全文获取类型
收费全文 | 1904篇 |
免费 | 42篇 |
国内免费 | 23篇 |
专业分类
化学 | 1360篇 |
晶体学 | 13篇 |
力学 | 22篇 |
数学 | 240篇 |
物理学 | 334篇 |
出版年
2023年 | 9篇 |
2022年 | 9篇 |
2021年 | 13篇 |
2020年 | 16篇 |
2019年 | 29篇 |
2018年 | 23篇 |
2017年 | 23篇 |
2016年 | 46篇 |
2015年 | 39篇 |
2014年 | 50篇 |
2013年 | 97篇 |
2012年 | 137篇 |
2011年 | 127篇 |
2010年 | 78篇 |
2009年 | 74篇 |
2008年 | 91篇 |
2007年 | 111篇 |
2006年 | 119篇 |
2005年 | 102篇 |
2004年 | 80篇 |
2003年 | 73篇 |
2002年 | 72篇 |
2001年 | 27篇 |
2000年 | 27篇 |
1999年 | 30篇 |
1998年 | 22篇 |
1997年 | 30篇 |
1996年 | 32篇 |
1995年 | 21篇 |
1994年 | 16篇 |
1993年 | 11篇 |
1992年 | 19篇 |
1991年 | 17篇 |
1990年 | 18篇 |
1988年 | 14篇 |
1987年 | 11篇 |
1985年 | 14篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 18篇 |
1981年 | 13篇 |
1980年 | 15篇 |
1979年 | 15篇 |
1978年 | 13篇 |
1977年 | 22篇 |
1976年 | 18篇 |
1975年 | 16篇 |
1974年 | 12篇 |
1973年 | 11篇 |
1972年 | 8篇 |
排序方式: 共有1969条查询结果,搜索用时 93 毫秒
1.
2.
3.
The aim of this Note is to give explicit limit expressions, for diffusion equations involving a small parameter ε, describing both nonperiodic homogenization and reduction of dimension. We consider two kinds of reduction of dimension: the case of plates and the case of thin cylinders. In particular, we give the limit diffusion equation for stratified plates. This is completely explicit and requires no special assumption, except stratification. In the case of thin cylinders, the formulae are less explicit, but we also indicate some simple applications to fibered materials. To cite this article: B. Gustafsson, J. Mossino, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 977–982. 相似文献
4.
5.
6.
7.
After the laser was invented in 1960, a phase conjugation mirror has been respected to be the most fantastic one for the laser
resonator composition because it can compensate any distortions of the laser beams occurred by the many inhomogenuities of
the laser media and optical components. Among the many phase conjugation configurations, the stimulated Brillouin scattering
phase conjugation mirror is the most simple one and many researchers have tried to utilize it to develop high power/energy
laser systems. For realizing a high energy/power laser system the thermal problem is the most difficult to solve, and some
researchers suggested a beam combination technique to reduce the thermal load of the big laser media to many small sized ones.
To accomplish the beam combination using stimulated Brillouin scattering phase conjugation mirrors (SBS-PCMs), it is necessary
to lock/control the phases of the SBS-PCMs. And some researchers have developed several ways for it, but they can lock the
phases of a limited number of beams overlapped at the foci less than 5, or lock the phases by back-seeding technique but it
loses the phase conjugation characteristics. For realization of the laser fusion driver, it is necessary to combine more than
10 or 100 beams. And the authors have developed recently a new phase controlling/locking technique which is isolated and independent
totally from other beams and it can be applied to an unlimited number of beams in principle. 相似文献
8.
Kučinskaitė Agnė Pobłocka-Olech Loretta Krauze-Baranowska Mirosława Briedis Vitalis Savickas Aruñas Sznitowska Małgorzata 《平面色谱法杂志一现代薄层色谱法》2007,20(2):121-125
SPE and TLC have been used for qualitative and quantitative analysis of salidroside, rosavin, rosarin, and rosin in commercially available dry extracts from Rhodiola rosea roots. The best separation of all the compounds was achieved on silica gel TLC plates with ethyl acetate—methanol—water, 77 + 13 + 10 (v/v), as mobile phase. UV detection was performed at λ = 215 nm for salidroside and at λ= 245 nm for the rosavins (rosavin, rosarin, and rosin). Detection limits for salidroside and the rosavins were 90 ng and 60 ng per spot, respectively. Results from quantitative analysis confirmed the manufacturer’s declaration of the amounts of salidroside and the rosavins in the extracts.
相似文献9.
JPC – Journal of Planar Chromatography – Modern TLC - The flavonoid and triterpenoid soyasaponin content of the aerial parts of Desmodium adscendens from four geographical origins of... 相似文献
10.