全文获取类型
收费全文 | 346129篇 |
免费 | 3674篇 |
国内免费 | 2609篇 |
专业分类
化学 | 176684篇 |
晶体学 | 5402篇 |
力学 | 18339篇 |
综合类 | 168篇 |
数学 | 41769篇 |
物理学 | 110050篇 |
出版年
2021年 | 3553篇 |
2020年 | 3706篇 |
2019年 | 4574篇 |
2018年 | 6302篇 |
2017年 | 6371篇 |
2016年 | 8166篇 |
2015年 | 4280篇 |
2014年 | 7563篇 |
2013年 | 14753篇 |
2012年 | 11961篇 |
2011年 | 14030篇 |
2010年 | 11344篇 |
2009年 | 11539篇 |
2008年 | 13287篇 |
2007年 | 12955篇 |
2006年 | 11604篇 |
2005年 | 10232篇 |
2004年 | 9680篇 |
2003年 | 8736篇 |
2002年 | 8965篇 |
2001年 | 9745篇 |
2000年 | 7222篇 |
1999年 | 5512篇 |
1998年 | 4871篇 |
1997年 | 4746篇 |
1996年 | 4359篇 |
1995年 | 3851篇 |
1994年 | 3898篇 |
1993年 | 3863篇 |
1992年 | 4108篇 |
1991年 | 4468篇 |
1990年 | 4320篇 |
1989年 | 4392篇 |
1988年 | 4167篇 |
1987年 | 4191篇 |
1986年 | 3918篇 |
1985年 | 5013篇 |
1984年 | 5056篇 |
1983年 | 4297篇 |
1982年 | 4361篇 |
1981年 | 4218篇 |
1980年 | 3899篇 |
1979年 | 4466篇 |
1978年 | 4586篇 |
1977年 | 4771篇 |
1976年 | 4843篇 |
1975年 | 4517篇 |
1974年 | 4387篇 |
1973年 | 4634篇 |
1972年 | 3643篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
181.
N. S. Oliveira J. Dorgan J. A. P. Coutinho A. Ferreira J. L. Daridon I. M. Marrucho 《Journal of Polymer Science.Polymer Physics》2007,45(5):616-625
The sorption of carbon dioxide in glassy Poly(lactic acid) (PLA) films was studied by quartz crystal microbalance (QCM) at high pressures. Two thermal treatments, melted and quenched, were performed in PLA with two different L:D contents, 80:20 and 98:2, films and compared with a third thermal protocol, annealed, and used in a previous work. The results obtained show that for pressures higher than 2 MPa, the carbon dioxide solubility is larger in PLA 80:20 than in PLA 98:2, indicating that the L:D plays a dominant role on this property. The thermal treatments only affect the gas solubility in PLA 98:2. Sorption isotherms at temperatures 303, 313, and 323 K, below the glass transition temperature of the polymer, and pressures up to 5 MPa were measured and analyzed with three different models, the dual‐mode sorption model, the Flory–Huggins equation, and a modified dual‐mode sorption model where the Henry's law term was substituted by the Flory–Huggins equation. This last model performs especially well for CO2 in PLA 80:20, due to the convex upward curvature of the solubility isotherms for that system. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 616–625, 2007 相似文献
182.
183.
This article describes the technique of fast atom bombardment mass spectrometry (FAB MS) and its applications to the analysis of organometallic and coordination complexes. Sections on ion generation and matrices are followed by a Periodic Group-based review of FAB MS results obtained from Transition Metal and Main Group compounds, organometallic cluster carbonyls and their derivatives, and salts of poly-oxo-anions. The literature has been surveyed from 1981 to approximately mid-1986. 相似文献
184.
185.
N. G. Kanev 《Acoustical Physics》2006,52(5):571-575
Effect of errors of different origin on the efficiency of sound absorption by a local active absorber is investigated. Degradation of the efficiency of absorption because of the errors is shown to be minimal in the case when the controller does not detect the field of the secondary radiator. Estimates of admissible errors are presented. Several active absorber configurations in which the radiator does not affect the receiver are considered. 相似文献
186.
187.
Kryazhimskiy A. V. Maksimov V. I. 《Proceedings of the Steklov Institute of Mathematics》2006,253(1):S168-S184
A problem of guaranteeing control for a system of parabolic equations is considered. A solving algorithm based on the combination of real time reconstruction processes and feedback control is designed. 相似文献
188.
N. A. Lockerbie 《General Relativity and Gravitation》2006,38(3):533-536
This paper is in answer to the comment on the GRG paper: Lockerbie N.A. Gen. Rel. Grav. 36, 593 (2004), made by A.V. Sanders, G.T. Gillies (ibid.).
N. A. Lockerbie is a member of the STEP (Satellite Test of the Equivalence Principle) Science Study Team, and an Associate
of the Institute for Gravitational Research at the University of Glasgow, Scotland, UK. 相似文献
189.
190.
The spectra of the intensity fluctuations of light scattered by large (erythrocytes of whole blood) and small (vesicles of surgical bile) particles in natural conditions were studied. It is shown that photon correlation spectroscopy can be used in analysis of variations in the size of biological particles in normal and pathological conditions and as an express method of noninvasive diagnostics of diseases. 相似文献