全文获取类型
收费全文 | 467篇 |
免费 | 8篇 |
国内免费 | 5篇 |
专业分类
测绘学 | 38篇 |
大气科学 | 36篇 |
地球物理 | 101篇 |
地质学 | 209篇 |
海洋学 | 11篇 |
天文学 | 71篇 |
综合类 | 8篇 |
自然地理 | 6篇 |
出版年
2023年 | 3篇 |
2022年 | 12篇 |
2021年 | 7篇 |
2020年 | 7篇 |
2019年 | 10篇 |
2018年 | 40篇 |
2017年 | 32篇 |
2016年 | 24篇 |
2015年 | 17篇 |
2014年 | 30篇 |
2013年 | 42篇 |
2012年 | 23篇 |
2011年 | 19篇 |
2010年 | 15篇 |
2009年 | 24篇 |
2008年 | 19篇 |
2007年 | 19篇 |
2006年 | 18篇 |
2005年 | 11篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 7篇 |
2001年 | 2篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1970年 | 3篇 |
1969年 | 1篇 |
排序方式: 共有480条查询结果,搜索用时 171 毫秒
241.
Natural Hazards - The state of undivided Andhra Pradesh, India, spent around US$ 20 million per annum on drought relief programs during the period 1998–2008. However, till date, no long-term... 相似文献
242.
By use of the intrinsic representation based on unit vectors pointing along tangent, principal normal and bi-normal it is proved that steady circulation preserving magnetogeostrophic motions are the circular helical motion whose Lorentz surfaces are concentric circular cylinders. 相似文献
243.
Frequency of global axisymmetric oscillations of a perfect fluid disk rotating around a compact object is investigated by trial function method. A formula for the frequency of local radial oscillation is presented. 相似文献
244.
In this paper we present various classes of solutions for perfect fluid disks rotating around Schwarzschild black holes. We study the profiles of pressure, density and specific angular momentum and the formation of cusp-like structures at the inner edge of the disks. Using the trial function method, we calculate the frequency of the global axi-symmetric oscillations. We compare the results with those of the corresponding Newtonian calculations to find the general relativistic effects. 相似文献
245.
An empirical hyperbolic scale-dependent dispersion model, which predicts a linear growth of dispersivity close to the origin and the attainment of an asymptotic dispersivity at large distances, is presented for deterministic modelling of field-scale solute transport and the analysis of solute transport experiments. A simple relationship is derived between local dispersivity, which is used in numerical simulations of solute transport, and effective dispersivity, which is estimated from the analysis of tracer breakthrough curves. The scale-dependent dispersion model is used to interpret a field tracer experiment by nonlinear least-squares inversion of a numerical solution for unsaturated transport. Simultaneous inversion of concentration-time data from several sampling locations indicates a linear growth of the dispersion process over the scale of the experiment. These findings are consistent with the results of an earlier analysis based on the use of a constant dispersion coefficient model at each of the sampling depths. 相似文献
246.
247.
248.
Analytic expressions are derived for the minimum easterly and westerly jet strengths necessary for baroclinic instability, in terms of their half-widths and location. For this purpose the necessary condition for an internal jet is utilized and the jets and static stability are represented by simple mathematical functions. Dependency of the minimum jet strengths to their half-width and location are discussed. 相似文献
249.
250.
Non-self-similar isothermal flows behind weak cylindrical shock waves are investigated. The shock is assumed to be propagating in a medium at rest with uniform density permeated by a uniform transverse magnetic field. The electrical conductivity of the gas is infinite everywhere. The total energy of the disturbance is not constant but can be made to increase at a slow rate. A comparative study has been made between the results with an without a magnetic field. 相似文献