全文获取类型
收费全文 | 140400篇 |
免费 | 11132篇 |
国内免费 | 8128篇 |
专业分类
化学 | 69089篇 |
晶体学 | 1659篇 |
力学 | 10216篇 |
综合类 | 480篇 |
数学 | 38512篇 |
物理学 | 39704篇 |
出版年
2024年 | 227篇 |
2023年 | 1376篇 |
2022年 | 2576篇 |
2021年 | 2783篇 |
2020年 | 2877篇 |
2019年 | 2756篇 |
2018年 | 12272篇 |
2017年 | 12076篇 |
2016年 | 9040篇 |
2015年 | 4182篇 |
2014年 | 4302篇 |
2013年 | 5410篇 |
2012年 | 9749篇 |
2011年 | 16156篇 |
2010年 | 9679篇 |
2009年 | 9788篇 |
2008年 | 10682篇 |
2007年 | 12218篇 |
2006年 | 3522篇 |
2005年 | 4047篇 |
2004年 | 3635篇 |
2003年 | 3608篇 |
2002年 | 2511篇 |
2001年 | 1461篇 |
2000年 | 1363篇 |
1999年 | 1362篇 |
1998年 | 1159篇 |
1997年 | 1030篇 |
1996年 | 1092篇 |
1995年 | 903篇 |
1994年 | 754篇 |
1993年 | 668篇 |
1992年 | 532篇 |
1991年 | 503篇 |
1990年 | 407篇 |
1989年 | 327篇 |
1988年 | 253篇 |
1987年 | 233篇 |
1986年 | 242篇 |
1985年 | 202篇 |
1984年 | 133篇 |
1983年 | 133篇 |
1982年 | 100篇 |
1981年 | 79篇 |
1980年 | 75篇 |
1979年 | 63篇 |
1978年 | 43篇 |
1973年 | 41篇 |
1914年 | 45篇 |
1909年 | 41篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
132.
We prove that any 43-fold covering of the plane with translates of a triangle can be decomposed into two coverings. 相似文献
133.
134.
Roderich Tumulka 《Foundations of Physics》2007,37(2):186-197
In a recent paper Conway and Kochen, Found. Phys. 36, 2006, claim to have established that theories of the Ghirardi-Rimini-Weber
(RW) type, i.e., of spontaneous wave function collapse, cannot be made relativistic. On the other hand, relativistic GRW-type
theories have already been presented, in my recent paper, J. Stat. Phys. 125, 2006, and by Dowker and Henson, J. Stat. Phys.
115, 2004. Here, I elucidate why these are not excluded by the arguments of Conway and Kochen.
相似文献
135.
The Bekenstein–Hawking entropy of certain black holes can be computed microscopically in string theory by mapping the elusive
problem of counting microstates of a strongly gravitating black hole to the tractable problem of counting microstates of a
weakly coupled D-brane system, which has no event horizon, and indeed comfortably fits on the head of a pin. We show here
that, contrary to widely held beliefs, the entropy of spherically symmetric black holes can easily be dwarfed by that of stationary
multi-black-hole “molecules” of the same total charge and energy. Thus, the corresponding pin-sized D-brane systems do not
even approximately count the microstates of a single black hole, but rather those of a zoo of entropically dominant multicentered
configurations.
Fourth Award in the 2007 Essay Competition of the Gravity Research Foundation. 相似文献
136.
M. Vedani G. Angella Paola Bassani D. Ripamonti A. Tuissi 《Journal of Thermal Analysis and Calorimetry》2007,87(1):277-284
Equal channel angular
pressing (ECAP) was carried out on solution annealed samples of Al–Mg–Si–Zr
and Al–Mg–Si–Zr–Sc alloys to achieve a substantial
grain refinement of the materials. Post ECAP aging was then investigated on
the ultrafine grained alloys by DSC and TEM analyses.
DSC scans
were carried out with heating rates ranging from 5 to 30°C min–1.
Peak identification was performed by the support of literature information
and TEM analyses. Precipitation kinetics revealed to be similar for both alloys
but the Sc-free alloy showed a recrystallization peak at temperatures ranging
from 310 to 340°C, depending on the strain accumulated during ECAP. On
the contrary, the Sc-containing alloy showed a greater grain stability. Analyses
of peak positions and of activation energies as a function of ECAP passes
experienced by the samples revealed large modifications of precipitation kinetics
in the ultrafine-grained alloys with respect to the coarse-grained materials. 相似文献
137.
Maxim V. Pavlov 《Communications in Mathematical Physics》2007,272(2):469-505
The algebro-geometric approach for integrability of semi-Hamiltonian hydrodynamic type systems is presented. The class of
symmetric hydrodynamic type systems is defined and the calculation of the associated Riemann surfaces is greatly simplified for this
class. Many interesting and physically motivated examples are investigated. 相似文献
138.
Chii-Wann Lin Kuo-Ping Chen Ming-Chii Su Chih-Kung Lee Chih-Chung Yang 《Optical and Quantum Electronics》2005,37(13-15):1423-1437
We have reported a novel design of surface plasmon resonance (SPR) device, which uses alternating dielectric layers to enhance the SPR signal quality and modulate its resonant position. Admittance loci method of thin film design has been used in the design of such a device. The use of biomolecular thin film, such as DNAs or Porteins, in this design can result in resonant condition of wavelength changes as well. Bio-plasmonics is proposed for the research and development of novel devices, which use biomolecules as a part of the plasmon oscillation system to actively interact with nano/micro structure. 相似文献
139.
Yang Zuosheng 《国际流体数值方法杂志》2005,47(12):1423-1430
A complete boundary integral formulation for compressible Navier–Stokes equations with time discretization by operator splitting is developed using the fundamental solutions of the Helmholtz operator equation with different order. The numerical results for wall pressure and wall skin friction of two‐dimensional compressible laminar viscous flow around airfoils are in good agreement with field numerical methods. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
140.
Kwang-Hua W. Chu 《International Journal of Theoretical Physics》2007,46(12):3230-3233
The modified Gross–Pitaevskii equation was derived and solved to obtain the 1D solution in the zero-energy limit. This stationary
solution could account for the dominated contributions due to the kinetic effect as well as the chemical potential in inhomogeneous
Bose gases. 相似文献