全文获取类型
收费全文 | 14197篇 |
免费 | 2419篇 |
国内免费 | 1859篇 |
专业分类
化学 | 5354篇 |
晶体学 | 379篇 |
力学 | 899篇 |
综合类 | 137篇 |
数学 | 181篇 |
物理学 | 5554篇 |
无线电 | 5971篇 |
出版年
2024年 | 36篇 |
2023年 | 144篇 |
2022年 | 287篇 |
2021年 | 421篇 |
2020年 | 398篇 |
2019年 | 368篇 |
2018年 | 385篇 |
2017年 | 544篇 |
2016年 | 639篇 |
2015年 | 630篇 |
2014年 | 846篇 |
2013年 | 1143篇 |
2012年 | 1102篇 |
2011年 | 1048篇 |
2010年 | 853篇 |
2009年 | 920篇 |
2008年 | 946篇 |
2007年 | 972篇 |
2006年 | 834篇 |
2005年 | 759篇 |
2004年 | 703篇 |
2003年 | 587篇 |
2002年 | 479篇 |
2001年 | 428篇 |
2000年 | 411篇 |
1999年 | 376篇 |
1998年 | 309篇 |
1997年 | 282篇 |
1996年 | 249篇 |
1995年 | 210篇 |
1994年 | 184篇 |
1993年 | 186篇 |
1992年 | 154篇 |
1991年 | 90篇 |
1990年 | 92篇 |
1989年 | 79篇 |
1988年 | 87篇 |
1987年 | 48篇 |
1986年 | 41篇 |
1985年 | 24篇 |
1984年 | 19篇 |
1983年 | 13篇 |
1982年 | 30篇 |
1981年 | 25篇 |
1980年 | 15篇 |
1979年 | 25篇 |
1978年 | 15篇 |
1977年 | 12篇 |
1976年 | 7篇 |
1974年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 453 毫秒
151.
152.
Applying a Lindemann like criterion obtained previously by Kierfeld et al. [J. Kierfeld, T. Nattermann, T. Hwa, Phys. Rev. B 55 (1997) 626], we estimate the magnetic field and temperature for a high-Tc superconductor, at which a topologically ordered vortex glass phase becomes unstable with respect to a disorder-induced formation of dislocations. The employed criterion is shown to be equivalent to a conventional phenomenological Lindemann criterion including the values for the numerical factors, i.e., for the Lindemann number. The positional correlation length of the topologically ordered vortex glass is calculated. 相似文献
153.
154.
Summary Equilibrium equations and stability conditions for the simple deformable elastic body are derived by means of considering
a minimum of the static energy principle. The energy is supposed to be sum of the volume (elastic) and the surface terms.
The ability to change relative positions of different material particles is taken into account, and appropriate natural definitions
of the first and second variations of the energy are introduced and calculated explicitly. Considering the case of negligible
magnitude of the surface tension, we establish that an equilibrium state of a nonhydrostatically stressed simple elastic body
(of any physically reasonable elastic energy potential and of any symmetry) possessing any small smooth part of free surface
is always unstable with respect to relative transfer of the material particles along the surface. Surface tension suppresses
the mentioned instability with respect to sufficiently short disturbances of the boundary surface and thus can probably provide
local smoothness of the equilibrium shape of the crystal. We derive explicit formulas for critical wavelength for the simplest
models of the internal and surface energies and for the simplest equilibrium configurations. We also formulate the simplest
problem of mathematical physics, revealing peculiarities and difficulties of the problem of equilibrium shape of elastic crystals,
and discuss possible manifestations of the above-mentioned instability in the problems of crystal growth, materials science,
fracture, physical chemistry, and low-temperature physics. 相似文献
155.
156.
离子注入硅的线源非相干光瞬时退火温度计算 总被引:1,自引:0,他引:1
本文利用高温模型,计算了在我们的实验条件下对离子注入硅进行线源非相干光瞬时退火的退火温度,并与实验结果比较,两者符合得较好。 相似文献
157.
158.
Domingos H. U. Marchetti 《Journal of statistical physics》1990,61(3-4):909-911
A simple argument is presented by which one can show that the critical inverse temperature
c
of a two-dimensional Coulomb gas (standard or hard-core) with activityz satisfies
, where
in the low-activity limit. Previous results yield
. 相似文献
159.
Tom Kennedy 《Journal of statistical physics》1990,59(1-2):195-220
A fixed-point equation on an infinite-dimensional space is proposed as an alternative to the usual definition of the infinite-volume limit in discrete lattice spin systems in the high-temperature phase. It is argued heuristically that the free energy and correlation functions one obtains by solving this equation agree with the usual definitions of these quantities. A theorem is then proved that says that if a certain finite-volume condition is satisfied, then this fixed-point equation has a solution and the resulting free energy is analytic in the parameters in the Hamiltonian. For particular values of the temperature this finite-volume condition may be checked with the help of a computer. The two-dimensional Ising model is considered as a test case, and it is shown that the finite-volume condition is satisfied for0.77
critical. 相似文献
160.
Yuichiro Tada Masakatsu Ueno Noriaki Tsuchihashi Kiyoshi Shimizu 《Journal of solution chemistry》1992,21(9):971-985
The limiting molar conductances ° of deuterium chloride DCl in D2O were determined as a function of pressure and temperature in order to examine the proton-jump mechanism in detail. The excess deuteron conductances °E(D
+), as estimated by the equation [°E(D
+) = °(DCl/D
2
O) – °(KCl/D
2
O)], increases with an increase in the pressure and temperature as well as the excess proton conductance [°E(H
+) = °(HCl/H
2
O) – °(KCl/H
2
O)]. The isotope effect on the excess conductances, however, depends on the pressure and temperature contrary to the model proposed by Conway et al.: °E(H
+)/°E(D
+) decreases with increasing pressure and temperature. The magnitude of the decrease with pressure becomes more prominent at lower temperature. These results are discussed in terms of the pre-rotation of adjacent water molecules, the bending of hydrogen bonds with pressure, and the difference in strength of hydrogen bonds between D2O and H2O. 相似文献