全文获取类型
收费全文 | 99篇 |
免费 | 1篇 |
专业分类
化学 | 39篇 |
数学 | 15篇 |
物理学 | 46篇 |
出版年
2017年 | 3篇 |
2016年 | 1篇 |
2015年 | 2篇 |
2013年 | 4篇 |
2012年 | 6篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 3篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 7篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1931年 | 1篇 |
1928年 | 2篇 |
1923年 | 1篇 |
排序方式: 共有100条查询结果,搜索用时 15 毫秒
11.
Self-injection length in La0.7Ca0.3MnO3-YBa2Cu3O7-δ ferromagnet-superconductor multilayer thin films
We have carried out extensive studies on the self-injection problem in barrierless heterojunctions between La0.7Ca0.3MnO3 (LCMO) and YBa2Cu3O7-δ (YBCO) thin films. The heterojunctions were formed in situ by sequentially growing LCMO and YBCO films on 〈100〉 LaAlO3 (LAO) substrate using a pulsed laser deposition (PLD) system. YBCO micro-bridges with 64 μm width were patterned both on
the LAO (control) and LCMO side of the substrate. Critical current, I
c, was measured at 77 K on both the control side as well as the LCMO side for different YBCO film thickness. It was observed
that while the control side showed a J
c of ∼ 2 × 106 A/cm2, the LCMO side showed about half the value for the same thickness (1800 ?). The difference in J
c indicates that a certain thickness of YBCO has become ‘effectively’ normal due to self-injection. From the measurement of
J
c at two different thicknesses (1800 ? and 1500 ?) of YBCO films both on the LAO as well as the LCMO side, the value of self-injection
length (at 77 K) was estimated to be ∼ 900 ?. To the authors’ best knowledge, this is the first time that self-injection length
has been quantified. A control experiment carried out with LaNiO3 deposited by PLD on YBCO did not show any evidence of self-injection. 相似文献
12.
AM Jayannavar 《Pramana》2002,58(2):173-181
We present a simple model of transmission across a metallic mesoscopic ring. In one of its arm an electron interacts with
a single magnetic impurity via an exchange coupling. We show that entanglement between electron and spin impurity states leads
to reduction of Aharonov-Bohm oscillations in the transmission coefficient. The spin-conductance is asymmetric in the flux
reversal as opposed to the two-probe electrical conductance which is symmetric. In the same model, in contradiction to the
naive expectation of a current magnification effect, we observe enhancement as well as suppression of this effect depending
on the system parameters. The limitations of this model to the general notion of dephasing or decoherence in quantum systems
are pointed out. 相似文献
13.
Allan J Macleod 《Journal of Computational and Applied Mathematics》1982,8(4):275-277
Eight different algorithms for polynomial interpolation are compared with respect to stability and computational efficiency. Large differences in performance are described and certain methods are shown to be very undesirable. 相似文献
14.
15.
Annulation of primary amines to piperazines and diazaspirocycles utilizing alpha-methyl benzyl resin
Macleod C Martinez-Teipel BI Barker WM Dolle RE 《Journal of combinatorial chemistry》2006,8(1):132-140
The microwave-assisted solid-phase synthesis of piperazines, 3,9-diazaspiro[5.5]undecanes and 2,9-diazaspiro[5.5]undecanes is reported. The synthesis relies on the direct annulation of primary amines with resin-bound bismesylates. Critical to the success of this chemistry was the development of alpha-methyl benzyl carbamate resin linker. This resin permits the cleavage of the heterocycles under mildly acidic conditions, free of contaminating linker-derived N-alkylated byproducts. 相似文献
16.
Allan J. Macleod 《International Journal of Mathematical Education in Science & Technology》2013,44(6):691-696
A model for the pH of a mixture of a monoprotic acid and its associated salt leads to a cubic equation. This equation is shown to have real roots — one positive and two negative. The exact theory for cubic equations provides a simple expression for the positive root. Due to rounding errors the use of this formula can give poor results, so the use of Newton‐Raphson is considered. 相似文献
17.
The leading asymptotic term for the function that counts theeigenvalues of the Stokes operator is determined for fairlygeneral underlying bounded domains. Moreover, the remainderis estimated in terms of the fractality of the boundary of thedomain. The results obtained resemble corresponding ones forthe Dirichlet Laplacian. 1991 Mathematics Subject Classification:35P20. 相似文献
18.
19.
T. Bäck B. Cederwall R. Wyss A. Johnson J. Cederkäll M. Devlin J. Elson D.R. LaFosse F. Lerma D.G. Sarantites R.M. Clark P. Fallon I.Y. Lee A.O. Macchiavelli R.W. Macleod 《The European Physical Journal A - Hadrons and Nuclei》1999,6(4):391-397
High-spin states in 88Mo were studied using the Gammasphere germanium detector array in conjunction with the Microball CsI(Tl) charged-particle
detector system. Three γ-ray cascades with dynamic moments of inertia showing similar characteristics to superdeformed rotational
bands observed in the neighbouring A= 80 region have been identified and assigned to the nucleus 88Mo. The quadrupole moment of the strongest band, deduced by the Residual Doppler Shift Method, corresponds to a quadrupole
deformation of β2≈ 0.6. This confirms the superdeformed nature of this band. The experimental data are interpreted in the framework of total
routhian surface calculations. All three bands are assigned to two-quasi-particle proton configurations at superdeformed shape.
Received: 20 May 1999 / Revised version: 25 August 1999 相似文献
20.
KM Varier AM Vinodkumar NVSV Prasad PV Madhusudhana Rao DL Sastry Lagy T Baby MC Radhakrishna NG Puttaswamy JJ Das P Sugathan N Madhavan AK Sinha DO Kataria 《Pramana》1999,53(3):529-533
Large enhancements have been observed in the sub-barrier fusion cross sections for Ti+Ni systems in our previous studies.
Coupled channel calculations incorporating couplings to 2+ and 3− states failed to explain these enhancements completely. A possibilty of transfer channels contributing to the residual enhancements
had been suggested. In order to investigate the role of relevant transfer channels, measurements of one- and two-nucleon transfer
were carried out for 46,48Ti+61Ni systems. The present paper gives the results of these studies. 相似文献