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21.
22.
W. Kuch 《Applied Physics A: Materials Science & Processing》2003,76(5):665-671
Photoelectron emission microscopy in connection with magnetic circular dichroism in soft X-ray absorption can be used for
the microscopic imaging of magnetic domains in layered thin film structures consisting of several magnetic layers. Due to
the element-selectivity of the method, the different magnetic layers in such a structure can be imaged separately, provided
that they contain different elements. This has been applied for the investigation of Co/Cu/Ni trilayers, epitaxially grown
on Cu (001). The magnetic coupling between the Co and Ni layers can be directly visualized from comparing layer-resolved magnetic
domain images of both layers. As a consequence of the competition between the anisotropy energies of the two magnetic layers
and the magnetic coupling energy, spin-reorientation transitions between collinear and non-collinear magnetic configurations
are observed. Apart from this globally observable magnetic interlayer coupling a micromagnetic coupling mechanism is also
evident from the layer-resolved domain images. It is caused by magnetostatic interaction of local stray fields from domain
walls.
Received: 22 August 2002 / Accepted: 2 October 2002 / Published online: 5 February 2003
RID="*"
ID="*"Corresponding author. Fax: +49-345/5511-223, E-mail: kuch@mpi-halle.de 相似文献
23.
R. Frömter H.P. Oepen J. Kirschner 《Applied Physics A: Materials Science & Processing》2003,76(6):869-871
The basics of the scanning electron microscope with polarization analysis are briefly reviewed, emphasizing the achievable
magnetic resolution and image contrast. The design of an optimized spin-polarization detector based on the well-established
LEED scattering principle is presented. Results of first tests are reported.
Received: 2 September 2002 / Accepted: 2 September 2002 / Published online: 5 March 2003
RID="*"
ID="*"Corresponding author. Fax: +49-40/42838-6368, E-mail: RFroemte@PHYSnet.Uni-Hamburg.de 相似文献
24.
C. Teichert 《Applied Physics A: Materials Science & Processing》2003,76(5):653-664
Spontaneous pattern formation during epitaxial growth or ion erosion of semiconductor wafers offers an elegant route towards
large-area nanostructured surfaces. In homoepitaxy, kinetics may result in rather uniform three-dimensional islands. In the
case of semiconductor heteroepitaxy, strain relief leads to the formation of nanofaceted three-dimensional crystallites, which
may self-organize into quasiperiodic arrays. By tuning substrate miscut and film thickness, or growing superlattices, a variety
of patterns with different symmetries can be obtained, as will be summarized for the model system of SiGe on Si(001). Since
these self-organized nanostructure arrays cover the entire wafer on which they are grown, they can serve as large-area nanopatterned
substrates for subsequent deposition of magnetic thin films. It will be demonstrated that such templates allow the study of
correlations between magnetic and chemical interfacial roughness, as well as the influence of pattern symmetry on the magnetic
anisotropy of thin Co films. Furthermore, shadow deposition of magnetic material onto specially faceted nanostructure arrays
allows the fabrication of nanomagnet arrays and the study of their magnetic properties.
Received: 31 July 2002 / Accepted: 2 October 2002 / Published online: 5 February 2003
RID="*"
ID="*"Corresponding author. Fax: +43-3842/402-760, E-mail: teichert@unileoben.ac.at 相似文献
25.
A. Krasyuk A. Oelsner S.A. Nepijko A. Kuksov C.M. Schneider G. Schönhense 《Applied Physics A: Materials Science & Processing》2003,76(6):863-868
Owing to its parallel image acquisition, photoemission electron microscopy is well suited for real-time observation of fast
processes on surfaces. Pulsed excitation sources like synchrotron radiation or lasers, fast electric pulsers for the study
of magnetic switching, and/or time-resolved detection can be utilised. A standard approach also being used in light optical
imaging is stroboscopic illumination of a periodic (or quasi-periodic) process. Using this technique, the time dependence
of the magnetic field in a pulsed microstrip line has been imaged in real time exploiting Lorentz-type contrast. Similarly,
the corresponding field-induced changes in the magnetisation of cobalt microstructures deposited on the microstrip line have
been observed exploiting magnetic X-ray circular dichroism as a contrast mechanism. The experiment has been performed at the
UE 56/1-PGM at BESSY II (Berlin) in the single-bunch mode.
Received: 2 September 2002 / Accepted: 2 September 2002 / Published online: 5 March 2003
RID="*"
ID="*"Corresponding author. Fax: +49-6131/392-3807, E-mail: krasyuk@mail.uni-mainz.de 相似文献
26.
A. Borowiec M. MacKenzie G.C. Weatherly H.K. Haugen 《Applied Physics A: Materials Science & Processing》2003,76(2):201-207
The final state of the material resulting from laser irradiation of silicon using 130 fs pulses at 790 nm was studied using
a number of techniques including scanning and transmission electron microscopies, as well as atomic force microscopy. Structural
details and the level of damage to the nearby solid following irradiation were characterized and are discussed in the context
of recent dynamical studies.
Received: 28 September 2001 / Accepted: 3 March 2002 / Published online: 19 July 2002
RID="*"
ID="*"Department of Engineering Physics, McMaster University, Hamilton, Ontario, L8S 4M1, Canada
RID="**"
ID="**"Corresponding author. Fax: +1-905/521-2773, E-mail: borowia@mcmaster.ca
RID="***"
ID="***"Present address: Department of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
RID="****"
ID="****"Department of Materials Science and the CEMD, McMaster University, Hamilton, Ontario, L8S 4M1, Canada
RID="*****"
ID="*****"Departments of Engineering Physics, and Physics and Astronomy, and the CEMD, McMaster University, Hamilton, Ontario,
L8S 4M1, Canada 相似文献
27.
Structural characterization of a new lipid/DNA complex showing a selective transfection efficiency in ovarian cancer cells 总被引:5,自引:0,他引:5
Caracciolo G Pozzi D Caminiti R Congiu Castellano A 《The European physical journal. E, Soft matter》2003,10(4):331-336
We investigated, for the first time, by using Energy Dispersive X-ray Diffraction, the structure of a new ternary cationic
liposome formulated with dioleoyl trimethylammonium propane (DOTAP), 1,2-dioleoyl-3-phosphatidylethanolamine (DOPE) and cholesterol
(Chol) (DDC) which has been recently found to have a selective high gene transfer ability in ovarian cancer cells. Our structural
results provide a further experimental support to the widely accepted statement that there is not a simple and direct correlation
between structure and transfection efficiency and that the factors controlling cationic lipid/DNA (CL-DNA) complexes-mediated
gene transfer depend not only on the formulations of the cationic liposomes and their thermodynamic phase, but also significantly
on the cell properties.
Received: 28 October 2002 / Accepted: 21 March 2003 / Published online: 15 April 2003
RID="a"
ID="a"e-mail: a.congiu@caspur.it 相似文献
28.
K.-M. Källman M. Brenner V.Z. Goldberg T. Lönnroth P. Manngård A.E. Pakhomov V.V. Pankratov 《The European Physical Journal A - Hadrons and Nuclei》2003,16(2):159-169
The excitation function and angular distributions of elastic α-particle scattering on 28Si have been measured in the laboratory energy range 6-28 MeV using a backscattering technique on a thick target, yielding
a continuous energy distribution. More than 200 narrow states are observed, with widths in the range ∼ 30-100 keV at excitation
energies E
* = 13-32 MeV. Angular distributions at backward angles were measured, and angular momentum values of more than 83 states have
been deduced. The analysis gives spin-parities J
π, α-partial widths Γα and reduced widths of the narrow high-lying resonant states in 32S. The experimentally observed states display both the negative- and the positive-parity rotational-like sequences with seemingly
no parity splitting, a finding which is at variance with most potential-model predictions. The deduced effective moment of
inertia indicates a more extended structure than the ground-state configuration. The observed strength of each ℓ-value is
analyzed in terms of an underlying split doorway state of Lorentzian form, which yields an interpretation as fragmented rotational
α + 28Si states.
Received: 26 June 2000 / Accepted: 16 September 2002 / Published online: 4 February 2003
RID="a"
ID="a"e-mail: kkallman@abo.fi
RID="b"
ID="b"Present address: Swedish Polytechnic, FIN-65200 Vasa, Finland.
Communicated by D. Guerreau 相似文献
29.
B. Eckhardt R. Pandit 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(3):373-378
We consider the effects of a shear on velocity fluctuations in a flow. The shear gives rise to a transient amplification that
not only influences the amplitude of perturbations but also their time correlations. We show that, in the presence of white
noise, time correlations of transversal velocity components are exponential and that correlations of the longitudinal components
are exponential with an algebraic prefactor. Cross correlations between transversal and downstream components are strongly
asymmetric and provide a clear indication of non-normal amplification. We suggest experimental tests of our predictions.
Received 26 February 2002 / Received in final form 11 March 2003 Published online 20 June 2003
RID="a"
ID="a"e-mail: bruno.eckhardt@physik.uni-marburg.de
RID="b"
ID="b"Also at: Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India 相似文献
30.
Electronic properties of both Pb and S vacancy defects in PbS(1^-00) have been studied using the first-principles density functional theory (DFT) calculations with the plane-wave pseudopotentials. It is found that the density of states (DOS) near the top of the valence band and the bottom of the conduction band is significantly modified by these defects. Our calculation indicates that in the case of S vacancy defects the Fermi energy shifts to the conduction band making it as an n-type PbS (donor). However, in the case of Pb vacancy, because of the appreciable change of the DOS, the system acts as a p-type PbS (accepter). In addition, the structural relaxation shows that the defect leads to outward relaxation of the nearest-neighbouring atoms and inward relaxation of the next-nearest neighbouring atoms. 相似文献