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991.
It is explicitly shown that if phase transition occurs at the core of a newborn neutron star with moderately strong magnetic
field strength, which populates only the electron’s Landau levels, then in the β -equilibrium condition, the quark core is
energetically much more unstable than the neutron matter of identical physical condition. 相似文献
992.
Mahendra K. Verma 《Pramana》2003,61(3):577-594
Energy cascade rates and Kolmogorov’s constant for non-helical steady magnetohydrodynamic turbulence have been calculated
by solving the flux equations to the first order in perturbation. For zero cross helicity and space dimensiond = 3, magnetic energy cascades from large length-scales to small length-scales (forward cascade). In addition, there are energy
fluxes from large-scale magnetic field to small-scale velocity field, large-scale velocity field to small-scale magnetic field,
and large-scale velocity field to large-scale magnetic field. Kolmogorov’s constant for magnetohydrodynamics is approximately
equal to that for fluid turbulence (≈ 1.6) for Alfvén ratio 05 ≤r
A ≤ ∞. For higher space-dimensions, the energy fluxes are qualitatively similar, and Kolmogorov’s constant varies asd
1/3. For the normalized cross helicity σc →1, the cascade rates are proportional to (1 − σc)/(1 + σc , and the Kolmogorov’s constants vary significantly with σcc. 相似文献
993.
Takayuki Sakaguchi 《Optical Review》2003,10(3):136-139
We have succeeded in the operation of rotating a fine particle which was held without mechanical contact by circularly polarized laser beams with opposite propagation directions. A polystyrene latex particle 11.9 μm in diameter deformed in a disk-like shape was dispersed in water, and was trapped using the anti-parallel collinear laser beams which were set up so that they had the circular polarization rotating in the same direction. It was observed that the trapped particle rotated in the same direction as the rotation of the circular polarization of light. Inversion of the rotational direction of the circular polarization of light reversed the direction of the rotation of the particle. Although the rotational speed of a particle varied significantly from particle to particle, it was found to be proportional to the laser beam intensity. A typical value for the rotational speed per beam intensity was 2.1 Hz/W. 相似文献
994.
Jean-Philippe Uzan 《General Relativity and Gravitation》2007,39(3):307-342
Using a general classification of dark enegy models in four classes, we discuss the complementarity of cosmological observations
to tackle down the physics beyond the acceleration of our universe. We discuss the tests distinguishing the four classes and
then focus on the dynamics of the perturbations in the Newtonian regime. We also exhibit explicitely models that have identical
predictions for a subset of observations. 相似文献
995.
Ebrahimi-Fard Kurusch José M. Gracia-Bondía Frédéric Patras 《Letters in Mathematical Physics》2007,81(1):61-75
The word problem for an arbitrary associative Rota–Baxter algebra is solved. This leads to a noncommutative generalization
of the classical Spitzer identities. Links to other combinatorial aspects are indicated.
相似文献
996.
Measuring particle size-dependent physicochemical structure in airborne
single walled carbon nanotube agglomerates 总被引:1,自引:1,他引:1
Andrew D. Maynard Bon Ki Ku Mark Emery Mark Stolzenburg Peter H. McMurry 《Journal of nanoparticle research》2007,9(1):85-92
As-produced single-walled carbon nanotube (SWCNT) material is a complex matrix of carbon nanotubes, bundles of nanotubes (nanoropes),
non-tubular carbon and metal catalyst nanoparticles. The pulmonary toxicity of material released during manufacture and handling
will depend on the partitioning and arrangement of these components within airborne particles. To probe the physicochemical
structure of airborne SWCNT aggregates, a new technique was developed and applied to aerosolized as-produced material. Differential
Mobility Analysis-classified aggregates were analyzed using an Aerosol Particle Mass Monitor, and a structural parameter Γ
(proportional to the square of particle mobility diameter, divided by APM voltage) derived. Using information on the constituent
components of the SWCNT, modal values of Γ were estimated for specific particle compositions and structures, and compared
against measured values. Measured modal values of Γ for 150 nm mobility diameter aggregates suggested they were primarily
composed of non-tubular carbon from one batch of material, and thin nanoropes from a second batch of material – these findings
were confirmed using Transmission Electron Microscopy. Measured modal values of Γ for 31 nm mobility diameter aggregates indicated
that they were comprised predominantly of thin carbon nanoropes with associated nanometer-diameter metal catalyst particles;
there was no indication that either catalyst particles or non-tubular carbon particles were being preferentially released
into the air. These results indicate that the physicochemistry of aerosol particles released while handling as-produced SWCNT
may vary significantly by particle size and production batch, and that evaluations of potential health hazards need to account
for this.
Disclaimer: The mention of any company or product does not constitute an endorsement by the Centers for Disease Control and
Prevention. The findings and conclusions in this paper are those of the authors and do not necessarily represent the views
of the National Institute for Occupational Safety and Health. 相似文献
997.
Qing-Quan Jiang Wei Ren Jian Tang Xiao-Feng Liu 《International Journal of Theoretical Physics》2007,46(6):1449-1454
Applying the semi-classical quantum tunneling model, we have studied the Hawking radiation via tunneling from a cylindrically
symmetric black hole. The derived results show that the tunneling rate of at the event horizon of the black hole is related
to Bekenstein–Hawking entropy and the factual radiation spectrum is not strictly pure thermal, but is consistent with the
underlying unitary theory.
PACS numbers: 04.20.-s, 97.60.Lf. 相似文献
998.
We show that the exact energy eigenvalues and eigenfunctions of the Schrödinger equation for charged particles moving in certain class of non-central potentials can be easily calculated analytically in a simple and elegant manner by using Nikiforov and Uvarov (NU) method. We discuss the generalized Coulomb and harmonic oscillator systems. We study the Hartmann Coulomb and the ring-shaped and compound Coulomb plus Aharanov–Bohm potentials as special cases. The results are in exact agreement with other methods. 相似文献
999.
Daniel S. Freed Gregory W. Moore Graeme Segal 《Communications in Mathematical Physics》2007,271(1):247-274
In the ordinary quantum Maxwell theory of a free electromagnetic field, formulated on a curved 3-manifold, we observe that
magnetic and electric fluxes cannot be simultaneously measured. This uncertainty principle reflects torsion: fluxes modulo
torsion can be simultaneously measured. We also develop the Hamilton theory of self-dual fields, noting that they are quantized
by Pontrjagin self-dual cohomology theories and that the quantum Hilbert space is -graded, so typically contains both bosonic and fermionic states. Significantly, these ideas apply to the Ramond-Ramond field
in string theory, showing that its K-theory class cannot be measured. 相似文献
1000.
Zhongzhi Zhang Shuigeng Zhou Tao Zou Lichao Chen Jihong Guan 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,60(2):259-264
We make a mapping from Sierpinski fractals to a new class
of networks, the incompatibility networks, which are scale-free,
small-world, disassortative, and maximal planar graphs. Some
relevant characteristics of the networks such as degree
distribution, clustering coefficient, average path length, and
degree correlations are computed analytically and found to be
peculiarly rich. The method of network representation can be applied
to some real-life systems making it possible to study the complexity
of real networked systems within the framework of complex network
theory. 相似文献