全文获取类型
收费全文 | 8071篇 |
免费 | 194篇 |
国内免费 | 23篇 |
专业分类
化学 | 4931篇 |
晶体学 | 46篇 |
力学 | 146篇 |
数学 | 1535篇 |
物理学 | 1630篇 |
出版年
2023年 | 49篇 |
2022年 | 139篇 |
2021年 | 146篇 |
2020年 | 84篇 |
2019年 | 93篇 |
2018年 | 195篇 |
2017年 | 176篇 |
2016年 | 305篇 |
2015年 | 207篇 |
2014年 | 284篇 |
2013年 | 618篇 |
2012年 | 447篇 |
2011年 | 554篇 |
2010年 | 322篇 |
2009年 | 277篇 |
2008年 | 447篇 |
2007年 | 453篇 |
2006年 | 417篇 |
2005年 | 317篇 |
2004年 | 270篇 |
2003年 | 194篇 |
2002年 | 182篇 |
2001年 | 117篇 |
2000年 | 98篇 |
1999年 | 72篇 |
1998年 | 65篇 |
1997年 | 67篇 |
1996年 | 58篇 |
1995年 | 61篇 |
1993年 | 50篇 |
1992年 | 68篇 |
1991年 | 56篇 |
1990年 | 58篇 |
1989年 | 57篇 |
1988年 | 58篇 |
1987年 | 54篇 |
1986年 | 45篇 |
1985年 | 68篇 |
1984年 | 72篇 |
1983年 | 72篇 |
1982年 | 68篇 |
1981年 | 50篇 |
1980年 | 62篇 |
1979年 | 57篇 |
1978年 | 75篇 |
1977年 | 47篇 |
1976年 | 55篇 |
1975年 | 47篇 |
1974年 | 51篇 |
1973年 | 43篇 |
排序方式: 共有8288条查询结果,搜索用时 15 毫秒
981.
982.
Milojković-Opsenica Dusanka M. Lazarević Kristina Ivačković Vojkan Tešić Zivoslav Lj. 《平面色谱法杂志一现代薄层色谱法》2003,16(4):276-279
JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of nine frequently used water-soluble food dyes has been studied by TLC on RP-18 silica gel.... 相似文献
983.
Miroljub Jevtić 《Journal d'Analyse Mathématique》2003,91(1):123-141
A characterization of the functions fixed by a class of integral operators associated with hyperbolically-harmonic functions
is given. 相似文献
984.
985.
In this paper, we introduce the notion of Laplacian spectrum of an infinite countable graph in a different way than in the papers by B. Mohar. We prove some basic properties of this type of spectrum. The approach used is in line with our approach to the limiting spectrum of an infinite graph. The technique of the Laplacian spectrum of finite graphs is essential in this approach. 相似文献
986.
Sang Kyu Lee Byung‐Jun Jung Taek Ahn Young Kwan Jung Jeong‐Ik Lee In‐Nam Kang Jonghee Lee Jong‐Hwa Park Hong Ku Shim 《Journal of polymer science. Part A, Polymer chemistry》2007,45(15):3380-3390
A series of fluorene‐based copolymers composed of blue‐ and orange‐light‐emitting comonomers were synthesized through palladium‐catalyzed Suzuki coupling reactions. 9,9‐Dihexylfluorene and 2‐(2,6‐bis‐{2‐[1‐(9,9‐dihexyl‐9H‐fluoren‐2‐yl)‐1,2,3,4‐tetrahydroquinolin‐6‐yl]‐vinyl}‐pyran‐4‐ylidene)‐malononitrile (DCMF) were used as the blue‐ and orange‐light‐emitting chromophores, respectively. The resulting single polymers exhibited simultaneous blue (423/450 nm) and orange (580–600 nm) emissions from these two chromophores. By adjusting the fluorene and DCMF contents, white light emission could be obtained from a single polymer; a device with an ITO/PEDOT:PSS/polymer/Ca/Al configuration was found to exhibit pure white electroluminescence with Commission Internationale de L'Eclairage (CIE) coordinates of (0.33, 0.31), a maximum brightness of 1180 cd/m2, and a current efficiency of 0.60 cd/A. Furthermore, the white light emission of this device was found to be very stable with respect to variation of the driving voltage. The CIE coordinates of the device were (0.32, 0.29), (0.32, 0.29), and (0.33, 0.31) for driving voltages of 7, 8, and 10 V, respectively. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3380–3390, 2007 相似文献
987.
Ksenija Babić-Samardžija Norman Hackerman 《Journal of Solid State Electrochemistry》2005,9(7):483-497
The effect of a 1H-1,2,3-triazole, 1,2,3-benzotriazole and a number of substituted benzotriazoles, namely 1-hydroxybenzotriazole, 1H-benzotriazole-1-methanol and N-(1H-benzotriazol-1-ylmethyl)-formamide, have been investigated with respect to the corrosion of iron in 1 mol/l HCl and 1 mol/l HClO4. The Tafel extrapolation method, linear polarization resistance and electrochemical impedance spectroscopy illustrate the inhibiting effect of all of these compounds in both acids. They are better inhibitors in 1 mol/l HCl than in 1 mol/l HClO4. The changes of charge transfer resistance are also indicative for adsorption and inhibition of all of these compounds. This effect increases with time up to 16 h. An equivalent circuit is suggested as a model for the impedance. The adsorption of triazole-type of compounds in both acids follows a Langmuir isotherm. Molecular modeling was used to gain some insight, about structural and electronic effects in relation to the inhibiting efficiencies. 相似文献
988.
P. L. López-de-Alba L. López-Martínez Katarzyna Wróbel Kazimierz Wróbel J. Amador-Hernández 《Journal of Radioanalytical and Nuclear Chemistry》1997,220(2):167-171
A multivariate calibration method, Partial Least Squares Type 1 (PLS-1), is proposed for simultaneous spectrophotometric determination of uranium and thorium ions as their complexes with arsenazo III in hydrochloric acid medium. Several data characteristics are taking into account in order to minimize the optimum number of factors required for the construction of calibration model, while using various statistical criterions of selection. Finally, the evaluated calibration model is satisfactorily applied to determination of these ions in samples that resemble sulfuric acid leach solution obtained from a uranium ore. 相似文献
989.
Hrvoje Nikolić 《Foundations of Physics Letters》2006,19(6):553-566
Classical statistical particle mechanics in the configuration space can be represented by a nonlinear Schrödinger equation. Even without assuming the existence of deterministic particle trajectories, the resulting quantum-like statistical interpretation is sufficient to predict all measurable results of classical mechanics. In the classical case, the wave function that satisfies a linear equation is positive, which is the main source of the fundamental difference between classical and quantum mechanics. 相似文献
990.
A compatible statistical interpretation of a wave packet is proposed. De Broglian probabilities which unite wave and particle features of quantons are evaluated for free wave packets and Jor a superposition of wave packets. The obtained expressions provide a very plausible and physically appealing explanation of coherence in apparently incoherent beams and of the characteristic modulation of the momentum distribution, found recently in neutron interferometry combined with spectral filtering. Certain conclusions about dualism and objectivity in quantum domain are also derived. 相似文献