全文获取类型
收费全文 | 1799篇 |
免费 | 50篇 |
国内免费 | 4篇 |
专业分类
化学 | 1284篇 |
晶体学 | 23篇 |
力学 | 16篇 |
数学 | 94篇 |
物理学 | 436篇 |
出版年
2023年 | 9篇 |
2022年 | 11篇 |
2021年 | 15篇 |
2020年 | 12篇 |
2019年 | 19篇 |
2018年 | 11篇 |
2017年 | 10篇 |
2016年 | 35篇 |
2015年 | 27篇 |
2014年 | 39篇 |
2013年 | 81篇 |
2012年 | 98篇 |
2011年 | 121篇 |
2010年 | 61篇 |
2009年 | 58篇 |
2008年 | 129篇 |
2007年 | 113篇 |
2006年 | 88篇 |
2005年 | 79篇 |
2004年 | 83篇 |
2003年 | 95篇 |
2002年 | 80篇 |
2001年 | 45篇 |
2000年 | 42篇 |
1999年 | 27篇 |
1998年 | 22篇 |
1997年 | 22篇 |
1996年 | 22篇 |
1995年 | 18篇 |
1994年 | 16篇 |
1993年 | 37篇 |
1992年 | 28篇 |
1991年 | 24篇 |
1990年 | 21篇 |
1989年 | 19篇 |
1988年 | 18篇 |
1987年 | 11篇 |
1986年 | 14篇 |
1985年 | 27篇 |
1984年 | 18篇 |
1983年 | 16篇 |
1981年 | 11篇 |
1980年 | 17篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 13篇 |
1976年 | 14篇 |
1975年 | 11篇 |
1974年 | 11篇 |
1973年 | 13篇 |
排序方式: 共有1853条查询结果,搜索用时 15 毫秒
1.
2.
The electrode reaction of decamethylferrocene (DMFc) dissolved in a thin layer of a room-temperature molten salt (RTMS), 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C8mimC1C1N) or 1-octyl-3-methylimidazolium bis(pentafluoroethylsulfonyl)imide (C8mimC2C2N), on a self-assembled monolayer-modified gold electrode is coupled with the ion transfer across the interface between the RTMS and the outer aqueous solution (W) to give a voltammogram whose shape resembles a voltammogram of a simple one-electron transfer process. The electroneutrality of the RTMS layer during the oxidation of DMFc to decamethylferricenium ion is maintained by the concomitant dissolution of C8mim+ ion from the RTMS phase to the W phase, and the reduction of decamethylferricenium ion to DMFc is accompanied by the transfer of either C1C1N- or C2C2N- from RTMS to W. The midpoint potential of the voltammogram varies with the concentration of the salt in the aqueous phase, C8mimCl or LiCnCnN (n = 1 or 2), in a Nernstian manner, showing that the phase-boundary potential between the RTMS and the W is controlled by the partition of these ions. Although the phase-boundary potential across the RTMS / W interface is Nernstian with respect to the ions common to both phases at the equilibrium, the polarization at the RTMS / W interface under current flow distorts the shape of the voltammograms, resulting in a wider peak separation in the voltammogram. 相似文献
3.
4.
5.
Statistical Inference for Stochastic Processes - 相似文献
6.
7.
8.
G. M. Luke L. P. Le B. J. Sternlieb Y. J. Uemura J. H. Brewer R. Kadono R. F. Kiefl S. R. Kreitzman T. M. Riseman C. E. Stronach M. Davis S. Uchida H. Takagi Y. Tokura Y. Hidaka T. Murakami E. A. Early J. T. Markert M. B. Maple C. L. Seaman 《Hyperfine Interactions》1991,63(1-4):311-317
We report muon spin relaxation/rotation measurements on sintered powder samples of Nd2−x
Ce
x
CuO4−y
and a large single crystal of Nd2CuO4−y
. We find an electronic phase diagram which is quite similar to that of hole-doped superconductors such as La2−x
Sr
x
CuO4−y
, although the doping of electrons into the system is less efficient in destroying the static moments on the copper spins.
Static magnetic order in Nd2CuO4−y
appears below about 250 K, and two spin reorientations are seen atT=75 K andT=35 K. Measurements of the magnetic field penetration depth have been unsuccessful due to the rare-earth paramagnetism of
these materials. 相似文献
9.
10.
Shigeru Katayama Mika Horiike Kazuyuki Hirao Naoto Tsutsumi 《Journal of Polymer Science.Polymer Physics》2002,40(24):2800-2806
We investigated the structures induced by an irradiation of a near‐infrared (NIR) femtosecond laser pulse in dye‐doped polymeric materials {poly(methyl methacrylate) (PMMA), thermoplastic epoxy resin (Epoxy), and a block copolymer of methyl methacrylate and ethyl acrylate‐butyl acrylate [p(MMA/EA‐BA) block copolymer]}. Dyes used were classified into two types—type 1 with absorption at 400 nm and type 2 with no absorption at 400 nm. The 400‐nm wavelength corresponds to the two‐photon absorption region by the irradiated NIR laser pulse at 800 nm. Type 1 dye‐doped PMMA and p(MMA/EA‐BA) block copolymer showed a peculiar dye additive effect for the structures induced by the line irradiation of a NIR femtosecond laser pulse. On the contrary, dye‐doped Epoxy did not exhibit a dye additive effect. The different results among PMMA, p(MMA/EA‐BA) block copolymer, and Epoxy matrix polymers are supposed to be related to the difference of electron‐acceptor properties. The mechanism of this type 1 dye‐additive‐effect phenomenon for PMMA and p(MMA/EA‐BA) block copolymer is discussed on the basis of two‐photon absorption of type 1 dye at 400 nm by the irradiation of a femtosecond laser pulse with 800 nm wavelength and the dissipation of the absorbed energy to the polymer matrix among various transition processes. Dyes with a low‐fluorescence quantum yield favored the formation of thicker grating structures. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2800–2806, 2002 相似文献