全文获取类型
收费全文 | 122808篇 |
免费 | 6855篇 |
国内免费 | 7620篇 |
专业分类
化学 | 73670篇 |
晶体学 | 1454篇 |
力学 | 6417篇 |
综合类 | 383篇 |
数学 | 15484篇 |
物理学 | 39875篇 |
出版年
2023年 | 832篇 |
2022年 | 1464篇 |
2021年 | 2380篇 |
2020年 | 2606篇 |
2019年 | 2827篇 |
2018年 | 3149篇 |
2017年 | 3068篇 |
2016年 | 4103篇 |
2015年 | 2916篇 |
2014年 | 4081篇 |
2013年 | 6262篇 |
2012年 | 6492篇 |
2011年 | 8056篇 |
2010年 | 5735篇 |
2009年 | 5797篇 |
2008年 | 5668篇 |
2007年 | 5361篇 |
2006年 | 4880篇 |
2005年 | 4701篇 |
2004年 | 5342篇 |
2003年 | 4237篇 |
2002年 | 4147篇 |
2001年 | 3406篇 |
2000年 | 2500篇 |
1999年 | 2046篇 |
1998年 | 1977篇 |
1997年 | 1690篇 |
1996年 | 1603篇 |
1995年 | 1362篇 |
1994年 | 1369篇 |
1993年 | 1647篇 |
1992年 | 1634篇 |
1991年 | 1480篇 |
1990年 | 1484篇 |
1989年 | 1395篇 |
1988年 | 1052篇 |
1987年 | 985篇 |
1986年 | 976篇 |
1985年 | 1032篇 |
1984年 | 1028篇 |
1983年 | 904篇 |
1982年 | 870篇 |
1979年 | 838篇 |
1978年 | 845篇 |
1977年 | 844篇 |
1976年 | 945篇 |
1975年 | 837篇 |
1974年 | 870篇 |
1973年 | 860篇 |
1972年 | 769篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
A. N. Vasiliev V. N. Grishin A. M. Davidenko A. A. Derevschikov Yu. A. Matulenko Yu. M. Melnik A. P. Meschanin V. V. Mochalov L. V. Nogach S. B. Nurushev A. F. Prudkoglyad P. A. Semenov L. F. Soloviev V. L. Solovianov V. Yu. Khodyrev K. E. Shestermanov A. E. Yakutin N. S. Borisov V. N. Matafonov A. B. Neganov Yu. A. Plis Yu. A. Usov A. N. Fedorov A. A. Lukhanin 《Physics of Atomic Nuclei》2004,67(8):1487-1494
Results are presented that were obtained by measuring single-spin asymmetry in the inclusive production of neutral pions in the reaction p+p ↑→ π 0+X at x F≈0. A beam of 70-GeV protons was extracted directly from the vacuum chamber of the accelerator by means of a bent single crystal. For transverse momenta in the range 1.0<p T<3.0 GeV/c, the single-spin asymmetry independently measured by two detectors is zero within the errors. This result is in agreement with Fermilab data obtained at 200 GeV, but it is at odds with CERN data measured at 24 GeV. 相似文献
992.
The results obtained upon the electrochemical deposition of composite coatings containing ultrafine-dispersed diamonds produced by detonation synthesis are generalized. The main advantages of such coatings over the well-known composite electrochemical coatings are revealed. 相似文献
993.
P. K. Kashkarov B. V. Kamenev M. G. Lisachenko O. A. Shalygina V. Yu. Timoshenk M. Schmidt J. Heitmann M. Zacharias 《Physics of the Solid State》2004,46(1):104-108
The photoluminescence spectra and kinetics of both erbium-doped and undoped multilayer structures of quasi-ordered silicon
nanocrystals in a silicon dioxide matrix were studied. It was shown that the optical excitation energy of silicon nanocrystals
2–3 nm in size can be practically completely transferred to Er3+ ions in the oxide surrounding the nanocrystals, with its subsequent radiation at 1.5 μm. Possible reasons for the high excitation
efficiency of the Er3+ ions are discussed, and the conclusion is drawn that the F?rster mechanism is dominant in the energy transfer processes occurring
in these structures.
__________
Translated from Fizika Tverdogo Tela, Vol. 46, No. 1, 2004, pp. 105–109.
Original Russian Text Copyright ? 2004 by Kashkarov, Kamenev, Lisachenko, Shalygina, Timoshenko, Schmidt, Heitmann, Zacharias. 相似文献
994.
A. N. Enyashin V. V. Ivanovskaya Yu. N. Makurin A. L. Ivanovskii 《Physics of the Solid State》2004,46(8):1569-1573
A comparative analysis of the stability factors and electronic structure of two possible crystalline forms of small fullerene C28 and endohedral fullerene Zn@C28 with diamond and lonsdaleite structures is performed using a cluster model. Atoms of elements that, when placed inside C28 cages, have no significant effect on the stability of free small-fullerene molecules are shown to be able to dramatically change the electronic properties and reactivity of the C28 skeleton and to be favorable for forming small-fullerene crystalline modifications, which are covalent crystals. In contrast, if the presence of foreign atoms inside C28 cages stabilizes the isolated nanoparticles, then molecular crystals (such as C60 fullerites) are formed due to weak van der Waals forces. 相似文献
995.
By means of the multichannel Hartree-Fock-Dirac method, the parameters β and α2 of the angular distribution of Auger electrons and the parameter β2 of their spin polarization are calculated for sodium, krypton, xenon, barium, mercury, and excited argon. Relevant Coulomb
matrix elements are determined by using orthogonal multielectron initial-and final-state wave functions for intermediate-type
coupling in a relativistic approximation. Exchange interaction is taken into account in all calculations. A comparison of
the results of calculations performed in the frozen-core approximation and those obtained with orthogonal initial-and final-state
wave functions reveals that the relaxation of core orbital processes has only a slight effect on the anisotropy parameters
of the angular distribution. The resulting values of the parameters β, α2, and β2 are compared with the results of different calculations. 相似文献
996.
In the present paper, the probability of creating pairs of scalar particles in an arbitrary plane electromagnetic wave field is calculated. The amplitude of elastic photon scattering in the field of an arbitrary plane electromagnetic wave is calculated by the method of dispersion relations. Special cases of the plane electromagnetic wave field are examined. 相似文献
997.
998.
Classification of three-dimensional periodic fluid flows 总被引:1,自引:0,他引:1
999.
G. M. Ter-Akopian A. V. Daniel A. S. Fomichev G. S. Popeko A. M. Rodin Yu. Ts. Oganessian J. H. Hamilton A. V. Ramayya J. Kormicki J. K. Hwang D. Fong P. Gore J. D. Cole M. Jandel J. Kliman L. Krupa J. O. Rasmussen I. Y. Lee A. O. Macchiavelli P. Fallon M. A. Stoyer R. Donangelo S. -C. Wu W. Greiner 《Physics of Atomic Nuclei》2004,67(10):1860-1865
Ternary fission of 252Cf was studied at Gammasphere using eight ΔE×E particle telescopes. Helium, beryllium, boron, and carbon light charged particles (LCPs) emitted with kinetic energy more than 9, 21, 26, and 32 MeV, respectively, were identified. The 3368-keV γ transition from the first 2+ excited state in 10Be was found and the population probability ratio N(2+)/N(0+) = 0.160 ± 0.025 was estimated. No evidence was found for 3368-keV γ rays emitted from a triple molecular state. For the first time, charge distributions are obtained for ternary fission fragments emitted with helium, beryllium, and carbon LCPs. 相似文献
1000.
G. E. Abrosimova A. S. Aronin Yu. P. Kabanov D. V. Matveev V. V. Molokanov 《Physics of the Solid State》2004,46(5):885-890
The structure forming under controlled crystallization of a bulk Fe72Al5P10Ga2C6B4Si1 amorphous alloy has been studied using differential scanning calorimetry, transmission electron microscopy, and x-ray diffraction.
Crystallization of the alloy was established to result in the formation of a nanocrystalline structure consisting of three
phases. The domain structure and magnetic properties of amorphous and nanocrystalline samples were investigated using the
magnetooptic indicating film technique (MOIF) and a vibrating-sample magnetometer. The coercive force and the saturation magnetization
of the amorphous samples were found to be 1 Oe and 130 emu/g, respectively. It was shown that the formation of the nanocrystalline
structure entails a dramatic decrease in domain size (down to 1–4 μm) as compared to an amorphous sample (∼1 mm). Simultaneously,
a decrease in the saturation magnetization and a strong increase in the coercive force of the samples were observed.
__________
Translated from Fizika Tverdogo Tela, Vol. 46, No. 5, 2004, pp. 858–863.
Original Russian Text Copyright ? 2004 by Abrosimova, Aronin, Kabanov, Matveev, Molokanov. 相似文献