全文获取类型
收费全文 | 19114篇 |
免费 | 320篇 |
国内免费 | 319篇 |
专业分类
化学 | 10430篇 |
晶体学 | 139篇 |
力学 | 1444篇 |
综合类 | 17篇 |
数学 | 2714篇 |
物理学 | 5009篇 |
出版年
2020年 | 263篇 |
2019年 | 318篇 |
2018年 | 377篇 |
2017年 | 362篇 |
2016年 | 496篇 |
2015年 | 251篇 |
2014年 | 419篇 |
2013年 | 593篇 |
2012年 | 567篇 |
2011年 | 588篇 |
2010年 | 581篇 |
2009年 | 572篇 |
2008年 | 575篇 |
2007年 | 588篇 |
2006年 | 465篇 |
2005年 | 408篇 |
2004年 | 393篇 |
2003年 | 435篇 |
2002年 | 493篇 |
2001年 | 453篇 |
2000年 | 335篇 |
1999年 | 263篇 |
1998年 | 238篇 |
1997年 | 230篇 |
1993年 | 237篇 |
1992年 | 240篇 |
1991年 | 245篇 |
1990年 | 265篇 |
1989年 | 259篇 |
1987年 | 236篇 |
1986年 | 228篇 |
1985年 | 272篇 |
1984年 | 283篇 |
1983年 | 258篇 |
1982年 | 273篇 |
1981年 | 242篇 |
1980年 | 257篇 |
1979年 | 300篇 |
1978年 | 329篇 |
1977年 | 320篇 |
1976年 | 404篇 |
1975年 | 359篇 |
1974年 | 388篇 |
1973年 | 396篇 |
1972年 | 369篇 |
1971年 | 331篇 |
1970年 | 314篇 |
1969年 | 298篇 |
1968年 | 253篇 |
1967年 | 250篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
M. I. Kudryavtsev V. M. Pankov A. V. Bogomolov Yu. I. Denisov G. Ya. Kolesov Yu. I. Logachev S. I. Svertilov 《Radiophysics and Quantum Electronics》1996,39(11-12):1027-1030
The SPEKTR module of the MIR orbital station was launched in May 1995. The multipurpose experiment was based on the GRIF-1 research complex consisting of an oriented X-ray spectrometer, a spectrometer of gamma-quanta and neutrons, a spectrometer of electrons and protons with a large geometrical factor, and a spectrometer of electrons, protons, and nuclei with a small geometrical factor. The solar geophysical aspects of the experiment included the measurements of spectral and temporal parameters of solar hard electromagnetic (0.01–50 MeV) and neutron (>20 MзB) radiation, the study of spectral, temporal, and spatial characteristics of energetic electrons (0.04–1.5 MeV), protons, and nuclei (1–200 MeV/nucleon) in the circumterrestrial space, as well as the correlations of these parameters with solar activity phenomena. 相似文献
142.
A. V. Shapovalov I. V. Shirokov Ya. V. Lisitsyn V. I. Firstov 《Russian Physics Journal》1995,38(2):209-212
D'alambert's equation is used as an example to study the possibilities of a new method of exactly integrating systems of linear differential equations — the method of noncommutative integration (NI). The results confirm that use of the NI is equivalent to complete separation of the variables in the case of four-dimensional subalgebras of conformal algebra. However, the method does simplify determination of the exact solution in this instance.Tomsk University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 120–124, February, 1995. 相似文献
143.
Electron-positron production processes occurring in the interaction of 1018–1020 W/cm2 laser radiation with high-Z targets are examined. Computational results are presented for the pair production and the positron yield from the target
with allowance for the contribution of pair production processes due to electrons and bremsstrahlung photons. Monte Carlo
simulations using the PRIZMA code confirm the estimates obtained. The possible positron yield from high-Z targets irradiated with 102–103 TW laser radiation is estimated to be 109–1011.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 4, 239–244 (25 February 1998) 相似文献
144.
The problem of existence and approximate construction is studied for the solution of a nonlinear system of differential equations
with a transformed argument and linear multipoint boundary conditions.
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 50, No. 11, pp. 1581–1584, November, 1998. 相似文献
145.
The phase composition and the temperature dependence of the magnetization of the Er0.45Ho0.55Fe2 compound in coarse-grained, microcrystalline, and submicrocrystalline states are investigated experimentally. It is found
that, upon heating under vacuum, the Er0.45Ho0.55Fe2 microcrystalline powder with a crystalline grain size of ∼1 μm undergoes decomposition into pure iron and rare-earth (erbium
and holmium) oxides and nitrides at a temperature of 500 K. The changes observed in the phase composition of the microcrystalline
powder due to annealing are confirmed by x-ray diffraction analysis. Heating of the Er0.45Ho0.55Fe2 submicrocrystalline sample leads to a partial change in the phase composition. The phase composition of a large crystal (∼1
mm in size) remains unchanged upon heating to 1080 K. It is shown that the thermal stability of the Er0.45Ho0.55Fe2 compound depends on the crystalline grain size.
__________
Translated from Fizika Tverdogo Tela, Vol. 44, No. 6, 2002, pp. 1060–1063.
Original Russian Text Copyright ? 2002 by Mulyukov, Sharipov, Korznikova. 相似文献
146.
147.
We discuss general questions about the choice of optimization criteria for the stressed state of thermoelastic shells taking account of the functional measures of the space-time variability of its characteristics. The efficiency of the proposed approach is illustrated using the example of the solution of a problem for an axisymmetrically heated cylindrical shell.Translated fromMatematicheskie Metody i Fiziko-Mekhanicheskie Polya, Issue 27, 1988, pp. 11–18. 相似文献
148.
The behavior of the specific heat cp, effective mass M*, and the thermal expansion coefficient of a Fermi system located near the fermion condensation quantum phase transition (FCQPT) is considered. We observe the first type behavior if the system is close to FCQPT: the specific heat
,
, while the thermal expansion coefficient
. Thus, the Grüneisen ratio Γ(T)=/cp does not diverges. At the transition region, where the system passes over from the non-Fermi liquid to the Landau Fermi liquid, the ratio diverges as
. When the system becomes the Landau Fermi liquid, Γ(T,r)∝1/r, with r being a distance from the quantum critical point. Provided the system has undergone FCQPT, the second type takes place: the specific heat behaves as
, M*∝1/T, and =a+bT with a,b being constants. Again, the Grüneisen ratio diverges as
. 相似文献
149.
150.