全文获取类型
收费全文 | 7017篇 |
免费 | 1877篇 |
国内免费 | 2072篇 |
专业分类
测绘学 | 88篇 |
大气科学 | 1741篇 |
地球物理 | 3397篇 |
地质学 | 1873篇 |
海洋学 | 3009篇 |
天文学 | 76篇 |
综合类 | 333篇 |
自然地理 | 449篇 |
出版年
2024年 | 54篇 |
2023年 | 155篇 |
2022年 | 216篇 |
2021年 | 284篇 |
2020年 | 313篇 |
2019年 | 425篇 |
2018年 | 319篇 |
2017年 | 302篇 |
2016年 | 307篇 |
2015年 | 379篇 |
2014年 | 407篇 |
2013年 | 416篇 |
2012年 | 451篇 |
2011年 | 455篇 |
2010年 | 361篇 |
2009年 | 449篇 |
2008年 | 432篇 |
2007年 | 592篇 |
2006年 | 484篇 |
2005年 | 430篇 |
2004年 | 433篇 |
2003年 | 379篇 |
2002年 | 344篇 |
2001年 | 293篇 |
2000年 | 292篇 |
1999年 | 272篇 |
1998年 | 268篇 |
1997年 | 220篇 |
1996年 | 222篇 |
1995年 | 217篇 |
1994年 | 188篇 |
1993年 | 151篇 |
1992年 | 117篇 |
1991年 | 107篇 |
1990年 | 57篇 |
1989年 | 48篇 |
1988年 | 46篇 |
1987年 | 28篇 |
1986年 | 11篇 |
1985年 | 9篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 1篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1954年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
301.
Traveltime biases in random media and the S-wave discrepancy 总被引:4,自引:0,他引:4
302.
303.
304.
Inversion for elastic parameters in weakly anisotropic media 总被引:1,自引:0,他引:1
Xuyao Zheng 《Geophysical Journal International》2004,159(3):1077-1089
305.
Seasonal Variation of the East Asian Subtropical Westerly Jet and Its Association with the Heating Field over East Asia 总被引:3,自引:0,他引:3
The structure and seasonal variation of the East Asian Subtropical Westerly Jet (EAWJ) and associations with heating fields over East Asia are examined by using NCEP/NCAR reanalysis data. Obvious differences exist in the westerly jet intensity and location in different regions and seasons due to the ocean-land distribution and seasonal thermal contrast, as well as the dynamic and thermodynamic impacts of the Tibetan Plateau. In winter, the EAWJ center is situated over the western Pacific Ocean and the intensity is reduced gradually from east to west over the East Asian region. In summer, the EAWJ center is located over the north of the Tibetan Plateau and the jet intensity is reduced evidently compared with that in winter. The EAWJ seasonal evolution is characterized by the obvious longitudinal inconsistency of the northward migration and in-phase southward retreat of the EAWJ axis. A good correspondence between the seasonal variations of EAWJ and the meridional differences of air temperature (MDT) in the mid-upper troposphere demonstrates that the MDT is the basic reason for the seasonal variation of EAWJ. Correlation analyses indicate that the Kuroshio Current region to the south of Japan and the Tibetan Plateau are the key areas for the variations of the EAWJ intensities in winter and in summer, respectively. The strong sensible and latent heating in the Kuroshio Current region is closely related to the intensification of EAWJ in winter. In summer, strong sensible heating in the Tibetan Plateau corresponds to the EAWJ strengthening and southward shift, while the weak sensible heating in the Tibetan Plateau is consistent with the EAWJ weakening and northward migration. 相似文献
306.
307.
308.
Rodrigo A. Miranda Erico L. Rempel Abraham C.-L. Chian Felix A. Borotto 《Journal of Atmospheric and Solar》2005,67(17-18):1852
There is increasing observational evidence of nonlinear wave–wave interactions in space and astrophysical plasmas. We first review a number of theoretical models of nonlinear wave–wave interactions which our group has developed in the past years. We next describe a nonlinear three-mode truncated model of Alfvén waves, involving resonant interactions of one linearly unstable mode and two linearly damped modes. We construct a bifurcation diagram for this three-wave model and investigate the phenomenon of intermittent chaos. The theoretical results presented in this paper can improve our understanding of intermittent time series frequently observed in space and astrophysical plasmas. 相似文献
309.
During the 20th century many floods of different intensity and extent have occurred on the Odra River and its tributaries. On the basis of long-term water level observations five major floods, that affected the entire upper and middle Odra River basin, were chosen for further analysis: June 1902, July 1903, August 1977, August 1985 and July 1997. However, hazardous floods were not only those that covered the whole upper and middle Odra River basin, so several local floods were also studied. Detailed historical analysis was made of meteorological conditions, with special emphasis on precipitation patterns and amounts. Then, on the basis of flood peak time occurrence, the stages of flood wave formation were formulated. The natural flood wave of the Odra River is often modified by hydro-technical infrastructure, the development and improvement of which is briefly described in this paper. In conclusion, a comparison of flood wave characteristics such as rising time, falling time, duration, peak flow and volume is presented. 相似文献
310.
我国地震海浪初步分析 总被引:1,自引:0,他引:1
总结了我国地震海浪的25次记录,在做初步分析后认为我国的地震海浪多由近海海洋地震引起,其多发地区为渤海沿岸与东南沿海一带.随着对沿海地区开发的深入,这类记载逐渐增多,受灾程度加大.另外分析了在社会历史变迁中,国家对海洋的开发政策、沿海开发下城市近海地理位置、沿海港口及海洋贸易的规模与地震海浪受灾程度之间的关系. 相似文献