全文获取类型
收费全文 | 909篇 |
免费 | 143篇 |
国内免费 | 57篇 |
专业分类
化学 | 429篇 |
晶体学 | 23篇 |
力学 | 27篇 |
综合类 | 3篇 |
数学 | 17篇 |
物理学 | 610篇 |
出版年
2023年 | 11篇 |
2022年 | 20篇 |
2021年 | 23篇 |
2020年 | 23篇 |
2019年 | 15篇 |
2018年 | 19篇 |
2017年 | 23篇 |
2016年 | 38篇 |
2015年 | 26篇 |
2014年 | 23篇 |
2013年 | 105篇 |
2012年 | 39篇 |
2011年 | 37篇 |
2010年 | 50篇 |
2009年 | 52篇 |
2008年 | 29篇 |
2007年 | 36篇 |
2006年 | 38篇 |
2005年 | 21篇 |
2004年 | 25篇 |
2003年 | 27篇 |
2002年 | 95篇 |
2001年 | 32篇 |
2000年 | 26篇 |
1999年 | 20篇 |
1998年 | 43篇 |
1997年 | 28篇 |
1996年 | 22篇 |
1995年 | 23篇 |
1994年 | 36篇 |
1993年 | 28篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1988年 | 17篇 |
1987年 | 9篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有1109条查询结果,搜索用时 15 毫秒
61.
S. Tomita M. Kato K. Maki 《Physica C: Superconductivity and its Applications》2009,469(15-20):1074-1076
For analyzing the checker-board like modulation of the local density of states (LDOS) around a vortex observed in the slightly overdoped Bi2Sr2CaCu2Ox, we examined the effect of pseudogap state of high-Tc superconductors to the LDOS around the vortex. We first derived the Bogoliubov-de Gennes equation for d-wave superconductivity (d-SC) in the presence of d-spin density wave (d-SDW). Using the Fourier–Bessel expansion, we solved this equation for a single vortex state, numerically. We found that the peak of the bound states around E = 0 becomes small and modulation of the LDOS is observed for larger d-SDW order parameter. 相似文献
62.
We present an on-line library of unprecedented extension for high-temperature expansions of basic observables in the Ising models of general spin S, with nearest-neighbor interactions. We have tabulated through order
25 the series for the nearest-neighbor correlation function, the susceptibility and the second correlation moment in two dimensions on the square lattice, and, in three dimensions, on the simple-cubic and the body-centered cubic lattices. The expansion of the second field derivative of the susceptibility is also tabulated through
23 for the same lattices. We have thus added several terms (from four up to thirteen) to the series already published for spin S = 1/2, 1, 3/2, 2, 5/2, 3, 7/2, 4, 5, . 相似文献
63.
M. R. Koblischka S. L. Huang K. Fossheim T. H. Johansen H. Bratsberg 《Physica C: Superconductivity and its Applications》1998,300(3-4):207-211
Flux distributions of partial-melting processed Bi2Sr2CaCu2O8+δ ceramics are obtained using magneto-optic imaging. In remanent states (μ0Ha=0 T), large amounts of trapped flux are observed along (Sr,Ca)2CuOy particles embedded in the Bi2Sr2CaCu2O8+δ matrix. Despite the relatively large size of these particles (up to 30 μm), the pinning effect is similar to that of Y2BaCuO5 particles in melt-processed YBa2Cu3O7−δ. Furthermore, we discuss how the pinning capability of non-superconducting particles of different sizes and densities will show up in magneto-optic images. 相似文献
64.
T. Mimura I. Terasaki K. Tomimoto S. Tajima M. Nakamura Y. Shiohara 《Physica C: Superconductivity and its Applications》1998,300(3-4):212-216
In order to clarify the origin of a strong peak effect in the magnetization curve of NdBa2Cu3O7−δ crystals, we investigated the superconductivity transition behavior of the in-plane resistivity in static magnetic fields up to 8 T. Comparing the results for the samples exhibiting and not exhibiting the peak effect, we found that the former (peak effect sample) shows lower resistivity above the vortex melting temperature. This implies that the pinning force is effective in the vortex liquid state. We also found that the normal state resistivity behaviors of some samples were unusual, indicating inhomogeneous current flow. These results suggest an existence of sheet-like pinning centers perpendicular to the conduction planes. 相似文献
65.
R. R. Mahajan P. S. Makashir J. P. Agrawal 《Journal of Thermal Analysis and Calorimetry》2001,65(3):935-942
Complexes of nitrocellulose (NC – low and high nitrogen content) with copper oxide (CuO) have been synthesized and studied
for morphological behaviour on heating from room temperature to 500°C with the help of hot stage microscopy (HSM).
During decomposition, NC:CuO complexes show contraction of fibrous boundaries followed by mass movement of matrix, with the
evolution of brown yellow colour gas at higher temperatures as compared to NC alone.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
66.
W. P. Orrick B. Nickel A. J. Guttmann J. H. H. Perk 《Journal of statistical physics》2001,102(3-4):795-841
We have made substantial advances in elucidating the properties of the susceptibility of the square lattice Ising model. We discuss its analyticity properties, certain closed form expressions for subsets of the coefficients, and give an algorithm of complexity O(N6) to determine its first N coefficients. As a result, we have generated and analyzed series with more than 300 terms in both the high- and low-temperature regime. We quantify the effect of irrelevant variables to the scaling-amplitude functions. In particular, we find and quantify the breakdown of simple scaling, in the absence of irrelevant scaling fields, arising first at order |T–Tc|9/4, though high-low temperature symmetry is still preserved. At terms of order |T–Tc|17/4 and beyond, this symmetry is no longer present. The short-distance terms are shown to have the form (T–Tc)p (log |T–Tc|)q with pq2. Conjectured exact expressions for some correlation functions and series coefficients in terms of elliptic theta functions also foreshadow future developments. 相似文献
67.
R. Menegotto Costa L. Mendon?a Ferreira V. N. Vieira P. Pureur J. Schaf 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,58(2):107-113
We have studied experimentally the electrical magneto-conductivity near the
superconducting transition of YBa2Cu3O7-δ, YBa2
(Cu2.95Zn0.05)O7-δ and Y(Ba1.75Sr0.25)Cu3O7-δ polycrystalline samples. The measurements were performed in magnetic fields ranging from 0 to 400 Oe applied parallel to
the current orientation. The results show that the resistive transition of these systems proceeds in two stages. The pairing
transition occurs at the bulk critical temperature Tc, where superconductivity is stabilized within small and homogeneous regions of the
sample generically called grains. The regime of approach to the zero resistance state reveals the occurrence of a coherence
transition at a lower temperature Tc0. This transition is related to the connective nature of the granular samples and is controlled by fluctuations of the
order-parameter phase of individual grains. Our experiments show that the Zn-doping, besides depressing the pairing critical
temperature, strongly enlarges the temperature range dominated by effects related to the coherence transition. The substitution
of Ba by Sr causes only a small reduction of Tc, but also enhances significantly the effects related to the grain
coupling phenomenology. In general, our results indicate that these impurity substitutions in YBa2Cu3O7-δ produce or magnify the granularity at a microscopic level, enhancing the effects of phase fluctuations in the conductivity
near the transition. 相似文献
68.
M. M. Korshunov S. G. Ovchinnikov 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,57(3):271-278
In this paper a mean-field theory for the spin-liquid paramagnetic non-superconducting phase of the p- and n-type high-Tc cuprates is developed. This theory applied to the effective t-t'-t′′-J* model with the ab initio calculated parameters and with the three-site correlated hoppings. The static spin-spin and kinematic
correlation functions beyond Hubbard-I approximation are calculated self-consistently. The evolution of the Fermi surface
and band dispersion is obtained for the wide range of doping concentrations x. For p-type systems the three different types
of behavior are found and the transitions between these types are accompanied by the changes in the Fermi surface topology.
Thus a quantum phase transitions take place at x = 0.15 and at x = 0.23.Due to the different Fermi surface topology we found
for n-type cuprates only one quantum critical concentration, x = 0.2. The calculated doping dependence of the nodal Fermi
velocity and the effective mass are in good agreement with the experimental data. 相似文献
69.
U. Schwingenschlögl C. Schuster 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,55(1):43-47
The incommensurate composite systems M14Cu24O41 (M = Ca, Sr, La)
are based on two fundamental structural units: CuO2 chains and
Cu2O3 ladders. We present electronic structure calculations
within density functional theory in order to address the interrelations
between chains and ladders. The calculations account for the
details of the crystal structure by means of a unit cell comprising 10
chain and 7 ladder units. It turns out that chains and ladders can be treated
independently, which allows us to introduce a model system based on a
reduced unit cell. For the CuO2 chains, we find two characteristic
bands at the Fermi energy. Tight binding fits yield
nearest and next-nearest neighbour interactions of the same order of
magnitude. 相似文献
70.