全文获取类型
收费全文 | 97385篇 |
免费 | 15458篇 |
国内免费 | 20053篇 |
专业分类
测绘学 | 12171篇 |
大气科学 | 12442篇 |
地球物理 | 18668篇 |
地质学 | 48648篇 |
海洋学 | 11407篇 |
天文学 | 6889篇 |
综合类 | 7215篇 |
自然地理 | 15456篇 |
出版年
2024年 | 385篇 |
2023年 | 1007篇 |
2022年 | 2799篇 |
2021年 | 3370篇 |
2020年 | 3390篇 |
2019年 | 4132篇 |
2018年 | 3127篇 |
2017年 | 3786篇 |
2016年 | 3889篇 |
2015年 | 4276篇 |
2014年 | 5300篇 |
2013年 | 5516篇 |
2012年 | 5816篇 |
2011年 | 6159篇 |
2010年 | 5104篇 |
2009年 | 6376篇 |
2008年 | 6200篇 |
2007年 | 6865篇 |
2006年 | 6692篇 |
2005年 | 5962篇 |
2004年 | 5563篇 |
2003年 | 5085篇 |
2002年 | 4372篇 |
2001年 | 3865篇 |
2000年 | 3596篇 |
1999年 | 3290篇 |
1998年 | 2839篇 |
1997年 | 2344篇 |
1996年 | 2086篇 |
1995年 | 1770篇 |
1994年 | 1742篇 |
1993年 | 1475篇 |
1992年 | 1133篇 |
1991年 | 844篇 |
1990年 | 660篇 |
1989年 | 583篇 |
1988年 | 418篇 |
1987年 | 269篇 |
1986年 | 190篇 |
1985年 | 133篇 |
1984年 | 63篇 |
1983年 | 48篇 |
1982年 | 49篇 |
1981年 | 38篇 |
1980年 | 47篇 |
1979年 | 47篇 |
1978年 | 59篇 |
1977年 | 42篇 |
1976年 | 9篇 |
1954年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
191.
断层相关褶皱理论在准噶尔盆地南缘山前带构造研究的应用 总被引:8,自引:4,他引:4
利用断层相关褶皱的构造几何分析方法,对准噶尔盆地南缘山前复杂构造带内基于地震剖面进行了构造解析,搭建了中、东段的构造轮廓和构造组合样式,认为东段阜康断裂带主要表现为至地表的推覆逆掩。由于位移量大部分转移至地表,阜康断裂带的前陆部分无喜山期构造带;西段造山带内的挤压往前陆方向传递过程中以前列式不断释放其位移量,造成在纵向上呈现三排主要的断层相关褶皱带。根据正演平衡地质剖面制作技术对山前复杂构造区地震剖面反射波的构造识别进行了模拟与探讨。 相似文献
192.
193.
194.
195.
Chen Zhangli 《中国地震研究》2001,15(4):329-345
In the article the author looks back the hard development course and great progress in earth quake science and technology in China during the last near a half of century and expounds the following 3 aspects: (1) The strong desire of the whole society to mitigate seismic disasters and reduce the effect of earthquakes on social-economic live is a great driving force to push forward the development of earthquake science and technology in China; (2) To better ensure people‘ s life and property, sustainable economic development, and social stability is an essential purpose to drive the development of earthquake science and technology in China; and (3) To insist on the dialectical connection of setup of technical system for seismic monitoring with the scientific research of earthquakes and to better handle the relation between crucial task, current scientif ic level, and the feasibility are the important principles to advance the earthquake science and technology in China. Some success and many setbacks in earthquake disaster mitigation consistently enrich our knowledge regarding the complexity of the conditions for earthquake occurrence and the process of earthquake preparation, promote the reconstruction and modernization of technical system for earthquake monitoring, and deepen the scientific research of earthquakes. During the last 5 years, the improvement and modernization of technical system for earthquake monitoring have clearly provided the technical support to study and practice of earthquake prediction and pre caution, give prominence to key problems and broaden the field of scientific research of earth quakes. These have enabled us to get some new recognition of the conditions for earthquake oc currence and process of earthquake preparation, characteristics of seismic disaster, and mecha nism for earthquake generation in China‘s continent. The progress we have made not only en courages us to enhance the effectiveness of earthquake disaster mitigation, but also provides a basis for accelerating further development of earthquake science and technology in China in the new century, especially in the 10th five-year plan. Based on the history reviewed, the author sets forth a general requirement for develop ment of earthquake science and technology in China and brings out 10 aspects to be stressed and strengthened at present and in the future. These are: upgrade and setup of the network of digitized seismic observation; upgrade and setup of the network for observation of seismic pre cursors; setup of the network for observation of strong motion; setup of the laboratories for ex periment on seismic regime; establishment of technical system for seismic information, emer gency command and urgent rescue; research on short-term and imminent earthquake predic tion; research on intermediate- and long-term earthquake prediction; research on attenuation of seismic ground motion, mechanism for seismic disaster, and control on seismic disaster; ba sic research fields related to seismology and geoscience. We expect that these efforts will signifi cantly elevate the level of earthquake science and technology in China to the advanced interna tional level, improve theories, techniques, and methods for earthquake precaution and predic tion, and enhance the effectiveness of earthquake disaster mitigation. 相似文献
196.
197.
P. A. Patsis 《Monthly notices of the Royal Astronomical Society》2005,358(2):305-315
We investigate the morphological relation between the orbits of the central family of periodic orbits ( x 1 family) and the bar itself using models of test particles moving in a barred potential. We show that different bar morphologies may have as a backbone the same set of x 1 periodic orbits. We point out that by populating initially axisymmetric stellar discs exponentially with test particles in circular, or almost circular motion, we may end up with a response bar which reveals a shape different in crucial details from that of the individual stable x 1 orbits. For example, a bar model in which the x 1 orbits are pure ellipses may have a much more complicated response morphology. This depends on the particular invariant curves around x 1 , which are populated in each model. 相似文献
198.
199.
青藏块体东北缘地壳水平运动状态 总被引:10,自引:6,他引:4
应用青藏块体东北缘1999~2003年多期GPS观测资料,计算了不同时段GPS点水平运动速率。通过分析发现:甘青块体可分为东部块体和西部块体,东、西部块体的运动状态存在明显的差异;受2001年11月14日昆仑Ms8.1地震的影响,震后地壳运动状态发生了明显的改变。 相似文献
200.
本文讨论了利用LAMOST作银河系研究的科学意义及可能性;并提出具体实施LAMOST/GAIAXY计划的初步方案。 相似文献