全文获取类型
收费全文 | 282篇 |
免费 | 74篇 |
国内免费 | 20篇 |
专业分类
化学 | 71篇 |
晶体学 | 5篇 |
力学 | 70篇 |
综合类 | 12篇 |
数学 | 33篇 |
物理学 | 185篇 |
出版年
2023年 | 4篇 |
2022年 | 21篇 |
2021年 | 14篇 |
2020年 | 14篇 |
2019年 | 6篇 |
2018年 | 9篇 |
2017年 | 18篇 |
2016年 | 10篇 |
2015年 | 13篇 |
2014年 | 16篇 |
2013年 | 17篇 |
2012年 | 17篇 |
2011年 | 21篇 |
2010年 | 21篇 |
2009年 | 15篇 |
2008年 | 21篇 |
2007年 | 12篇 |
2006年 | 16篇 |
2005年 | 21篇 |
2004年 | 10篇 |
2003年 | 9篇 |
2002年 | 19篇 |
2001年 | 8篇 |
2000年 | 10篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1990年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有376条查询结果,搜索用时 15 毫秒
21.
22.
将基于应变软化玻璃状高分子材料微观特征建立的BPA8-链分子网络模型引入UpdatingLagrange有限元方法,建立了适于变形局部化分析的大变形弹塑性有限元驱动应力法.在此基础上,数值模拟了初始各向同性高分子材料平面应变拉伸变形局部化的传播过程.探讨了BPA模型对具有加工硬化特性的结晶性高分子材料变形分析的适应性;分析了局部化传播过程中颈缩截面的非均匀应力三轴效应;最后,讨论了网格尺寸以及初始几何不均匀性对颈缩扩散以及应力三轴效应的影响 相似文献
23.
24.
25.
应用油藏工程方法,综合考虑驱替压力梯度和启动压力梯度的影响对薄差储层有效驱替理论进行研究.根据不等产量一源一汇驱替压力梯度公式,分别得到地层压力、注入压力、井底流压以及井距变化时的驱替压力梯度图版,并分析其变化规律;根据岩心水动力实验结果,建立启动压力梯度与渗透率的关系,分析有效驱动不同渗透率的储层所需要的驱替压力梯度临界值.研究表明:驱替压力梯度大于最大启动压力梯度是薄差储层有效驱替的必要条件;小井距是薄差层有效驱动的最优选择;可以通过措施和注采压力系统调整达到驱替压力梯度高于最大启动压力梯度的目的,从而有效驱动薄差储层.研究对薄差储层开采具有重要的指导意义,并在矿场试验中得到了有效论证. 相似文献
26.
27.
28.
Numerical investigation of hydroplaning characteristics of three-dimensional patterned tire 总被引:6,自引:0,他引:6
J.R. Cho H.W. Lee J.S. Sohn G.J. Kim J.S. Woo 《European Journal of Mechanics - A/Solids》2006,25(6):914-926
Hydroplaning characteristics of patterned tire on wet road are investigated by making use of finite volume and finite element methods. A detailed 3-D patterned tire model is constructed by our in-house modeling program and the rainwater flow is considered as incompressible and inviscid. Meanwhile, the fluid–structure interaction between the highly complicated tire tread and the rainwater flow is effectively treated by the general coupling method. Through the numerical experiments, the rainwater flow drained through tire grooves, hydrodynamic pressure and contact force are investigated and compared with those of the three-grooved tire model. 相似文献
29.
Paul Hölscher 《Transport in Porous Media》1992,9(1-2):73-84
The behaviour of the soil under a dynamically loaded pile toe is studied. The soil is modelled as a fluid saturated porous continuum. The constitutive behaviour of the solid skeleton is described by the elasto-plastic model of Drücker-Prager. The wave propagation is simulated with a dynamical finite-element program.A two-phase model of soil gives useful information about effective stress and pore pressure in the soil. In saturated soil the main wave under the pile toe propagates more downards than in dry soil, due to the higher compressional stiffness in saturated soil. The plastic zone under the pile toe propagates with the velocity of the fast compressional wave. The pore fluid influences the plasticity strongly and can be expected to affect pile driving too.The distribution of effective stress and pore pressure under the pile toe depends on the permeability of the soil and cannot be calculated uniquely from a single-phase calculation. Therefore, a nonlinear soil cannot be modelled correctly as a conventional single-phase material. 相似文献
30.
Mark Lusk 《Journal of Elasticity》1996,44(3):271-284
A purely mechanical, sharp interface model is developed to consider curved interfaces that have been observed between martensite phase variants. The approach is based on a theory of small strains as distinct from small displacement gradients. It admits a realistic characterization of each phase with standard elasticity tensors and allows for inhomogeneous states of strain within each phase including inhomogeneous, finite rotations. The model indicates that any signficant interface curvature must be due to material rotation because interfaces cannot be finitely curved with respect to the material lattice. It is also found that the interface driving traction is not influenced by local lattice rotations unless inertia affects the reaction. 相似文献