全文获取类型
收费全文 | 87篇 |
免费 | 32篇 |
国内免费 | 4篇 |
专业分类
化学 | 38篇 |
力学 | 3篇 |
综合类 | 1篇 |
数学 | 62篇 |
物理学 | 19篇 |
出版年
2019年 | 2篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 4篇 |
2012年 | 1篇 |
2011年 | 5篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 4篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2001年 | 2篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 5篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 6篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1967年 | 3篇 |
1966年 | 2篇 |
1964年 | 1篇 |
1958年 | 1篇 |
1943年 | 1篇 |
1936年 | 1篇 |
1934年 | 1篇 |
1930年 | 1篇 |
1913年 | 1篇 |
排序方式: 共有123条查询结果,搜索用时 15 毫秒
1.
2.
硅基材料是新一代高容量锂离子蓄电池负极材料的典型代表,近年来已成为理论研究和应用研究的热点.本文介绍了锂离子电池硅基负极材料的制备方法、电化学性能及其研究现状,分析了硅材料作为锂离子电池负极材料存在的问题;讨论了硅材料作为锂离子电池负极材料的研究前景.并指出若能克服目前存在问题,将有望成为新一代锂离子电池负极材料. 相似文献
3.
4.
5.
An experimental investigation has been undertaken to improve understanding of the role of the obturator and detonations in
the subdetonative ram accelerator starting process. Ram accelerator start experiments were conducted with various obturator
geometries to determine the obturator dynamics and assess its effect on the outcome of a start attempt. The obturator rapidly
decelerates upon entrance and then moves backwards. Reversal of direction occurs more rapidly after propellant ignition, for
less massive obturators, and solid geometries. Perforated geometries and decreasing obturator mass are less conducive to igniting
a given propellant, as evidenced by the flowfield and start attempt outcome data presented. Wave unstarts were observed to
occur with and without detonations, indicating more than one mechanism responsible for this type of start failure. Piston-initiated
detonation experiments were conducted by firing the obturators without the ram accelerator projectile. The piston experiments
identified the detonation limits for a wide range of propellants, but were found to not always be indicative of the upper
Mach number at which a ram accelerator can be successfully started. In some instances a successful start or wave fall-off
would occur at Mach numbers above which a piston alone detonated the propellant. Thus, the projectile can play a mitigating
role in detonation initiation and use of piston detonation limits to quantitatively define a detonation wave unstart limit
was not realized.
Received 6 April 1998 / Accepted 15 January 1999 相似文献
6.
Julius Schmidt Hans Rupe Fritz Pregl Horst Bruckner und Emil Abderhalden 《Fresenius' Journal of Analytical Chemistry》1930,81(8-9):323-324
Ohne Zusammenfassung 相似文献
7.
8.
9.
Liondas CA; Chrissoulidis DP 《The Quarterly Journal of Mechanics and Applied Mathematics》2007,60(3):275-287
This paper is intended to clarify a misunderstanding concerningthe source singularity of the electric Green's tensor for aperfectly conducting semi-infinite cone of circular cross-section.Tai's series expansion of the Green's tensor is known to lacka singular term at the source region. Jones has reconstructedthe solution to this problem and has pointed out the differencebetween his result and that of Tai. The aim of our paper isto demonstrate that, although Jones's closed-form solution iscorrect, there is a mistake in his comparison with Tai's seriessolution. We conclude that one of the two additional singularterms that Jones claims as missing from Tai's formula must beomitted. Besides, we compare Jones's closed-form solution withSmyshlyaev's solution to the very same problem. We concludethat the magnetic field expressions given by Jones and Smyshlyaevcoincide, but a singular term is missing from Smyshlyaev's expressionfor the electric field. 相似文献
10.
Goodman TNT; Micchelli CA; Rodriguez G; Seatzu S 《IMA Journal of Numerical Analysis》1998,18(3):331-354
It is shown that, under certain conditions, orthonormalizingthe positive integer shifts of an exponentially decaying functionon the half line by the Gram-Schmidt process leads to a limitingprofile given by orthonormalizing all their integer shifts onthe whole line. These results derive from properties of Choleskyfactorization of bi-infinite and semi-infinite matrices. Anexample is provided by the negative exponential function andconjectures are given, supported by numerical evidence, forthe Gaussian and Lorentz function. 相似文献