全文获取类型
收费全文 | 88篇 |
免费 | 11篇 |
国内免费 | 16篇 |
专业分类
测绘学 | 2篇 |
大气科学 | 2篇 |
地球物理 | 41篇 |
地质学 | 52篇 |
海洋学 | 13篇 |
自然地理 | 5篇 |
出版年
2024年 | 2篇 |
2023年 | 1篇 |
2021年 | 1篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 1篇 |
2015年 | 2篇 |
2014年 | 9篇 |
2013年 | 8篇 |
2012年 | 6篇 |
2011年 | 9篇 |
2010年 | 9篇 |
2009年 | 6篇 |
2008年 | 10篇 |
2007年 | 12篇 |
2006年 | 9篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1996年 | 1篇 |
排序方式: 共有115条查询结果,搜索用时 0 毫秒
41.
An analytical solution for the local suspended sediment concentration profile in tidal sea region 总被引:1,自引:0,他引:1
Kyung Tae Jung Jae Youll Jin Hyoun-Woo Kang Ho Jin Lee 《Estuarine, Coastal and Shelf Science》2004,61(4):657-667
The time-averaged and oscillatory solutions of the one-dimensional vertical (1DV) advection–diffusion equation for the suspended sediment have been derived analytically in a tidal sea region of finite water depth. The basic equation assumes constant eddy diffusivity and settling velocity. No net flux condition is set at the sea surface, while a boundary condition with the erosion rate and depositional velocity is prescribed at the sea bottom. The time-averaged solution has been derived in a straightforward manner, while the advection–diffusion equation governing the oscillatory concentration has been first transformed to a simple diffusion equation and then solved using the Galerkin-eigenfunction method. The former is given in a closed form, while the latter is presented in a series solution.A set of calculations has been performed to examine the change in the vertical structure as well as magnitude of the concentration response function. A possible use of the solution to make an estimate of the erosion rate at the sea bottom based on the concentration information at the sea surface is discussed. 相似文献
42.
43.
For accurate prediction of the deformation of cable in the towed system, a new finite element model is presented that provides a representation of both the bending and torsional effects. In this paper, the cubic spline interpolation function is applied as the trial solution. By using a weighted residual approach, the discretized motion equations for the new finite element model are developed. The model is calculated with the computation program complier by Matlab. Several numerical examples are presented to illustrate the numerical schemes. The results of numerical simulation are stable and valid, and consistent with the mechanical properties of the cable. The model can be applied to kinematics analysis and the design of ocean cable, such as mooring lines, towing, and ROV umbilical cables. 相似文献
44.
间断有限元(Discontinuous Galerkin:DG)方法具有低数值频散、网格剖分灵活、能模拟地震波在复杂介质中传播等优点.因此,本文将一种新的DG方法推广到双相和黏弹性等复杂介质的地震波场模拟,发展了求解Biot弹性波方程和D'Alembert介质波动方程的DG方法.首先通过引入辅助变量将Biot双相介质弹性波方程和D'Alembert介质波动方程转化为关于时间-空间的一阶偏微分方程组,然后对该方程组进行DG空间离散,得到半离散化的常微分方程组.最后,对此常微分方程组,应用加权的Runge-Kutta格式进行时间推进计算.数值结果表明,DG方法可以有效地求解Biot双相介质弹性波方程和D'Alembert介质波动方程,并能很好地压制因离散求解波动方程而产生的数值频散,获得清晰的各种地震波震相.
相似文献45.
In this paper, we examine heuristically the reasons for locking in poroelasticity. As a first step, we first reexamine the
problem of locking in linear elasticity. From this, we discover how the problem arises in the poroelasticity setting and how
the problem might be overcome. 相似文献
46.
A space-time discontinuous Galerkin finite element method is proposed and applied to a convection-dominant single-phase flow
problem in porous media. The numerical scheme is based on a coupled space-time finite element discretization allowing for
discontinuous approximations in space and in time. The continuities on the element interfaces are weakly enforced by the flux
treatments, so that no extra penalty factor has to be determined. The resulting space-time formulation possesses the advantage
of capturing the steep concentration front with sharp gradients efficiently. The stability and reliability of the proposed
approach is demonstrated by numerical experiments.
The author is grateful to the DFG (German Science Foundation—Deutsche Forschungsgemeinschaft) for the financial support under
the grant number Di 430/4-2. 相似文献
47.
48.
黑龙洞泉域地下水流数值模拟与预测 总被引:2,自引:0,他引:2
为了对黑龙洞泉域水资源进行评价, 通过对地质条件、水位观测资料的深入研究, 以水均衡原理、地下水渗流理论为基础, 建立了黑龙洞泉域地下水渗流数值模型.以灰色序列预测模型为辅助手段, 结合历年的降水规律, 对未来现状开采条件下的年均降水量、地下水流场、水位及泉流量进行了不同保证率条件下的预测, 若2010年为丰水年(保证率20%)、平水年(保证率50%)、枯水年(保证率75%), 黑龙洞泉汛期地下水位标高分别为超过130m、达到130m、低于130m, 汛期泉流量分别为超过10m3/s、7m3/s、5m3/s.计算结果有利于指导黑龙洞泉域地下水资源的管理和开发利用. 相似文献
49.
This paper describes the numerical results for the COUPLEX benchmark obtained with the simulation software UG using vertex centered finite volume and higher order discontinuous Galerkin schemes. Multigrid solvers on unstructured grids, local mesh refinement and parallel computation are employed to yield very accurate solutions. Since the full range of results required in the benchmarks is too large to be displayed in this paper we focus on the comparison of discretization schemes, assessment of numerical errors and the presentation of parallel computations. 相似文献
50.
基于渗流和管流耦合的管涌数值模拟 总被引:6,自引:0,他引:6
堤坝地基的渗透变形过程实际上是“土中水”转变为“水中土”的过程。在渗透变形发生的集中管涌通道区域,采用常规渗流分析理论,单纯增大管涌通道渗透系数的方法是不太合适的。在未发生渗透变形的区域,用常规渗流理论计算;在管涌通道区域,用管流理论,公共边界上两者之间水头相等、流量大小相等且方向相反,能够较好符合渗透变形的发展规律。为了适应计算过程中内部边界条件不断变化的特点,采用无网格法伽辽金法(element free Galerkin method,EFG)对渗流场进行计算。算例计算表明,这种渗流-管流耦合的方法能够模拟管涌通道绕过防渗墙等复杂的发展过程。 相似文献