全文获取类型
收费全文 | 298586篇 |
免费 | 6939篇 |
国内免费 | 5243篇 |
专业分类
化学 | 165628篇 |
晶体学 | 4297篇 |
力学 | 13563篇 |
综合类 | 328篇 |
数学 | 34324篇 |
物理学 | 92628篇 |
出版年
2022年 | 2775篇 |
2021年 | 3601篇 |
2020年 | 3994篇 |
2019年 | 4432篇 |
2018年 | 5541篇 |
2017年 | 5347篇 |
2016年 | 7132篇 |
2015年 | 4525篇 |
2014年 | 6843篇 |
2013年 | 13484篇 |
2012年 | 11330篇 |
2011年 | 13007篇 |
2010年 | 9660篇 |
2009年 | 9555篇 |
2008年 | 11970篇 |
2007年 | 11672篇 |
2006年 | 10871篇 |
2005年 | 9808篇 |
2004年 | 8708篇 |
2003年 | 7893篇 |
2002年 | 7878篇 |
2001年 | 8071篇 |
2000年 | 6378篇 |
1999年 | 4902篇 |
1998年 | 4354篇 |
1997年 | 4169篇 |
1996年 | 3945篇 |
1995年 | 3274篇 |
1994年 | 3440篇 |
1993年 | 3413篇 |
1992年 | 3518篇 |
1991年 | 3624篇 |
1990年 | 3517篇 |
1989年 | 3429篇 |
1988年 | 3255篇 |
1987年 | 3185篇 |
1986年 | 3106篇 |
1985年 | 3807篇 |
1984年 | 3990篇 |
1983年 | 3252篇 |
1982年 | 3494篇 |
1981年 | 3278篇 |
1980年 | 3051篇 |
1979年 | 3358篇 |
1978年 | 3516篇 |
1977年 | 3530篇 |
1976年 | 3582篇 |
1975年 | 3371篇 |
1974年 | 3368篇 |
1973年 | 3510篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
181.
Influence of the skin effect on the absorption of electromagnetic radiation by a fine metal particle
The cross section of absorption of electromagnetic radiation by a fine spherical metal particle is calculated. The influence of the skin effect on the absorption cross-section is estimated for an arbitrary ratio between the free path and size of the particle. The results of this work are compared with those obtained earlier in the framework of classical electrodynamics. It is shown that taking into account the kinetic effects modifies essentially the known data for the skin effect in a spherical particle. 相似文献
182.
E. L. Pankratov 《Technical Physics》2004,49(1):114-118
The establishment of the steady-state dopant profile in a medium with a time-variable diffusion coefficient is considered
within the approach proposed previously for estimating mass-and heat-transfer time characteristics. It is shown that the time
it takes for the equilibrium concentration to set in may be increased or decreased by appropriately choosing the law of variation
of the diffusion coefficient. 相似文献
183.
A theory of a planar disk-shaped RF plasma source under anomalous skin effect conditions is developed. In the absence of an external magnetic field, such conditions are satisfied for transverse electromagnetic waves with phase velocities below the electron thermal velocity, and, in the presence of this field, they are satisfied for electron cyclotron waves with frequencies corresponding to the resonant absorption line. For each of these cases, the RF field power deposited in a plasma with given parameters is determined and the equivalent plasma resistance is calculated. 相似文献
184.
Dineykhan M. Zhaugasheva S. A. Kozhamkulov T. A. Petrov E. V. 《Russian Physics Journal》2004,47(12):1250-1260
The mass spectrum of a coupled state is analytically determined. The mechanism of production of a constituent mass of particles forming a coupled state is explained. The change of the coupled state and constituent particle component masses attendant to changes of the coupling constant is analyzed. The mass spectrum of a two-gluon glueball is determined with allowance for spin-orbital and spin-spin interactions.__________Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 33–41, December, 2004. 相似文献
185.
186.
The study of the effect of a perfectly conducting plane placed at a certain distance from the surface of a potassium niobate crystal on the characteristics of the generalized Rayleigh and Gulyaev-Bleustein surface waves is continued. In addition, the effect of an infinitely thin conducting layer applied to the surface of the piezoelectric on the characteristics of these waves is analyzed. It is found that a variation in the conductance of this layer can produce a result that completely differs from the result obtained when a perfectly conducting plane is moved toward the surface, although the extreme states of these actions (electrically open and short-circuited surfaces) are identical. A possible physical explanation of this difference is proposed. 相似文献
187.
The magnetic absorption cross section of a small spherical particle with a dielectric core and a metallic shell is calculated. The general case is considered when the ratio of the radius of the dielectric core to the total radius of the particle may take arbitrary values. The condition of specular-diffuse reflection of conduction electrons from the surfaces of the metal layer of the particle is chosen as the boundary conditions of the problem. The limit cases are considered, and the results are discussed. 相似文献
188.
S. A. Sadovsky Yu. V. Kharlov A. L. S. Angelis E. Gładysz-Dziaduś V. L. Korotkikh G. Mavromanolakis A. D. Panagiotou 《Physics of Atomic Nuclei》2004,67(2):396-405
A phenomenological model for describing the production of Centauro events in relativistic heavy-ion collisions is discussed. The model provides quantitative predictions for kinematical variables, for the baryon number, and for the masses of a Centauro fireball and of its decay products. A Centauro fireball decays predominantly into nucleons, strange hyperons, and possibly strangelets. Centauro events in Pb + Pb collisions at the LHC energy are simulated for the CASTOR detector. The signatures of these events are discussed in detail. 相似文献
189.
A. Yu. Anisimov 《Physics of Atomic Nuclei》2004,67(3):640-647
We provide a detailed numerical study of the influence of thermal effects on the original picture of the Affleck-Dine baryogenesis. These effects are found to modify the results greatly in some cases. We estimate the baryon/entropy ratio and provide numerical results on the typical behavior of the charge as a function of the strength of the potential and other parameters. 相似文献
190.
Jie Da Thieo E. Hogen‐Esch 《Journal of polymer science. Part A, Polymer chemistry》2004,42(2):360-373
The synthesis is reported of copolymers of N,N‐dimethylacrylamide (DMA) and methacrylates containing 2,2′‐dihydroperfluorodecanoyl (RF) groups separated from the methacrylate by long polyethylene glycol (PEG) tether groups (between 1000 and 14,000 Da). At concentrations of between 1 and 8 wt % the copolymers with macromonomer contents of 1 mol % or less give gels in organic solvents such as dioxane, THF, or methanol, as well as in water. Given the low molecular weights, this indicates very efficient association of very low numbers of RF groups. Association and gel formation is enormously enhanced in the presence of longer PEG tethers. This is consistent with smaller poly(N,N,‐dimethylacrylamide) (PDMA) intermolecular excluded volume effects that are mediated by the longer PEG tethers and possibly by the incompatibility of PEG and PDMA that may lead to the formation of PEG microdomains. This increases the local concentrations of the RF groups in the PEO domains that are not diluted by the PDMA chains, as would be the case in the absence of PEG tethers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 360–373, 2004 相似文献