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991.
We consider two possible zeta-function regularization schemes of quantum Liouville theory. One refers to the Laplace–Beltrami operator covariant under conformal transformations, the other to the naive noninvariant operator. The first produces an invariant regularization which however does not give rise to a theory invariant under the full conformal group. The other is equivalent to the regularization proposed by A.B. Zamolodchikov and Al.B. Zamolodchikov and gives rise to a theory invariant under the full conformal group. 相似文献
992.
也谈均匀带电细圆环的电场分布 总被引:1,自引:0,他引:1
用Mathematica研究均匀带电细圆环的电场的空间分布,准确地绘制出电场强度量值的分布图和电场方向的分布图,并纠正了最近文献中一幅场强量值分布图的失误. 相似文献
993.
994.
995.
T.Nakagawa M.Kidera Y.Higurasi J.Ohnishi T.Kageyama T.Aihara A.Goto Y.Yano 《中国物理 C》2007,31(Z1):133-136
We measured the main plasma parameters(density of electron,temperature of electron and ion confinement time)and beam intensity of various heavy ions as a function of B_(min).The B_(min) strongly affects the field gradient at the resonance zone,consequently the plasma parameters and beam intensity are changed. Based on these experimental results,we started to construct new 18GHz ECRIS and make a detailed design of the 28GHz SC-ECRIS for RIKEN RI beam factory project. 相似文献
996.
Arshak L. Vartanian Mkrtich A. Yeranosyan Albert A. Kirakosyan 《Physica B: Condensed Matter》2007,390(1-2):256-262
The hydrogenic impurity binding energy in rectangular quantum well wire including both barriers of finite height and an applied electric field are studied. The polaron effects on the ground-state binding energy in electric field are investigated by means of Landau-Pekar variation technique. The results for the binding energy as well as polaronic correction are obtained as a function of the size of the wire, the applied electric field and the position of the impurity. Our calculations are compared with previous results in quantum wires of comparable dimensions. 相似文献
997.
We characterize a method of heat-assisted magnetic probe recording on perpendicular media. Heating source is field emission current from a scanning tunneling microscope (STM) tip. Recording media are three kinds of magnetic films, Co/Pt, CoNi/Pt, and Co/Pd multilayers with different nucleation fields. Pulses with amplitude of 5 V were applied between the STM tip and the recording medium. Experiments show that magnetic marks with an average size of 180 nm were formed on both Co/Pt and CoNi/Pt films whose nucleation fields are greater than their saturation magnetization. No marks were observed on the Co/Pd film whose nucleation field is smaller than its saturation magnetization. A model is built to simulate the dynamic process of domain formation in probe-based magnetic recording system. Simulation results agree with experiments and it explains the effect of the nucleation field of medium in perpendicular recording. 相似文献
998.
Paul Halpern 《Physics in Perspective (PIP)》2007,9(4):390-405
I examine the changing attitudes of Oskar Klein (1894–1977) and Albert Einstein (1879–1955) toward the notion of extending
general relativity by an extra dimension with the aim of encompassing electromagnetism and gravitation in a unified field
theory. I show how Klein developed his model of five-dimensional unification with the goal of explaining the discreteness
of atomic energy levels, and how Einstein later embraced that goal. By examining the correspondence between Klein and Einstein,
some of which was relayed through Paul Ehrenfest (1880–1933), I speculate that Klein’s work helped motivate Einstein to explore
deterministic five-dimensional theories as a potential alternative to probabilistic quantum mechanics. Finally, I consider
the contributions of Wolfgang Pauli (1900–1958) to the subject and elucidate his role in convincing Klein and Einstein that
their models were not viable.
Paul Halpern is Professor of Physics at the University of the Sciences in Philadelphia. He currently is a member of the Executive
Committee of the Forum on the History of Physics of the American Physical Society. 相似文献
999.
Jean E. Burns 《Foundations of Physics》2007,37(12):1727-1737
Vacuum radiation causes a particle to make a random walk about its dynamical trajectory. In this random walk the root mean
square change in spatial coordinate is proportional to t
1/2, and the fractional changes in momentum and energy are proportional to t
−1/2, where t is time. Thus the exchange of energy and momentum between a particle and the vacuum tends to zero over time. At the end of
a mean free path the fractional change in momentum of a particle in a gas is very small. However, at the end of the mean free
path each particle undergoes an interaction that magnifies the preceding change, and the net result is that the momentum distribution
of the particles in a gas is randomized in a few collision times. In this way the random action of vacuum radiation and its
subsequent magnification by molecular interaction produces entropy increase. This process justifies the assumption of molecular
chaos used in the Boltzmann transport equation. 相似文献
1000.
Using resummation techniques based on the 2PI effective action we study the scalar φ
4 theory at finite temperature. We present an analytical as well as numerical study for a renormalized two-loop truncation
of the action. Both the spectral properties and critical behaviour of the theory are investigated. Within the truncation,
we explicitly check that the physical observables are UV-finite. 相似文献