全文获取类型
收费全文 | 50篇 |
免费 | 9篇 |
国内免费 | 15篇 |
专业分类
测绘学 | 5篇 |
大气科学 | 6篇 |
地球物理 | 25篇 |
地质学 | 19篇 |
海洋学 | 10篇 |
综合类 | 8篇 |
自然地理 | 1篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 5篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 6篇 |
2012年 | 1篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2007年 | 4篇 |
2006年 | 1篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有74条查询结果,搜索用时 218 毫秒
31.
阿尔金活动断裂带的运动学和动力学特征 总被引:6,自引:0,他引:6
位于喜马拉雅碰撞带后陆的阿尔金活动断裂带,是自西向东逐步形成的左旋走滑断裂。早期以逆冲活动为主,晚期以走滑活动为主。距今0.35Ma(中更新世)以来,平均左旋走滑速率为4.9±0.4mm/a,平均水平错动量是垂直错动量的12.3倍。晚更新世晚期至全新世时期发生过5次古地震,平均复现期为800年左右。 相似文献
32.
通过对地震断层陡坎演为过程的分析,应用均匀物质扩散理论建立地震断层陡坎的形态方程,推断古地震断层陡坎的年龄,从而确定古地震事件的期次及年代。用该方法对二台活断层古地震断层陡坎进行计算,所得结果与用其它方法确定的古地震事件的期次及年代对应较好。 相似文献
33.
Kadir Gürgey Bernd R.T. Simoneit Zühtü Batı İsmail H. Karamanderesi Baki Varol 《Applied Geochemistry》2007
The KB-5 well is located at the intersection of the geothermally active Menderes and Gediz graben systems in western Turkey. Significant volumes of “petroleum-like material” (PLM) with its associated thermal water (120 °C) erupted onto the surface during drilling from a depth of 120–132 m (i.e., from the claystone and marl-rich Early to Middle Pliocene Kolonkoya formation). The purpose of this paper is: (1) to characterize this PLM, (2) to assess the source characteristics from which the PLM was likely generated, and (3) to recognize the generation mechanism considering the geothermal-gradual versus the hydrothermal-rapid processes. Analytical organic geochemistry using thin layer chromatographic separation followed by gas chromatography–mass spectrometry (GC–MS) was carried out. 相似文献
34.
35.
Depositional ages and characteristics of Middle–Upper Jurassic and Lower Cretaceous lacustrine deposits in southeastern Mongolia
下载免费PDF全文
![点击此处可从《Island Arc》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Hitoshi Hasegawa Hisao Ando Noriko Hasebe Niiden Ichinnorov Tohru Ohta Takashi Hasegawa Masanobu Yamamoto Gang Li Bat‐Orshikh Erdenetsogt Ulrich Heimhofer Takayuki Murata Hironori Shinya G. Enerel G. Oyunjargal O. Munkhtsetseg Noriyuki Suzuki Tomohisa Irino Koshi Yamamoto 《Island Arc》2018,27(3)
Lower Cretaceous lacustrine oil shales are widely distributed in southeastern Mongolia. Due to the high organic carbon content of oil shale, many geochemical studies and petroleum exploration have been conducted. Although most of the oil shales are considered to be Early Cretaceous in age, a recent study reveals that some were deposited in the Middle Jurassic. The present study aims at establishing depositional ages and characteristics of the Jurassic and Cretaceous lacustrine deposits in Mongolia. The Lower Cretaceous Shinekhudag Formation is about 250 m thick and composed of alternating beds of shale and dolomite. The Middle Jurassic Eedemt Formation is about 150 m thick and composed of alternating beds of shale, dolomitic marl, and siltstone. The alternations of shale and dolomite in both formations were formed by lake level changes, reflecting precipitation changes. Shales were deposited in the center of a deep lake during highstand, while dolomites were formed by primary precipitation during lowstand. Based on the radiometric age dating, the Shinekhudag Formation was deposited between 123.8 ±2.0 Ma and 118.5 ±0.9 Ma of the early Aptian. The Eedemt Formation was deposited at around 165–158 Ma of Callovian–Oxfordian. The calculated sedimentation rate of the Shinekhudag Formation is between 4.7 ±2.6 cm/ky and 10.0 ±7.6 cm/ky. Shales in the Shinekhudag Formation show micrometer‐scale lamination, consisting of algal organic matter and detrital clay mineral couplets. Given the average thickness of micro‐laminae and calculated sedimentation rate, the micro‐lamination is most likely of varve origin. Both Middle–Upper Jurassic and Lower Cretaceous lacustrine oil shales were deposited in intracontinental basins in the paleo‐Asian continent. Tectonic processes and basin evolution basically controlled the deposition of these oil shales. In addition, enhanced precipitation under humid climate during the early Aptian and the Callovian–Oxfordian was another key factor inducing the widespread oil shale deposition in Mongolia. 相似文献
36.
Ocean Dynamics - The Arctic Ocean is undergoing significant changes, with rapid sea ice decline, unprecedented freshwater accumulation, and pronounced regional sea level rise. In this paper, we... 相似文献
37.
Nitrate subsurface transport and losses in response to its initial distributions in sloped soils: An experimental and modelling study 总被引:1,自引:0,他引:1
Meixiang Xie Jirka imnek Zhanyu Zhang Pingcang Zhang Jinxin Xu Qingming Lin 《水文研究》2019,33(26):3282-3296
Transport and losses of nitrate from sloped soils are closely linked to nitrogen fertilizer management. Previous studies have always focused on different types of fertilizer applications and rarely analysed various initial nitrate distributions as a result of nitrogen fertilizer applications. Under certain conditions, both subsurface lateral saturated flow and vertical leaching dominate nitrate losses. Soil tank experiments and HYDRUS‐2D modelling were used to better understand the subsurface nitrate transport and losses through lateral saturated flow and vertical leaching under various initial nitrate distributions. Low (L: 180 mg L?1), normal (N: 350 mg L?1), and high (H: 500 mg L?1) nitrate concentrations were used in five different distributions (NNNN, NLLN, LHHL, LNLN, and HNHN) along the slope of the tank. The first two treatments (NNNN and NLLN) were analysed both experimentally and numerically. Experiments were conducted under 12 rainfall events at intervals of 3 days. The HYDRUS‐2D model was calibrated and validated against the experimental data and demonstrated good model performance. The other three treatments (LHHL, LNLN, and HNHN) were investigated using the calibrated model. Nitrate concentrations in purple sloped soils declined exponentially with time under intermittent rainfalls, predominantly in the upper soil layers. Non‐uniform initial nitrate distributions contributed to larger differences between four locations along the slope in deeper soil layers. The non‐uniform nitrate distribution either enhanced or reduced decreases in nitrate concentrations in areas with higher or lower initial nitrate concentrations, respectively. Higher nitrate concentrations at the slope foot and along the slope were reduced mainly by lateral flow and vertical leaching, respectively. Increasing nitrogen application rates increased subsurface nitrate losses. Mean subsurface lateral nitrate fluxes were twice as large as mean vertical leaching nitrate fluxes. However, due to longer leaching durations, total nitrate losses due to vertical leaching were comparable with those due to lateral flow, which indicated comparable environmental risks to surface waters and groundwater. 相似文献
38.
39.
40.
利用河源地区5个气象站1960—2016年的逐月平均气温、NOAA逐月海温等资料,采用线性倾向、Mann-Kendall检验等统计方法,分析了河源地区气温变化特征及其对ENSO事件的响应。结果表明:河源地区年平均气温及季平均气温均呈递增趋势,且夏、秋、冬季和年平均气温气温上升趋势显著;河源地区气温在20世纪80年代中后期—90年代末发生1次较为明显的由冷到暖的突变;年平均气温存在5~6、14~15及24 a的周期变化规律;在El Ni1o事件中,河源地区年平均气温有偏高趋势,La Ni1o事件,则反之;ENSO事件对气温的影响存在滞后性,对河源地区的气温影响最明显表现在次年。 相似文献