全文获取类型
收费全文 | 420115篇 |
免费 | 5003篇 |
国内免费 | 1224篇 |
专业分类
化学 | 230007篇 |
晶体学 | 6575篇 |
力学 | 16544篇 |
综合类 | 22篇 |
数学 | 47192篇 |
物理学 | 126002篇 |
出版年
2020年 | 3842篇 |
2019年 | 4161篇 |
2018年 | 5437篇 |
2017年 | 5459篇 |
2016年 | 8082篇 |
2015年 | 4967篇 |
2014年 | 7634篇 |
2013年 | 18959篇 |
2012年 | 14041篇 |
2011年 | 16891篇 |
2010年 | 12080篇 |
2009年 | 11756篇 |
2008年 | 15728篇 |
2007年 | 15585篇 |
2006年 | 14570篇 |
2005年 | 13208篇 |
2004年 | 11856篇 |
2003年 | 10771篇 |
2002年 | 10336篇 |
2001年 | 11695篇 |
2000年 | 9074篇 |
1999年 | 6881篇 |
1998年 | 5713篇 |
1997年 | 5693篇 |
1996年 | 5453篇 |
1995年 | 4830篇 |
1994年 | 4812篇 |
1993年 | 4738篇 |
1992年 | 5465篇 |
1991年 | 5298篇 |
1990年 | 5149篇 |
1989年 | 5182篇 |
1988年 | 5096篇 |
1987年 | 5090篇 |
1986年 | 4836篇 |
1985年 | 6342篇 |
1984年 | 6472篇 |
1983年 | 5138篇 |
1982年 | 5493篇 |
1981年 | 5430篇 |
1980年 | 5060篇 |
1979年 | 5534篇 |
1978年 | 5634篇 |
1977年 | 5748篇 |
1976年 | 5586篇 |
1975年 | 5171篇 |
1974年 | 5108篇 |
1973年 | 5140篇 |
1972年 | 3474篇 |
1967年 | 3421篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
V. A. Sadovnichy V. V. Alexandrov E. Soto T. B. Alexandrova T. G. Astakhova R. Vega N. V. Kulikovskaya V. I. Kurilov S. S. Migunov N. E. Shulenina 《Journal of Mathematical Sciences》2007,146(3):5938-5947
A mathematical model of the system composed of two sensors, the semicircular canal and the sacculus, is suggested. The model
is described by three lines of blocks, each line of which has the following structure: a biomechanical block, a mechanoelectrical
transduction mechanism, and a block describing the hair cell ionic currents and membrane potential dynamics. The response
of this system to various stimuli (head rotation under gravity and falling) is investigated. Identification of the model parameters
was done with the experimental data obtained for the axolotl (Ambystoma tigrinum) at the Institute of Physiology, Autonomous
University of Puebla, Mexico. Comparative analysis of the semicircular canal and sacculus membrane potentials is presented.
__________
Translated from Fundamentalnaya i Prikladnaya Matematika, Vol. 11, No. 7, pp. 207–220, 2005. 相似文献
992.
Single-particle matrix elements of nucleon transfer were calculated by the Woods-Saxon potential wave functions. The results
are compared with the ones calculated by the spherical-well approximation. The eligibility of the approximation of the mean
field of nuclei by the spherical well to study the initial stage of nuclear reactions at heavy-ion collisions is demonstrated.
The text was submitted by the authors in English. 相似文献
993.
We present a study of the temporal compression of nanosecond laser pulses resulting from the coherent control peculiarities of the propagation dynamics in a regime of electromagnetically induced transparency. We describe the general theoretical framework and discuss the crucial conditions required in order to experimentally realize such a temporal compression scheme. A proof-of-concept experimental realization of a scheme of this type in a sample of hot sodium vapors is currently being implemented: we describe in detail the experimental setup designed for this purpose. 相似文献
994.
The dynamical Casimir effect is analyzed in the framework of the S-matrix formulation for a one-dimensional cavity that exhibits contraction at a constant rate over a finite time interval. The exact solution to the problem is presented. It is demonstrated that the efficiency of the creation of pairs nonmonotonically depends on the contraction time. This is due to the fact that the particles are only created at the moments corresponding to the acceleration and stopping of the moving boundary, so that the contributions of these processes on the number of the created particles interfere with each other. The parameters that correspond to the optimal creation of pairs and the stability of a vacuum are presented. The effect of the finiteness of the cavity-boundary acceleration on the results obtained is studied. 相似文献
995.
Yu. V. Kaletina V. M. Schastlivtsev E. A. Fokina 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(12):1667-1673
The effect of magnetic treatment on the isothermal martensitic transformation in the Fe-24% Ni-4% Mn alloy has been investigated. The martensitic transformation in a dc magnetic field at liquid-helium temperature has been analyzed. 相似文献
996.
V. I. Zubkov I. S. Shulgunova A. V. Solomonov M. Geller A. Marent D. Bimberg A. E. Zhukov E. S. Semenova V. M. Ustinov 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(1):106-108
In this work, charge-carrier capture by an array of self-assembled InAs/GaAs quantum dots was directly observed for the first time by capacitance recharge. It is proposed to process the obtained transient-capture data by a similar method to that used for emission, by the box-car method. The capture activation energies are determined and compared with the emission activation energies. 相似文献
997.
L. A. Bityutskaya V. V. Distler V. V. Kryachko M. A. Yudovskaya M. V. Grechkina E. V. Bogatikov 《Physics of the Solid State》2007,49(7):1382-1386
Nanostructuring of natural isoferroplatinum crystals is revealed by atomic-force microscopy for the first time. Typical scales of ~30, 50, and 100 nm are determined and the self-affine character of their relation is established using a wavelet analysis. 相似文献
998.
Ph. Komninou Th. Kehagias A. Delimitis G.P. Dimitrakopulos J. Kioseoglou E. Dimakis A. Georgakilas Th. Karakostas 《Superlattices and Microstructures》2004,36(4-6):509
The structural properties of InN thin films, grown by rf plasma-assisted molecular beam epitaxy on Ga-face GaN/Al2O3(0001) substrates, were investigated by means of conventional and high resolution electron microscopy. Our observations showed that a uniform InN film of total thickness up to 1 μm could be readily grown on GaN without any indication of columnar growth. A clear epitaxial orientation relationship of , was determined. The quality of the InN film was rather good, having threading dislocations as the dominant structural defect with a density in the range of 109–1010 cm−2. The crystal lattice parameters of wurtzite InN were estimated by electron diffraction analysis to be a=0.354 nm and c=0.569 nm, using Al2O3 as the reference crystal. Heteroepitaxial growth of InN on GaN was accomplished by the introduction of a network of three regularly spaced misfit dislocation arrays at the atomically flat interface plane. The experimentally measured distance of misfit dislocations was 2.72 nm. This is in good agreement with the theoretical value derived from the in-plane lattice mismatch of InN and GaN, which indicated that nearly full relaxation of the interfacial strain between the two crystal lattices was achieved. 相似文献
999.
Sanzhizhapov D. B. Tonevitskii Yu. V. Mognonov D. M. Doroshenko Yu. E. 《Russian Journal of Applied Chemistry》2003,76(4):619-622
New polyimidates were prepared from bisphenols and mono- and dicarboxylic acid imidoyl chlorides. The structures of the polymers were determined, and their physicochemical, chemical, and thermal properties were studied. The possibility of preparing film and compression materials with good mechanical characteristics from these polymers was examined. 相似文献
1000.
E. B. Postnikov 《Journal of Experimental and Theoretical Physics》2007,105(3):652-654
It is shown that time-scale synchronization of chaotic systems with ill-defined conventional phase is achieved by using wavelet transforms with center frequencies above a certain threshold value. It is found that the possibility of synchronization detection by introducing a wavelet phase is related to diffusion averaging of the analyzed signals. 相似文献