全文获取类型
| 收费全文 | 2499篇 |
| 免费 | 45篇 |
| 国内免费 | 1篇 |
专业分类
| 教育 | 1829篇 |
| 科学研究 | 139篇 |
| 各国文化 | 55篇 |
| 体育 | 213篇 |
| 文化理论 | 31篇 |
| 信息传播 | 278篇 |
出版年
| 2022年 | 17篇 |
| 2021年 | 21篇 |
| 2020年 | 39篇 |
| 2019年 | 78篇 |
| 2018年 | 84篇 |
| 2017年 | 97篇 |
| 2016年 | 86篇 |
| 2015年 | 54篇 |
| 2014年 | 86篇 |
| 2013年 | 609篇 |
| 2012年 | 58篇 |
| 2011年 | 63篇 |
| 2010年 | 52篇 |
| 2009年 | 54篇 |
| 2008年 | 65篇 |
| 2007年 | 65篇 |
| 2006年 | 54篇 |
| 2005年 | 48篇 |
| 2004年 | 45篇 |
| 2003年 | 46篇 |
| 2002年 | 50篇 |
| 2001年 | 46篇 |
| 2000年 | 60篇 |
| 1999年 | 43篇 |
| 1998年 | 28篇 |
| 1997年 | 21篇 |
| 1996年 | 21篇 |
| 1995年 | 21篇 |
| 1994年 | 20篇 |
| 1993年 | 29篇 |
| 1992年 | 36篇 |
| 1991年 | 28篇 |
| 1990年 | 31篇 |
| 1989年 | 19篇 |
| 1988年 | 21篇 |
| 1987年 | 24篇 |
| 1986年 | 19篇 |
| 1985年 | 25篇 |
| 1984年 | 16篇 |
| 1983年 | 10篇 |
| 1982年 | 15篇 |
| 1981年 | 21篇 |
| 1980年 | 14篇 |
| 1979年 | 19篇 |
| 1978年 | 17篇 |
| 1977年 | 11篇 |
| 1976年 | 13篇 |
| 1975年 | 10篇 |
| 1968年 | 8篇 |
| 1889年 | 9篇 |
排序方式： 共有2545条查询结果，搜索用时 824 毫秒
101.
102.
103.
Describing the plastic deformation of aluminium softball bats 总被引：1，自引：1，他引：0
Hollow aluminium bats were introduced over 30 years ago to provide improved durability over wooden bats. Since their introduction,
however, interest in hollow bats has focused almost exclusively around their hitting performance. The aim of this study was
to take advantage of the progress that has been made in predicting bat performance using finite elements and apply it to describe
bat durability. Accordingly, the plastic deformation from a ball impact of a single-wall aluminum bat was numerically modelled.
The bat deformation from the finite-element analysis was then compared with experiment using a high-speed bat test machine.
The ball was modelled as an isotropic, homogeneous, viscoelastic sphere. The viscoelastic parameters of the ball model were
found from instrumented, high-speed, rigid-wall ball impacts. The rigid-wall ball impacts were modelled numerically and showed
good agreement with the experimentally obtained response. The strain response of the combined bat-ball model was verified
with a strain-gauged bat at intermediate ball impact speeds in the elastic range. The strain response of the bat-ball model
exhibited positive correlation with the experimental measurements. High-speed bat-ball impacts were performed experimentally
and simulated numerically at increasing impact speeds which induced correspondingly increased dent sizes in the bat. The plastic
deformation from the numerical model found good agreement with experiment provided the aluminium work hardening and strain
rate effects were appropriately described. The inclusion of strain rate effects was shown to have a significant effect on
the bat deformations produced in the finite-element simulations. They also helped explain the existence of high bat stresses
found in many performance models. 相似文献
104.
105.
106.
107.
108.
109.
110.