全文获取类型
收费全文 | 305篇 |
免费 | 64篇 |
国内免费 | 83篇 |
专业分类
测绘学 | 9篇 |
地球物理 | 11篇 |
地质学 | 397篇 |
综合类 | 29篇 |
自然地理 | 6篇 |
出版年
2024年 | 2篇 |
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 9篇 |
2020年 | 8篇 |
2019年 | 13篇 |
2018年 | 5篇 |
2017年 | 8篇 |
2016年 | 6篇 |
2015年 | 9篇 |
2014年 | 36篇 |
2013年 | 26篇 |
2012年 | 23篇 |
2011年 | 40篇 |
2010年 | 22篇 |
2009年 | 41篇 |
2008年 | 30篇 |
2007年 | 26篇 |
2006年 | 21篇 |
2005年 | 17篇 |
2004年 | 12篇 |
2003年 | 10篇 |
2002年 | 7篇 |
2001年 | 7篇 |
2000年 | 8篇 |
1999年 | 11篇 |
1998年 | 10篇 |
1997年 | 9篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 8篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 1篇 |
排序方式: 共有452条查询结果,搜索用时 562 毫秒
31.
铁法煤田煤储层渗透性预测 总被引:6,自引:3,他引:3
煤储层的渗透性预测是煤层气开发前必须的储层评价工作。评价方法是依据围岩节理及煤层裂隙的宏观、微观统计分析,寻找区内裂隙发育带及其走向,预测高渗透区的分布。 相似文献
32.
青海东北部木里煤田控煤构造样式与找煤预测 总被引:4,自引:0,他引:4
在系统分析木里煤田构造格局和构造控煤特征的基础上,将本区控煤构造样式划分为压缩、剪切、滑动3大类和8种类型。揭示了控煤构造样式与煤系赋存之间的关系,木里煤田控煤构造样式以压缩为主,分布广泛,部分矿区构造样式表现为剪切和层滑,各矿区煤系赋存状态受煤田构造格局的控制,具有南北分带、东西分段的特征。煤田边缘构造复杂,控煤构造样式以逆冲前锋型、逆冲断夹块型、逆冲-褶皱型和对冲型为主,含煤向斜形态多不完整;煤田中部地质构造相对简单,控煤构造样式以褶皱-断裂型为特征,含煤岩系赋存稳定,是有利的勘查开发区段。 相似文献
33.
34.
35.
美国中部伊利诺伊煤田(跨伊利诺伊、印第安纳、肯塔基等三个州)的含煤地层为上石炭统宾夕法尼亚系。美国印第安纳地质研究所2006年编制的印第安纳州基岩综合地层柱状图建立了宾夕法尼亚系含煤地层的岩相层序,现将此岩相层序介绍到国内,对我们了解美国晚古生代煤田地质及阅读国外文献资料颇有帮助。 相似文献
36.
37.
我国许多煤矿区,由于地下水频繁突入,造成淹井或因突水威胁使大量煤炭资源难以开发。因此,准确预测矿井涌水量,为矿井防治水提供依据,对煤矿床安全开采和长远发展至关重要。以宁东煤炭基地麦垛山煤矿为例,采用解析法、水文地质比拟法和三维渗流数值法等六种预测方法,对该煤矿11采区110203、110208工作面2#煤顶板直罗组底部砂岩含水层进行了涌水量预测。通过各种方法的分析比较,最后推荐采用最小二乘比拟法预算结果做最终矿井涌水量。 相似文献
38.
福建煤田地质构造复杂,断层发育,岩层极其破碎且较松软,泥岩受挤压破碎为薄片状或烂泥状,给钻探施工造成许多困难,比如泥页岩水化膨胀,孔壁失稳导致孔内坍塌严重等。采用绳索取心技术,优选金刚石钻头,科学确定泥浆配比和钻进参数,成功解决了这些孔内技术难题,提高了钻探效率,降低了生产成本,取得的施工经验可供该矿区或该类地层的钻探施工借鉴。 相似文献
39.
Mine-drainage water from coal mines of Kerman region,Iran 总被引:1,自引:0,他引:1
Two types of mine-drainage water were recognized in Kerman coalfield, namely neutral to alkaline and acid (AMD). Both types contain a high level of trace-metal concentrations with a higher level in AMD. Trace metals from the coal-mine waters of Kerman coalfield are mainly present as adsorption on Fe and Mn oxide and hydroxide particles, and to a lesser extent as sulfate, simple metal ions and as metal sorption on clay particles and hydrous aluminum oxides. 相似文献
40.
N. S. Krishnamurthy V. Ananda Rao Dewashish Kumar K. K. K. Singh Shakeel Ahmed 《Journal of the Geological Society of India》2009,73(5):639-650
Exploration and exploitation of coal seams is one of the major resources for the energy sector in any country but at the same
time water filled voids/water logged areas in the old workings of these seams are very critical problems for the coal mining
industry. In such situations, disasters like inundation, landslides, collapsing of the old seams may occur. In this regard,
it is necessary to find out the water saturated/water filled voids and zones in the mining areas. Since no established technique
is available to find such zones, an experimental study using Electrical Resistivity Imaging (ERI) has been carried out in
one of the coal mining areas near Dhanbad, to find out the feasibility of finding the barrier thickness and the water logged
area in underground coal mines. The area under study forms part of Jharia coalfield in Dhanbad district, Jharkhand state.
The coal bearing rocks of Barakar Formation of Lower Permian age (Gondwana period) occur in the area under a thin cover (10
m to15 m) of soil and or alluvium. Coal bearing Barakar Formations consist mainly of sandstone of varying grain size, intercalation
of shale and sandstone, grey and carbonaceous-shale and coal seams.
Since the water saturation reduces the resistivity of a formation to a large extent, water filled voids and old coal workings
are expected to have significant resistivity contrast with the surrounding host rock. Hence, ERI technique was applied in
such an environment as this technique uses high-density data acquisition both laterally and vertically by using multiple number
of electrodes. Along with ERI, mise-à-la-masse (also called charged body) technique was also employed at one of the promising
sites to find out the connectivity of water logged areas and also detection of these old workings from the surface measurements
was analyzed. The interpreted 2D resistivity sections have clearly indicated the water bearing zone(s) along the profile which
was well confirmed with the existing water level in the nearby borewells. On the other hand, this technique did not identify
the size of the coal pillar and gallery (air filled voids), which might be due to the small size of the voids (i.e. about
2 m × 2 m) below a depth of 15m and more but have indicated altogether as a high resistive zone ranging from 600–1000 Ohm-m. 相似文献