全文获取类型
收费全文 | 469285篇 |
免费 | 3563篇 |
国内免费 | 1217篇 |
专业分类
化学 | 223291篇 |
晶体学 | 7466篇 |
力学 | 25196篇 |
综合类 | 11篇 |
数学 | 66210篇 |
物理学 | 151891篇 |
出版年
2020年 | 3451篇 |
2019年 | 4110篇 |
2018年 | 12063篇 |
2017年 | 12557篇 |
2016年 | 10847篇 |
2015年 | 4906篇 |
2014年 | 7527篇 |
2013年 | 17246篇 |
2012年 | 16362篇 |
2011年 | 25245篇 |
2010年 | 17190篇 |
2009年 | 17405篇 |
2008年 | 22728篇 |
2007年 | 25422篇 |
2006年 | 13647篇 |
2005年 | 16724篇 |
2004年 | 13765篇 |
2003年 | 12874篇 |
2002年 | 11283篇 |
2001年 | 11637篇 |
2000年 | 8985篇 |
1999年 | 6777篇 |
1998年 | 5717篇 |
1997年 | 5715篇 |
1996年 | 5501篇 |
1995年 | 4913篇 |
1994年 | 4931篇 |
1993年 | 4883篇 |
1992年 | 5289篇 |
1991年 | 5494篇 |
1990年 | 5207篇 |
1989年 | 5225篇 |
1988年 | 5193篇 |
1987年 | 5073篇 |
1986年 | 4848篇 |
1985年 | 6369篇 |
1984年 | 6654篇 |
1983年 | 5389篇 |
1982年 | 5606篇 |
1981年 | 5484篇 |
1980年 | 5240篇 |
1979年 | 5650篇 |
1978年 | 5696篇 |
1977年 | 5692篇 |
1976年 | 5813篇 |
1975年 | 5334篇 |
1974年 | 5300篇 |
1973年 | 5472篇 |
1972年 | 3972篇 |
1971年 | 3446篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
961.
D. N. Emel’yanov N. V. Volkova O. I. Sheronova Z. G. Chernorukova 《Russian Journal of Applied Chemistry》2006,79(8):1354-1359
The process of preservation of newspaper with aqueous solutions and dispersions of acrylic copolymers is considered from the instant of impregnation till removal of the polymeric preservative from paper. 相似文献
962.
S.A. Masti A.K. Sharma P.N. Vasambekar A.S. Vaingankar 《Journal of magnetism and magnetic materials》2006
Magnetization and permeability of polycrystalline ferrites with general formula CdxMg1−xFe2−yCryO4 (x=0, 0.2, 0.4, 0.6, 0.8, 1.0; y=0, 0.05 and 0.10) were studied. Study of saturation magnetization reveals that the Neel's two-sublattice model exists upto x=0.4, for y=0, 0.05 and 0.1 and a three-sublattice model (YK-model) is predominant for x>0.4 and y=0, 0.05 and 0.10. The saturation magnetization and magnetic moment were found to decrease with the increase in Cr3+ contents, which is attributed to the dilution of B–B site interaction. Variation of initial permeability with temperature revealed the long-range ferromagnetic ordering in the compounds with x=0.4. The sample with x?0.4 and y=0, 0.05 and 0.10 showed peaking behavior near Curie temperature, which is attributed to the decrease of anisotropy constant K1 to zero. Low-frequency dispersion of initial permeability suggests domain wall displacement. Addition of Cd2+ resulted in a sharp decrease in Curie temperature. With the addition of Cr3+, initial permeability was found to decrease. 相似文献
963.
N. Hegyvári 《Acta Mathematica Hungarica》1989,53(1-2):149-154
964.
Correlation between the particles from the proton-nucleus interactions in emulsion at 70 GeV/c is presented through the study of the rapidity gap analysis and compared with the two-particle rapidity correlations. It is observed that the strength of correlation decreases as the size of cluster increases. Asymmetry between the forward and backward components were also studied.Authors are thankful to Prof. K. D. Tolstov, JINR, Dubna, USSR for sending the exposed emulsion plates. Thanks are also due to UGC for financial assistance. We sincerely acknowledge the encouragement from Prof. T. Roy. 相似文献
965.
This paper presents results of studies on dc electrical conductivity and transference number measurements on potassium bromate
(KBrO3) complexed polyvinyl chloride (PVC) films prepared by solution cast technique. Temperature dependence of dc electrical conductivity
and transference number data indicated the dominance of ion type charge transport in these specimens. The magnitude of conductivity
increased with increase in concentration of the salt and temperature. Using this (PVC + KBrO3) electrolyte, solid-state electrochemical cells were fabricated, and their discharge profiles were studied under a constant
load of 100 kΩ. Several cell profiles such as open circuit voltage, short circuit current, power density, and energy density
associated with these cells were evaluated and were reported. The features of complexation of the electrolytes were studied
by X-ray diffraction and Fourier transform infrared spectroscopy.
Paper presented at the Third International Conference on Ionic Devices (ICID 2006), Chennai, Tamilnadu, India, Dec. 7–9, 2006 相似文献
966.
A. G. Zhdanov A. K. Zvezdin A. P. Pyatakov T. B. Kosykh D. Viehland 《Physics of the Solid State》2006,48(1):88-95
The specific features of the “incommensurate-commensurate” phase transitions induced by a magnetic field in multiferroics
(materials with coexisting magnetic and electric ordering) are considered. These materials are ferroelectromagnets, for example,
bismuth ferrite BiFeO3 and BiFeO3-based compounds, which have spatially modulated spin structures. It is shown that the interaction between the electric and
magnetic subsystems of the multiferroic material can lead to an electric-field-induced shift of the critical magnetic field
corresponding to the transition from a spatially modulated state to a homogeneous antiferromagnetic state. According to the
theoretical estimates obtained for material parameters characteristic of the bismuth ferrite, this shift is of the order of
0.5 T in an electric field of 50 kV/cm. The phase diagrams are constructed in the “electric field-magnetic field” coordinates.
The results of calculations performed in the harmonic incommensurate structure approximation are compared with the exact soliton
solution. 相似文献
967.
968.
I. G. Silinskaya A. V. Novoselova Yu. N. Sazanov A. V. Gribanov I. N. Serov V. I. Margolin 《Russian Journal of Applied Chemistry》2006,79(8):1378-1380
Mechanisms of orientation for the solutions of polyacrylonitrile synthesized under conditions of radical and anionic polymerization were studied. The effect of the fractal-matrix structuring agent developed by the AIRES foundation on the correlation parameters of the solution density and average squared fluctuation polarizability, which can be used to determine how the supramolecular structure changes by “self-orientation” and “induced orientation” mechanisms, was analyzed. 相似文献
969.
A. P. Suponina L. G. Kolzunova M. A. Karpenko 《Russian Journal of Applied Chemistry》2006,79(6):924-929
The effect of coatings based on a copolymer of acrylamide, N,N′-methylenebisaxcrylamide and formaldehyde deposited by electrochemical polymerization on the corrosion resistance of 08Kh18N10T stainless steel (field studies at sea) and low-carbon steel (laboratory experiments) was examined. 相似文献
970.
T. Yu. Gumerov A. F. Dobrynina R. A. Yusupov V. P. Barabanov 《Russian Journal of Applied Chemistry》2006,79(12):1935-1939
The behavior of real disperse systems with organic impurities was examined under conditions of destabilization by inorganic coagulants. A number of physicochemical methods of analysis and a simulation method were used to identify the character and type of the complexes formed and to calculate their stability constants. 相似文献