全文获取类型
收费全文 | 4609篇 |
免费 | 613篇 |
国内免费 | 418篇 |
专业分类
化学 | 1205篇 |
晶体学 | 46篇 |
力学 | 1619篇 |
综合类 | 81篇 |
数学 | 1152篇 |
物理学 | 1537篇 |
出版年
2024年 | 13篇 |
2023年 | 33篇 |
2022年 | 80篇 |
2021年 | 118篇 |
2020年 | 142篇 |
2019年 | 99篇 |
2018年 | 125篇 |
2017年 | 154篇 |
2016年 | 202篇 |
2015年 | 137篇 |
2014年 | 238篇 |
2013年 | 374篇 |
2012年 | 259篇 |
2011年 | 250篇 |
2010年 | 201篇 |
2009年 | 261篇 |
2008年 | 273篇 |
2007年 | 284篇 |
2006年 | 289篇 |
2005年 | 270篇 |
2004年 | 213篇 |
2003年 | 210篇 |
2002年 | 150篇 |
2001年 | 120篇 |
2000年 | 135篇 |
1999年 | 146篇 |
1998年 | 100篇 |
1997年 | 119篇 |
1996年 | 100篇 |
1995年 | 87篇 |
1994年 | 71篇 |
1993年 | 41篇 |
1992年 | 55篇 |
1991年 | 57篇 |
1990年 | 36篇 |
1989年 | 21篇 |
1988年 | 39篇 |
1987年 | 27篇 |
1986年 | 20篇 |
1985年 | 23篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1982年 | 13篇 |
1981年 | 9篇 |
1980年 | 2篇 |
1979年 | 10篇 |
1978年 | 7篇 |
1977年 | 4篇 |
1971年 | 1篇 |
1957年 | 2篇 |
排序方式: 共有5640条查询结果,搜索用时 31 毫秒
1.
Cavitation erosion is caused in solids exposed to strong pressure waves developing in an adjacent fluid field. The knowledge of the transient distribution of stresses in the solid is important to understand the cause of damaging by comparisons with breaking points of the material. The modeling of this problem requires the coupling of the models for the fluid and the solid. For this purpose, we use a strategy based on the solution of coupled Riemann problems that has been originally developed for the coupling of 2 fluids. This concept is exemplified for the coupling of a linear elastic structure with an ideal gas. The coupling procedure relies on the solution of a nonlinear equation. Existence and uniqueness of the solution is proven. The coupling conditions are validated by means of quasi‐1D problems for which an explicit solution can be determined. For a more realistic scenario, a 2D application is considered where in a compressible single fluid, a hot gas bubble at low pressure collapses in a cold gas at high pressure near an adjacent structure. 相似文献
2.
3.
4.
许多实验对用CsI(Tl)闪烁晶体作为探测器来寻找和探测暗物质的可行性进行了研究.本工作利用8MeV单能中子轰击CsI(Tl)晶体探测器来研究Cs核和I核的QuenchingFactor.在数据处理中,运用脉冲形状甄别(PSD)方法来分辨反冲核信号和本底信号.实验结果表明,在7keV到132keV的能区中,Quench ingFactor随着反冲核能量的减少而增加.在探测暗物质的实验中,这一性质对于CsI(Tl)晶体探测器获得较低的能量阈值是很有利的. 相似文献
5.
6.
GU Bai-Ping REN Zhong-Zhou 《理论物理通讯》2005,44(2):337-342
The Dirac optical potential for p-^14 Be elastic scattering is evaluated by the relativistic impulse approximation. Each of the real part and the imaginary part of the potential shows a pronounced “long tail” for the proton elastic scattering from halo nucleus ^14Be compared with the potentials for proton scattering from its adjacent nuclei ^12C and ^16O, which do not have halo structures.This kind of “long tail” phenomenon suggests another signature for halo nuclei. 相似文献
7.
对于超细长弹性杆静力学的Kirchhoff方程,用动力学的概念和方法研究其常值特解 和稳定性问题.计算了Kirchhoff方程相对固定坐标系、截面主轴坐标系以及中心线Frenet 坐标系的常值特解,进行了Kirchhoff动力学比拟,用一次近似理论分别讨论了它们的Lyapu nov稳定性,导出了若干稳定性判据,并在参数平面上绘出了稳定域.
关键词:
超细长弹性杆
Kirchhoff方程
常值特解
Lyapunov稳定性 相似文献
8.
A theorem of Birkhoff‐Frink asserts that every algebraic closure operator on an ordinary set arises, from some algebraic structure on the set, as the corresponding generated subalgebra operator. However, for many‐sorted sets, i.e., indexed families of sets, such a theorem is not longer true without qualification. We characterize the corresponding many‐sorted closure operators as precisely the uniform algebraic operators. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
9.
Two groups of 10 speech-language pathology graduate students were each given 7 weeks of singing lessons to determine whether voice lessons could have an effect on their clinical and perceptual skills. Pre-, mid-, and posttests to measure various skills were designed and implemented. With use of paired sample statistical testing, statistically significant results were obtained. In addition, the subjective responses of the students show that the lessons were effective in improving pitch perception, breath control, and legato production or easy onset. This study supports efforts to integrate curricula in vocal performance and speech-language pathology. 相似文献
10.