全文获取类型
收费全文 | 175篇 |
免费 | 5篇 |
国内免费 | 18篇 |
专业分类
化学 | 72篇 |
力学 | 16篇 |
数学 | 2篇 |
物理学 | 108篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 5篇 |
2021年 | 7篇 |
2020年 | 2篇 |
2019年 | 8篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 4篇 |
2014年 | 11篇 |
2013年 | 10篇 |
2012年 | 3篇 |
2011年 | 23篇 |
2010年 | 15篇 |
2009年 | 16篇 |
2008年 | 17篇 |
2007年 | 6篇 |
2006年 | 10篇 |
2005年 | 6篇 |
2004年 | 9篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有198条查询结果,搜索用时 890 毫秒
131.
We study the properties of mixed quark–gluon condensate at finite temperature and chemical potential in the framework of global color symmetry model. In comparing with the quark condensate, we confirm that both of these condensates give the same information about chiral phase transition. We also find that the ratio of these two condensates is insensitive to the temperature T and the chemical potential μ, which supports the conclusion obtained recently by the authors using quenched lattice QCD. 相似文献
132.
M. Stoffel G. S. Kar U. Denker A. Rastelli H. Sigg O. G. Schmidt 《Physica E: Low-dimensional Systems and Nanostructures》2004,23(3-4):421
We investigate the embedding of Ge islands in a Si matrix by means of atomic force microscopy and photoluminescence (PL) spectroscopy. The Ge islands were grown between 360°C and 840°C and subsequently capped with Si at different temperatures. For the highest Ge growth temperature (840°C), we show that the surface flattens at high Si capping temperatures while new facets can be identified at the island base for intermediate capping temperatures (650–450°C). At low capping temperatures (300–350°C), the island morphology is preserved. In contrast to the observed island shape changes, the decreasing Si capping temperature causes only a small redshift of the island related PL signal for islands grown on high temperatures. This redshift increases for Ge islands grown at lower temperatures due to an increased Ge content in the islands. By applying low-temperature capping (300°C) on the different island types, we show that the emission wavelength can be extended up to 2.06 μm for hut clusters grown at 400°C. Further decreasing of the island growth temperature to 360°C leads to a PL blueshift, which is explained by charge carrier confinement in Ge quantum dots. 相似文献
133.
A chemically realistic model of 1,4-polybutadiene confined by graphite walls in a thin film geometry was studied by molecular dynamics simulations. The chemically realistic approach allows for a quantitative determination of a variety of experimentally accessible relaxation functions (e.g., dielectric, NMR, or neutron scattering responses). The simulations yield these experimental observables. Additionally, the simulations can be resolved as a function of distance to the solid interface on a much finer scale than experimentally possible, providing a detailed mechanistic picture of the segmental and large scale motions of polymers in the interfacial region between bulk polymer melts and solid walls. Extending the study of 1,4-polybutadiene on graphite to temperatures close to the glass transition temperature, we also address the question to what extent growing length scales associated with the glass transition influence the melt dynamics in the interphase. It was found that there is an interplay of this intrinsic slowing down with the adsorption/desorption kinetics of the chains close to the wall. It is argued that the monomer density changes near the wall can overcome the effect of rotational barriers only in a region of about 2 nm next to the wall. 相似文献
134.
We discuss the properties of ghost and gluon propagators in the deep infrared momentum region of Landau gauge Yang–Mills theory. Within the framework of Dyson–Schwinger equations and the functional renormalization group we demonstrate that it is only a matter of infrared boundary conditions whether infrared scaling or decoupling occurs. We argue that the second possibility is at odds with global BRST symmetry in the confining phase. For this purpose we improve upon existing truncation schemes in particular with respect to transversality and renormalization. 相似文献
135.
S. B. Rutkevich 《Journal of statistical physics》2008,131(5):917-939
We study the excitation energy spectrum in the S=1/2 ferromagnetic Ising spin chain with the easy axis z in a magnetic field h={h
x
,0,h
z
}. According to Wu and McCoy’s scenario of weak confinement, the fermionic spinon excitations (kinks), being free at h
z
=0 in the ordered phase, are coupled into bosonic bound states at arbitrary small h
z
>0. We calculate the energy spectrum of such excitations in the leading order in small h
z
, using different perturbative methods developed for the similar problem in the Ising Field Theory. 相似文献
136.
This paper details a methodology to test the mechanical response of soft, pressure sensitive materials, over a wide range of strain rates. A hybrid experimental-numerical procedure is used to assess the constitutive parameters. The experimental phase involves axial compression of a cylindrical specimen which is confined by a tightly-fit sleeve that is allowed to yield plastically, thus applying a constant confining pressure. The usually neglected frictional effects between the specimen and the sleeve are fully accounted for and characterized in detail. With commercial polycarbonate as a typical example, it is shown that pressure sensitivity and rate sensitivity are not coupled, thus reducing the number of tests needed to characterize a material. The results of numerical simulations indicate that the pressure sensitivity index (angle β in the Drucker-Prager material model) has little influence on the hydrostatic and confining pressures, whereas the equivalent stress sustained by the specimen increases with β, which for commercial polycarbonate is found to be β=15°. 相似文献
137.
Frédéric Jugeau 《Annals of Physics》2010,325(8):1739-1789
It is known, since the 70s, that the large N 't Hooft limit of gauge theories is related to string theories. In 1998, J. M. Maldacena identified precisely such a relation: the so-called AdS/CFT correspondence which speculates a duality between a large N strongly-coupled supersymmetric and conformal Yang-Mills theory in four dimensions and a weakly-coupled string theory defined in a five-dimensional anti-de Sitter AdS5 space-time. This review aims at introducing concepts and methods used to derive, in the framework of the gauge/string correspondence, the interaction potentials of mesons and baryons at zero and finite temperature. The dual string configurations associated with the different kinds of hadrons are described and their behaviours at short and large distances are understood. Although the application of Maldacena's AdS/CFT conjecture to QCD is not straightforward, QCD being neither supersymmetric nor conformal, the AdS/QCD correspondence approach attempts to identify the dual theory of QCD. Especially, the study of heavy quark-antiquark bound-states leads to establish general dual criteria for the confinement. 相似文献
138.
139.
Luiz C. L. Botelho 《International Journal of Theoretical Physics》2009,48(6):1701-1711
In this paper we intend to present some path-integral studies in the problem of confinement in the presence of fermionic and
scalar magnetic monopole fields through:
相似文献
1. | A Wilson Loop Path-Integral Evaluation associated to an effective second-quantized electromagnetic field generated by chiral abelian point-like monopole magnetic field current. |
2. | A Path-Integral Bosonization analysis of Quarks fields interacting with Kalb-Ramond fields considered as an effective Disorder Field Theory of a Q.C.D. vacuum of heavier monopoles. |
3. | Improvements on the Wilson Loops evaluations in the well-known ADHM Antonov-Ebert model for Cooper pairs of point-like fermionic magnetic monopoles. |
140.
Runaway reaction due to gas-dynamic choking in solid explosive containing a single crack 总被引:2,自引:0,他引:2
This work predicts the critical conditions required for the onset of reaction runaway in a narrow high-explosive slot intended to simulate a crack. A model is developed where slot pressurization is attributed to gas-dynamic choking at the slot exit. The combination of the choking and a pressure-dependent reaction rate is shown to be capable of predicting runaway reaction for a range of slot dimensions and pressures, even when the explosive regression is considered. This model agrees with experimental pressure measurements of reaction runaway in slots and provides a mechanism for the erratic burning observed with some explosives under high pressure. 相似文献