全文获取类型
收费全文 | 567295篇 |
免费 | 4538篇 |
国内免费 | 1362篇 |
专业分类
化学 | 288576篇 |
晶体学 | 8189篇 |
力学 | 28063篇 |
综合类 | 18篇 |
数学 | 73551篇 |
物理学 | 174798篇 |
出版年
2021年 | 5365篇 |
2020年 | 5815篇 |
2019年 | 6586篇 |
2018年 | 8928篇 |
2017年 | 9078篇 |
2016年 | 12417篇 |
2015年 | 6632篇 |
2014年 | 11170篇 |
2013年 | 25075篇 |
2012年 | 19705篇 |
2011年 | 23270篇 |
2010年 | 17526篇 |
2009年 | 17428篇 |
2008年 | 22046篇 |
2007年 | 21840篇 |
2006年 | 19928篇 |
2005年 | 17779篇 |
2004年 | 16526篇 |
2003年 | 14959篇 |
2002年 | 14874篇 |
2001年 | 15854篇 |
2000年 | 12188篇 |
1999年 | 9444篇 |
1998年 | 8246篇 |
1997年 | 8046篇 |
1996年 | 7454篇 |
1995年 | 6728篇 |
1994年 | 6715篇 |
1993年 | 6508篇 |
1992年 | 6884篇 |
1991年 | 7332篇 |
1990年 | 7030篇 |
1989年 | 6976篇 |
1988年 | 6718篇 |
1987年 | 6511篇 |
1986年 | 6264篇 |
1985年 | 7850篇 |
1984年 | 8317篇 |
1983年 | 6982篇 |
1982年 | 7288篇 |
1981年 | 6748篇 |
1980年 | 6415篇 |
1979年 | 6934篇 |
1978年 | 7257篇 |
1977年 | 7153篇 |
1976年 | 7067篇 |
1975年 | 6747篇 |
1974年 | 6614篇 |
1973年 | 6873篇 |
1972年 | 5042篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
B. Giner I. Gascón A. Villares C. Lafuente 《Journal of Thermal Analysis and Calorimetry》2006,83(3):735-745
The
relation between refractive index deviations and excess volumes for binary
mixtures formed by a cyclic ether and a haloalkane has been tested using several
methods: refractive index mixing rules and equations of state. Refractive
index deviations, excess volumes and molar refractions have been calculated
from experimental data of refractive indices and densities at two temperatures
298.15 and 313.15 K. Results obtained have been discussed in terms of intermolecular
interactions. Refractive indices were compared with those predicted by several
mixing rules. Excess volumes have also been correlated using several cubic
equations of state and finally a relation between parameter b
from equations of state and molar refraction has been provided. 相似文献
982.
Boric acid esters as thermal stabilizers and fungicidal additives for elastomers from natural rubber
New and previously synthesized boric acid esters were studied as thermal stabilizing and fungicidal additives to elastomers based on natural rubbers. 相似文献
983.
S. V. Usachev A. S. Osipov G. I. Kostrykina T. I. Irkhina N. B. Tantsova E. G. Fedorova 《Russian Journal of Applied Chemistry》2006,79(11):1890-1895
Variation of the molecular structure characteristics and properties of natural and 1,4-cis-polybutadiene rubbers (gel content, molecular weight, degree of branching of macromolecules, viscosity) in the course of their separate and joint mastication in the presence of dibenzoylaminodiphenyl sulfide as mastication accelerator or without it was studied. 相似文献
984.
985.
986.
Conclusion The reaction of 1-arylsulfamido-2-chloroethanes with diethylamine and aniline gives 1-arylsulfamido-2-aminoethanes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 943–946, April, 1987. 相似文献
987.
988.
A nonrelativistic deuteron wave function involving the D-wave state and having a correct asymptotic behavior is constructed on the basis of the experimentally measured deuteron charge form factor G C(q) and deuteron structure function A(q). The differential cross section for elastic deuteron-nucleus scattering is calculated by using this wave function and is found to agree with experimental data at an energy of 110 MeV. Integrated cross sections for various processes involving deuteron-nucleus interactions are also calculated. The distribution in the emission angle of the center of mass of the neutron-proton system produced in the diffractive dissociation of 110-MeV deuterons in the field of 208Pb nuclei is obtained. 相似文献
989.
Four relaxation processes and one ferroelectric-paraelectric phase transition are revealed in vinylidene fluoride-hexafluoropropylene copolymers with different ratios of the components in the temperature range from ?100 to 150°C. The relaxation process occurring at the lowest temperature is associated with the local mobility of the chains, whereas the relaxation process at a higher temperature is due to micro-Brownian motion of segments in the amorphous phase in the glass transition range. A smeared relaxor phase transition from the polar modification of the α phase of vinylidene fluoride units to the paraelectric phase is observed in the temperature range 50–70°C. At higher temperatures, there occurs an intensive relaxation process that can be attributed to space-charge relaxation or manifestation of the normal relaxation mode. 相似文献
990.
N. V. Khitrich I. I. Seifullina Yu. K. Epimakhov P. A. Ivanchenko 《Russian Journal of Applied Chemistry》2006,79(9):1514-1517
Kinetic features of radical polymerization of styrene initiated by tert-butyl perbenzoate in the presence of tris(N,N-dimethyldithiocarbamato)cobalt(III) (CoL3) and its adduct with iodine (CoL3 · 2I2) were studied. The optimal concentration ratios of the activators and tert-butyl perbenzoate, providing fast styrene polymerization at 338–368 K, were determined. 相似文献