍其应用效果. 相似文献