全文获取类型
| 收费全文 | 1574篇 |
| 免费 | 436篇 |
| 国内免费 | 485篇 |
专业分类
| 测绘学 | 251篇 |
| 大气科学 | 171篇 |
| 地球物理 | 397篇 |
| 地质学 | 972篇 |
| 海洋学 | 282篇 |
| 天文学 | 31篇 |
| 综合类 | 136篇 |
| 自然地理 | 255篇 |
出版年
| 2024年 | 6篇 |
| 2023年 | 18篇 |
| 2022年 | 103篇 |
| 2021年 | 116篇 |
| 2020年 | 92篇 |
| 2019年 | 113篇 |
| 2018年 | 78篇 |
| 2017年 | 96篇 |
| 2016年 | 92篇 |
| 2015年 | 117篇 |
| 2014年 | 90篇 |
| 2013年 | 129篇 |
| 2012年 | 144篇 |
| 2011年 | 136篇 |
| 2010年 | 135篇 |
| 2009年 | 153篇 |
| 2008年 | 134篇 |
| 2007年 | 115篇 |
| 2006年 | 125篇 |
| 2005年 | 93篇 |
| 2004年 | 69篇 |
| 2003年 | 49篇 |
| 2002年 | 55篇 |
| 2001年 | 63篇 |
| 2000年 | 41篇 |
| 1999年 | 14篇 |
| 1998年 | 12篇 |
| 1997年 | 12篇 |
| 1996年 | 6篇 |
| 1991年 | 3篇 |
| 1990年 | 5篇 |
| 1975年 | 4篇 |
| 1974年 | 3篇 |
| 1973年 | 2篇 |
| 1966年 | 3篇 |
| 1965年 | 5篇 |
| 1964年 | 4篇 |
| 1963年 | 4篇 |
| 1962年 | 2篇 |
| 1957年 | 7篇 |
| 1954年 | 2篇 |
| 1950年 | 2篇 |
| 1944年 | 3篇 |
| 1943年 | 3篇 |
| 1942年 | 3篇 |
| 1941年 | 3篇 |
| 1933年 | 3篇 |
| 1926年 | 2篇 |
| 1923年 | 2篇 |
| 1922年 | 2篇 |
排序方式： 共有2495条查询结果，搜索用时 250 毫秒
81.
笔者从地下地质工程和上水库工程地质调查这两个特殊问题论述了工程物探应用的对策和实效,具有一定的实用性和理论依据,对今后在抽水蓄能电站工程地质勘察中应用工程物探有一定的参考意义。 相似文献
82.
Abstract: 3–D velocity images of the crust beneath the northern margin of the North China Plate have been constructed using P-wave travel time residuals of the latest earthquakes, with the data supplied by Chinese seismic networks.
The seismic image results indicate that there is a lateral heterogeneity in the crust beneath the northern part of the North China block. The velocity images of the upper crust show features closely related to the tectonic features on the surface. It can be seen from these velocity images of the vertical sections, and from the horizontal slice images at depths of 11 and 16 km that there exist East-West and North-East structures. The images indicate that the juncture zone of basin–and–range terrain is between the blue-colored high–velocity block corresponding to the Yanshan mountain range that developed during the Yanshan period in northwest Beijing and the green low-velocity area corresponding to the North China basin in southeast Beijing (Fig. 5). The juncture zone between high-velocity and low–velocity, and EW and NE fault zones have significant ore-control effects. From the chart of epicenters in the northern region of North China, we find that the epicenters of earthquakes are almost entirely distributed within the NE strip. Almost all major earthquakes took place in the transition strip between the high and low-velocity zones in the crust. The distribution of epicenters also reflects the strikes of known NE–faults. From the image sections along the latitude, we find that in the area between 114.0 E –118.0 E , there is a blue high-velocity block standing upright from the Moho to the upper crust (Fig. 6), from which can be deduced that some materials such as magma moved upward from the upper mantle during the history of its geological development. 相似文献
The seismic image results indicate that there is a lateral heterogeneity in the crust beneath the northern part of the North China block. The velocity images of the upper crust show features closely related to the tectonic features on the surface. It can be seen from these velocity images of the vertical sections, and from the horizontal slice images at depths of 11 and 16 km that there exist East-West and North-East structures. The images indicate that the juncture zone of basin–and–range terrain is between the blue-colored high–velocity block corresponding to the Yanshan mountain range that developed during the Yanshan period in northwest Beijing and the green low-velocity area corresponding to the North China basin in southeast Beijing (Fig. 5). The juncture zone between high-velocity and low–velocity, and EW and NE fault zones have significant ore-control effects. From the chart of epicenters in the northern region of North China, we find that the epicenters of earthquakes are almost entirely distributed within the NE strip. Almost all major earthquakes took place in the transition strip between the high and low-velocity zones in the crust. The distribution of epicenters also reflects the strikes of known NE–faults. From the image sections along the latitude, we find that in the area between 114.0 E –118.0 E , there is a blue high-velocity block standing upright from the Moho to the upper crust (Fig. 6), from which can be deduced that some materials such as magma moved upward from the upper mantle during the history of its geological development. 相似文献
83.
84.
ＳｔｕｄｙｏｆＣｕｒｉｅｉｓｏｔｈｅｒｍａｌｓｕｒｆａｃｅｉｎＳｉｃｈｕａｎＢａｓｉｎａｎｄｔｈｅｓｅｉｓｍｉｃａｒｅａｏｎｉｔｓｗｅｓｔｅｒｎｍａｒ┐ｇｉｎＸＩＡＮＺＨＡＮＧ（张先），ＸＩ－ＦＥＮＧＨＵ（虎喜凤），ＪＩＮＧ－ＸＩＵＳＨＥＮ（沈京秀... 相似文献
85.
ＴｈｅＭＴｉｎｖｅｒｓｉｏｎｆｏｒｃｏｎｄｕｃｔｉｖｉｔｙａｎｉｓｏｔｒｏｐｙａｎｄＥＤＡｐｒｅｃｕｒｓｏｒ，ｓｔｒｅｓｆｉｅｌｄａｎｄｄｅｆｏｒ┐ｍａｔｉｏｎｂａｎｄｉｎｔｈｅＥａｒｔｈｓｄｅｅｐｃｒｕｓｔＣＨＡＮＧ－ＹＯＵＬＩＮ（林长佑），Ｃ... 相似文献
86.
高围压下冻土强度弱化的机理分析 总被引：7，自引：5，他引：2
围压作用下,影响冻结砂土强度弱化的主要原因是孔隙冰的压融,矿物颗粒细化的微裂隙的发育。影响冻结粉质粘土强度弱化的主要原因是孔隙冰的压融和微裂隙的发育,这些过程是不独立存在的,而是共同影响,共同作用,从而导致了冻土强度的弱化。 相似文献
87.
88.
89.
在GIS技术支持下建立的雨洪监控系统,为及时、合理地利用雨洪,节约开支提供了很好的保障,本文介绍了雨洪监控系统的应用和工程实践中的问题。 相似文献
90.