全文获取类型
收费全文 | 1161篇 |
免费 | 196篇 |
国内免费 | 160篇 |
专业分类
测绘学 | 108篇 |
大气科学 | 150篇 |
地球物理 | 479篇 |
地质学 | 163篇 |
海洋学 | 169篇 |
天文学 | 181篇 |
综合类 | 28篇 |
自然地理 | 239篇 |
出版年
2024年 | 8篇 |
2023年 | 13篇 |
2022年 | 20篇 |
2021年 | 26篇 |
2020年 | 39篇 |
2019年 | 43篇 |
2018年 | 25篇 |
2017年 | 36篇 |
2016年 | 38篇 |
2015年 | 38篇 |
2014年 | 37篇 |
2013年 | 57篇 |
2012年 | 34篇 |
2011年 | 44篇 |
2010年 | 60篇 |
2009年 | 62篇 |
2008年 | 70篇 |
2007年 | 71篇 |
2006年 | 107篇 |
2005年 | 71篇 |
2004年 | 67篇 |
2003年 | 53篇 |
2002年 | 51篇 |
2001年 | 51篇 |
2000年 | 42篇 |
1999年 | 38篇 |
1998年 | 35篇 |
1997年 | 20篇 |
1996年 | 45篇 |
1995年 | 24篇 |
1994年 | 26篇 |
1993年 | 31篇 |
1992年 | 21篇 |
1991年 | 16篇 |
1990年 | 21篇 |
1989年 | 19篇 |
1988年 | 20篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1954年 | 4篇 |
排序方式: 共有1517条查询结果,搜索用时 0 毫秒
1.
2.
3.
A comparison of two three-dimensional numerical modeling systems for tidal elevations and velocities in the coastal waters is presented. The two modeling systems are: (1) the Princeton Ocean Model (POM) and (2) the MIKE 3 flow model. The model performance results for Singapore's coastal waters show that the predicted tidal elevations from the two hydrodynamic modeling systems are almost identical and are in very good agreement with field measurement data. The simulated tidal current velocities match well with field measurement data at the selected stations, but it seems that the POM provides the slightly better simulation, compared to the MIKE 3 flow model. The depth profiles of the velocities obtained from the two modeling systems may be greatly different at some time, due to the vertical diffusion coefficient calculated from different turbulent sub-models in the two modeling systems. The POM generally predicts larger peak tidal velocities. The maximum speed differences for the model results from the two modeling systems occur in the top and differ from time to time and from location to location, reaching up to 20%. 相似文献
4.
5.
The S-velocity structure of the East Asian mantle from inversion of shear and surface waveforms 总被引:15,自引:0,他引:15
Wolfgang Friederich 《Geophysical Journal International》2003,153(1):88-102
6.
7.
Field vibration mitigation by honeycomb WIB for pile foundations of a high-speed train viaduct 总被引:5,自引:0,他引:5
Environmental vibrations from recent high-speed trains are becoming a special concern in the civil and environmental engineering field since they can give detrimental effects to residents, sensitive equipments and high-tech production facilities in the vicinity of train tacks. Herein, aiming at the vibration mitigation for a specific high-tech industrial area, the low-frequency vibrations from a train viaduct are targeted over an anticipated range. A theoretically designed innovative countermeasure, called honeycomb wave impeding barrier (WIB) for a wave impeding barrier, is introduced and its effects are investigated by computer simulation. The present WIB is based on the wave dispersion phenomenon that can modulate the incoming wavelengths into the shorter wavelengths, creating an apparent wave cut-off characteristic in the wave field across WIB installation area. The shorter wavelengths are further impeded due to the impedance ratio of the WIB walls and in-fill materials and absorbed by the in-fills more. The three-dimensional FEM simulation demonstrates a dramatic reduction effect that is difficult to achieve by conventional measures. 相似文献
8.
9.
Green''''s functions for uniformly distributed loads acting on an inclined line in a poroelastic layered site 总被引:4,自引:0,他引:4
Based on one type of practical Biot's equation and the dynamic-stiffness matrices of a poroelastic soil layer and half-space, Green's functions were derived for uniformly distributed loads acting on an inclined line in a poroelastic layered site. This analysis overcomes significant problems in wave scattering due to local soil conditions and dynamic soil-structure interaction. The Green's functions can be reduced to the case of an elastic layered site developed by Wolf in 1985. Parametric studies are then carried out through two example problems. 相似文献
10.
Sensitivity kernels for finite-frequency surface waves 总被引:1,自引:1,他引:1