全文获取类型
收费全文 | 4539篇 |
免费 | 108篇 |
国内免费 | 30篇 |
专业分类
化学 | 2326篇 |
晶体学 | 61篇 |
力学 | 200篇 |
综合类 | 5篇 |
数学 | 1042篇 |
物理学 | 1043篇 |
出版年
2023年 | 21篇 |
2022年 | 58篇 |
2021年 | 78篇 |
2020年 | 72篇 |
2019年 | 118篇 |
2018年 | 178篇 |
2017年 | 173篇 |
2016年 | 205篇 |
2015年 | 139篇 |
2014年 | 206篇 |
2013年 | 495篇 |
2012年 | 269篇 |
2011年 | 285篇 |
2010年 | 259篇 |
2009年 | 209篇 |
2008年 | 249篇 |
2007年 | 251篇 |
2006年 | 162篇 |
2005年 | 235篇 |
2004年 | 224篇 |
2003年 | 111篇 |
2002年 | 63篇 |
2001年 | 46篇 |
2000年 | 55篇 |
1999年 | 42篇 |
1998年 | 36篇 |
1997年 | 33篇 |
1996年 | 33篇 |
1995年 | 26篇 |
1994年 | 15篇 |
1992年 | 12篇 |
1991年 | 14篇 |
1990年 | 10篇 |
1989年 | 14篇 |
1988年 | 18篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 19篇 |
1984年 | 16篇 |
1983年 | 14篇 |
1982年 | 16篇 |
1981年 | 22篇 |
1980年 | 14篇 |
1979年 | 16篇 |
1977年 | 10篇 |
1976年 | 17篇 |
1975年 | 9篇 |
1974年 | 13篇 |
1973年 | 11篇 |
1968年 | 11篇 |
排序方式: 共有4677条查询结果,搜索用时 15 毫秒
51.
Mustafa Şenyel T. Raci Sertbakan Güneş Kürkçüoğ Ergün Kasap Ziya Kantarci 《Journal of inclusion phenomena and macrocyclic chemistry》2001,39(1-2):175-180
Three Hofmann-diaminododecane-type clathrates of the form M(1,12-diaminododecane) Ni(CN)4G (M = Co, Ni or Cd; G = benzene, naphthalene, anthracene, phenanthrene or biphenyl) have been prepared in powder form. The 1,12-diaminododecane molecules in the host lattice permit the inclusion of bulky guest molecules. The spectral features suggest that these compounds are similar in structure to the other Hofmann-diam-type clathrates. 相似文献
52.
K. Kaya K. Fuke S. Nonose N. Kikuchi 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1989,12(1-4):571-573
Aluminum clusters were generated by a laser vaporization method. Ionization potential of Al2 was found to be lower than that of Al. In the reaction with oxygen at high concentration, the mixed cluster Al9O7 survives predominantly as a stable cluster. Ammonia was found to be adsorbed weakly on the Aln surface. 相似文献
53.
N. Ibriş J. Mirza-Rosca A. Santana T. Vişan 《Journal of Solid State Electrochemistry》2002,6(2):119-125
The corrosion and passivation of Zn powder particles dispersed in a paste electrode immersed in 0.5 M Na2SO4 and 5×10–3 M Na2HPO4 solutions were studied mainly by electrochemical impedance spectroscopy. The role played by diffusion in the mechanism of
anodic oxidation of zinc powder particles has been shown. It was demonstrated that the anodic reactionof Zn powder in neutral
or near neutral media involves at least two adsorbed intermediates. By simulating the porous structure of the electrode, some
information about porous nature of zinc electrode could be extracted.
Electronic Publication 相似文献
54.
Smetanina O. F. Kuznetzova T. A. Denisenko V. A. Pivkin M. V. Khudyakova Yu. V. Gerasimenko A. V. Popov D. Yu. Il"in S. G. Elyakov G. B. 《Russian Chemical Bulletin》2001,50(12):2463-2465
A pentacyclic tritepenoid, 3-methoxyolean-18-ene (miliacin), was isolated for the first time from the marine fungus Chaetomium olivaceum. Its structure was determined on the basis of 2D NMR spectroscopy and X-ray diffraction data. 相似文献
55.
The fluorescence spectrum of pyrazine vapour and the Raman spectra of liquid pyrazine excited at various wavelengths were observed. The appearance of the long progression of the hydrogen bending vibration ν5 (b2g) in the fluorescence spectrum and a remarkable preresonance effect of the Raman line of the same vibration confirm the theoretical prediction given by Albrecht. 相似文献
56.
Manganese in vitamin-minerals tablets was determined by solid sampling electrothermal atomic absorption spectrometry (SS-ETAAS) using three different calibration methods, namely calibration against aqueous standards, standard addition with aqueous standards on solid samples and calibration against solid certified standards. Samples were only finely ground and introduced directly into the furnace by means of solid autosampler system without any dissolving process. Effects of different calibration techniques, temperatures and heating rates of atomization and pyrolysis steps on the accuracy and precision of the analyte elements were investigated. After optimization of the experimental parameters, there is good agreement (at 95% confidence level) between the results obtained by solid sampling and those obtained by acid digestion of samples. 相似文献
57.
Annals of Global Analysis and Geometry - We give an elementary and self-contained proof of the uniformization theorem for noncompact simply connected Riemann surfaces. 相似文献
58.
Metin Başarir 《Periodica Mathematica Hungarica》1995,30(3):177-181
In this paper, necessary and sufficient conditions that the real doubly infinite matrixA sums every strongly almost convergent double sequence, leaving the limit invariant, have been determined. 相似文献
59.
I. Muzyčenková V. Kellnerová M. Koneracká P. Kopčanský M. Antalík J. Ďurišin 《Czechoslovak Journal of Physics》1995,45(9):727-734
The encapsulation of fine magnetite particles of 10 nm size and marker ANS within asolectin vesicles has been made by sonication of the mixture in water. For the proof of encapsulation of magnetite in vesicles the electron microscope and spectrofluoriphotometer technique were used. The theory for the calculation of the magnetic force acting on the system consisted of non-capsulated magnetic particles dispersed in water and magnetic vesicles was developed.This work was supported by the Slovak Academy of Sciences within the framework of Project GAV No. 1361. 相似文献
60.