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71.
S. Gandolfi F. Pederiva S. a Beccara 《The European Physical Journal A - Hadrons and Nuclei》2008,35(2):207-211
We computed ground-state energies of calcium isotopes from 42Ca to 48Ca by means of the Auxiliary Field Diffusion Monte Carlo (AFDMC) method. Calculations were performed by replacing the 40Ca core with a mean-field self-consistent potential computed using the Skyrme interaction. The energy of the external neutrons
is calculated by projecting the ground state from a wave function built with the single-particle orbitals computed in the
self-consistent external potential. The shells considered were the 1F
7/2 and the 1F
5/2 . The Hamiltonian employed is semi-realistic and includes tensor, spin-orbit and three-body forces. While absolute binding
energies are too deep if compared with experimental data, the differences between the energies for nearly all isotopes are
in very good agreement with the experimental data. 相似文献
72.
M. Mukherjee D. Beck K. Blaum G. Bollen J. Dilling S. George F. Herfurth A. Herlert A. Kellerbauer H. -J. Kluge S. Schwarz L. Schweikhard C. Yazidjian 《The European Physical Journal A - Hadrons and Nuclei》2008,35(1):1-29
ISOLTRAP is a Penning trap mass spectrometer for high-precision mass measurements on short-lived nuclides installed at the
on-line isotope separator ISOLDE at CERN. The masses of close to 300 radionuclides have been determined up to now. The applicability
of Penning trap mass spectrometry to mass measurements of exotic nuclei has been extended considerably at ISOLTRAP by improving
and developing this double Penning trap mass spectrometer over the past two decades. The accurate determination of nuclear
binding energies far from stability includes nuclei that are produced at rates less than 100 ions/s and with half-lives well
below 100ms. The mass-resolving power reaches 107 corresponding to 10keV for medium heavy nuclei and the uncertainty of the resulting mass values has been pushed down to below
10-8. The article describes technical developments achieved since 1996 and the present performance of ISOLTRAP. 相似文献
73.
C. Scheidenberger 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):7-11
The present status and recent results from direct mass measurements of exotic nuclei are presented. ISOL, in-flight, and combined
facilities provide a wide variety of nuclides far-off stability covering a wide range of half-lives down to the sub-millisecond
region. Modern direct mass measurements are carried out using frequency and time-of-flight techniques. The obtained accurate
mass data point to nuclear-structure phenomena and serve as a basis for astrophysical and weak-interaction studies.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: c.scheidenberger@gsi.de 相似文献
74.
K. Blaum G. Bollen F. Herfurth A. Kellerbauer H.-J. Kluge M. Kuckein E. Sauvan C. Scheidenberger L. Schweikhard 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):245-248
The cyclotron frequencies of singly charged carbon clusters Cn
+ (n ≥ 2) were measured with the Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The present limit of mass accuracy δm/m = 1.2 . 10-8 and the extent of the mass-dependent systematic shift (δm/m)sys = 1.7(0.6) . 10-10/u
. (m - m
ref) of the setup were investigated for the first time. In addition, absolute mass measurements by use of pure clusters of the
most abundant carbon isotope 12C are now possible at ISOLTRAP.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"Present address: CERN, CH-1211 Geneva 23, Switzerland; e-mail: klaus.blaum@cern.ch 相似文献
75.
López-Suárez CE Castro-Romero JM González-Rodríguez MV González-Soto E Pérez-Iglesias J Seco-Lago HM Fernández-Solís JM 《Talanta》2000,50(6):325-1318
The ability of Chlorella vulgaris to accumulate heavy metals in solution (Mn, Cr, Ni, Zn and Cu) was investigated. Various parameters (algal biomass, pH and contact time of the algae with the sample) have been studied. Nine mg of algal biomass, pH 8 and 15 min of contact time, with 1 ppm of each metal, were the optimized conditions. At pH 8, the optimum value to rise the maximum binding, a fraction of metals in solution precipitates forming hydroxides. Combining both processes, a chemical–biological system for the removing of metals at ppb levels from the environment is obtained. The simultaneous determination of these five metals was performed by capillary electrophoresis (CE) with a UV/Vis detector. 相似文献
76.
S.??wiok W.?DudekEmail author P.?Kaszyński W.?Nazarewicz 《The European Physical Journal A - Hadrons and Nuclei》2005,23(3):387-393
The Greens function oscillator expansion method and the generalized Strutinsky smoothing procedure are applied to shell corrections in the heaviest elements. A macroscopic-microscopic method with a finite deformed Woods-Saxon potential is used. The stability condition for the shell correction is discussed in detail and the parameters defining the smoothing procedure are carefully determined. It is demonstrated that the spurious contribution to the total binding energy due to the unphysical particle gas that appears in the standard method can be as large as 1.5 MeV for weakly bound neutron-rich superheavy nuclei, but the effect on energy differences (e.g., alpha-decay values) is fairly small. 相似文献
77.
M.?-G.?PorquetEmail author S.?Péru M.?Girod 《The European Physical Journal A - Hadrons and Nuclei》2005,25(3):319-323
Self-consistent calculations using the D1S Gogny force have been performed in order to study the mechanism involved in the
crossing of the πd
5/2 and πg
7/2 orbitals in the Sb isotopes. This inversion is well predicted by the HFB + blocking calculations with spherical symmetry
performed for the odd-A Sb isotopes. In addition, several HFB and HF calculations have been performed for even-even nuclei of the five neighbouring
isotopic chains (Z = 46 to 54, from the proton dripline to N = 82). The results obtained for the binding energies of the two proton orbitals indicate that the radii of the systems play
an important role in the crossing, even though some particular πν interactions also give a contribution. The spin-orbit interaction,
which is known to be concentrated mainly at the nuclear surface, is proposed to be the main responsible of the crossing. 相似文献
78.
A. E. L. Dieperink P. Van Isacker 《The European Physical Journal A - Hadrons and Nuclei》2007,32(1):11-18
We discuss to what extent information on ground-state properties of finite nuclei (energies and radii) can be used to obtain
constraints on the symmetry energy in nuclear matter and its dependence on the density. The starting point is a generalized
Weizs?cker formula for ground-state energies. In particular, effects from the Wigner energy and shell structure on the symmetry
energy are investigated. Strong correlations in the parameter space prevent a clear isolation of the surface contribution.
Use of neutron skin information improves the situation. The result of the analysis appears consistent with a rather soft density
dependence of the symmetry energy in nuclear matter. 相似文献
79.
H. Hayashi Y. Akita O. Suematsu M. Shibata M. Asai T. K. Sato S. Ichikawa I. Nishinaka Y. Nagame A. Osa K. Tsukada T. Ishii Y. Kojima A. Taniguchi 《The European Physical Journal A - Hadrons and Nuclei》2007,34(4):363-370
Q
β values of the neutron-rich isotopes of 160-165Eu and 163Gd were measured for the first time using a total absorption bismuth germanate (BGO) detector, and previously obtained data
on 158, 159Pm , 159, 161Sm and 166Tb were re-analyzed. These radioactive sources were prepared by an on-line mass separator (Tokai-ISOL) following the 238U (p,f reaction. The deduced Q
β values are the following: 6085(80)keV for 158Pm , 3805(65)keV for 159Sm , 5460(140)keV for 159Pm , 4705(60)keV for 160Eu , 5065(130)keV for 161Sm , 3705(60)keV for 161Eu , 5575(60)keV for 162Eu , 4690(70)keV for 163Eu , 3170(70)keV for 163Gd , 6430(70)keV for 164Eu , 5800(120)keV for 165Eu , and 4695(70)keV for 166Tb . Moreover, the deduced mass excesses and two-neutron separation energies ( S
2n values) were compared with those of the atomic mass evaluations and theoretical predictions. 相似文献
80.
Modeling the effects of cohesive energy for single particle on the material removal in chemical mechanical polishing at atomic scale 总被引:1,自引:0,他引:1
This paper proposes a novel mathematical model for chemical mechanical polishing (CMP) based on interface solid physical and chemical theory in addition to energy equilibrium knowledge. And the effects of oxidation concentration and particle size on the material removal in CMP are investigated. It is shown that the mechanical energy and removal cohesive energy couple with the particle size, and being a cause of the non-linear size-removal rate relation. Furthermore, it also shows a nonlinear dependence of removal rate on removal cohesive energy. The model predictions are in good qualitative agreement with the published experimental data. The current study provides an important starting point for delineating the micro-removal mechanism in the CMP process at atomic scale. 相似文献