全文获取类型
收费全文 | 184244篇 |
免费 | 857篇 |
国内免费 | 288篇 |
专业分类
化学 | 92990篇 |
晶体学 | 2699篇 |
力学 | 9488篇 |
综合类 | 7篇 |
数学 | 21598篇 |
物理学 | 58607篇 |
出版年
2020年 | 1900篇 |
2019年 | 2332篇 |
2018年 | 3417篇 |
2017年 | 3545篇 |
2016年 | 4221篇 |
2015年 | 1920篇 |
2014年 | 3657篇 |
2013年 | 7239篇 |
2012年 | 5724篇 |
2011年 | 6844篇 |
2010年 | 5630篇 |
2009年 | 5732篇 |
2008年 | 6589篇 |
2007年 | 6609篇 |
2006年 | 5893篇 |
2005年 | 5240篇 |
2004年 | 5021篇 |
2003年 | 4569篇 |
2002年 | 4718篇 |
2001年 | 5057篇 |
2000年 | 3738篇 |
1999年 | 2885篇 |
1998年 | 2661篇 |
1997年 | 2506篇 |
1996年 | 2350篇 |
1995年 | 2118篇 |
1994年 | 2060篇 |
1993年 | 2102篇 |
1992年 | 2128篇 |
1991年 | 2411篇 |
1990年 | 2361篇 |
1989年 | 2428篇 |
1988年 | 2309篇 |
1987年 | 2336篇 |
1986年 | 2171篇 |
1985年 | 2728篇 |
1984年 | 2753篇 |
1983年 | 2357篇 |
1982年 | 2437篇 |
1981年 | 2328篇 |
1980年 | 2132篇 |
1979年 | 2457篇 |
1978年 | 2604篇 |
1977年 | 2687篇 |
1976年 | 2773篇 |
1975年 | 2595篇 |
1974年 | 2519篇 |
1973年 | 2673篇 |
1972年 | 2173篇 |
1971年 | 1994篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
73.
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
74.
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
75.
76.
77.
S. E. Bogushevich V. N. Makatun A. K. Potapovich I. I. Ugolev 《Journal of Applied Spectroscopy》1991,55(4):1016-1020
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 4, pp. 613–618, October, 1991. 相似文献
78.
S. I. Okrut 《Journal of Mathematical Sciences》1991,53(5):526-532
We consider strongly parabolic, Hilbert submanifolds in Riemannian Hilbert manifolds. We prove that their properties are analogous to the known properties in the finite-dimensional case. The main geometric result consists of Theorem 3: a complete, Riemannian, Hilbert submanifold of nonpositive extrinsic curvature and finite codimension in a Hilbert sphere is a great sphere.Translated from Ukrainskii Geometricheskii Sbornik, No. 33, pp. 91–100, 1990.The author expresses his thanks to Professor A. A. Borisenko for posing the problem and guiding the work. 相似文献
79.
S. A. Logvinenko I. N. Timoshina Yu. V. Moseev 《Journal of Mathematical Sciences》1991,57(5):3361-3366
Modifications are introduced into the large-particle method to make it possible to use the method in arbitrary nonrectangular computing nets in the study of the flow of an ideal compressible gas over mobile thin permeable membranes. A problem in the aeroelasticity of a parachute is stated. An example is given of the solution of a problem in the stationary formulation for an axially symmetric parachute in the wake of a cylindrical leading body for supersonic flow.Translated fromDinamicheskie Sistemy, No. 6, 1987, pp. 16–22 相似文献
80.