全文获取类型
收费全文 | 258042篇 |
免费 | 2768篇 |
国内免费 | 652篇 |
专业分类
化学 | 143774篇 |
晶体学 | 3472篇 |
力学 | 9049篇 |
综合类 | 7篇 |
数学 | 31766篇 |
物理学 | 73394篇 |
出版年
2021年 | 2184篇 |
2020年 | 2613篇 |
2019年 | 2856篇 |
2018年 | 4081篇 |
2017年 | 3931篇 |
2016年 | 5820篇 |
2015年 | 3677篇 |
2014年 | 5088篇 |
2013年 | 12069篇 |
2012年 | 9546篇 |
2011年 | 10923篇 |
2010年 | 7713篇 |
2009年 | 7349篇 |
2008年 | 10330篇 |
2007年 | 10171篇 |
2006年 | 9413篇 |
2005年 | 8749篇 |
2004年 | 7725篇 |
2003年 | 6940篇 |
2002年 | 6613篇 |
2001年 | 6700篇 |
2000年 | 5476篇 |
1999年 | 4057篇 |
1998年 | 3465篇 |
1997年 | 3432篇 |
1996年 | 3351篇 |
1995年 | 2700篇 |
1994年 | 2871篇 |
1993年 | 2863篇 |
1992年 | 3020篇 |
1991年 | 3013篇 |
1990年 | 2937篇 |
1989年 | 2854篇 |
1988年 | 2782篇 |
1987年 | 2739篇 |
1986年 | 2658篇 |
1985年 | 3436篇 |
1984年 | 3567篇 |
1983年 | 2855篇 |
1982年 | 3110篇 |
1981年 | 3005篇 |
1980年 | 2756篇 |
1979年 | 2957篇 |
1978年 | 3080篇 |
1977年 | 3088篇 |
1976年 | 3090篇 |
1975年 | 2909篇 |
1974年 | 2879篇 |
1973年 | 3048篇 |
1972年 | 2009篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
951.
I. I. Milman E. V. Moiseykin S. V. Nikiforov S. G. Mikhailov V. I. Solomonov 《Radiation measurements》2004,38(4-6):443
The spectra of pulsed cathodoluminescence (PCL) and thermoluminescence (TL) in TLD-500 detectors, which were exposed to a strong beam from a pulsed electron accelerator, have been studied. Additional bands in the PCL spectrum and new peaks in the TL curves, which are due to impurity ions, have been revealed. Luminescence bands of F- and F+-centers cannot be used in the dosimetry of strong electron beams using TLD-500 detectors because of the saturation of dose dependence and the decrease in the TL yield. It is shown that high doses from these beams can be measured by recording TL in the luminescence band of impurity titanium ions. 相似文献
952.
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
953.
The effective dielectric, piezoelectric, and elastic constants of two-phase macroscopically piezoactive 3-0 and 3-3 composites
are calculated. It is assumed that one of the components is a polarized ferroelectric ceramic material and the other is an
inactive material with variable elastic properties. The limiting case when the elastic compliances of the inactive material
tend to infinity (porous ferroelectric ceramics) is considered. The adequacy of this model to production technologies of piezoelectric
composites is discussed. Computational results are compared with experimental data. 相似文献
954.
A new formula that relates the acoustic Grüneisen parameter to the Poisson ratio is suggested on the basis of the previously derived expression for this parameter. 相似文献
955.
E. E. Sirotkina A. I. Khlebnikov N. A. Domina A. V. Domin 《Russian Physics Journal》2004,47(11):1134-1138
Intensities of principal diffraction maxima for a phase reflection diffraction grating with a rectangular groove profile were calculated by the Fresnel method, using a special algorithm. The procedure under consideration enables us to perform high-efficiency calculations of diffracted-beam characteristics and can be used extensively to optimize diffraction-grating parameters.__________This revised version was published online in May 2005 with a correction on affiliation.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 38–41, November 2004. 相似文献
956.
Two nonstationary cosmological models with rotation are constructed for the Bianchi II metric within the Einstein gravitation theory. The first model is filled with a co-moving perfect liquid and radiation field and is characterized by nonzero expansion, rotation, and acceleration. A perfect liquid which is not co-moving with a reference system is a source of gravitation for the second model. The second model corresponds to nonzero rotations and accelerations. 相似文献
957.
E. V. Glukhova 《Russian Physics Journal》2004,47(2):154-159
In the present paper, the main probabilistic characteristics (the mathematical expectation, variance, and correlation function) of the amount of harmful substances in anthropogenic formations are calculated under the stationary conditions when the stream of these substances is a recurrent stream of events. 相似文献
958.
959.
960.