全文获取类型
收费全文 | 469712篇 |
免费 | 3147篇 |
国内免费 | 1217篇 |
专业分类
化学 | 223298篇 |
晶体学 | 7466篇 |
力学 | 25195篇 |
综合类 | 11篇 |
数学 | 66212篇 |
物理学 | 151894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 | 17247篇 |
2012年 | 16362篇 |
2011年 | 25245篇 |
2010年 | 17190篇 |
2009年 | 17405篇 |
2008年 | 22729篇 |
2007年 | 25423篇 |
2006年 | 13648篇 |
2005年 | 16724篇 |
2004年 | 13765篇 |
2003年 | 12875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 | 4932篇 |
1993年 | 4883篇 |
1992年 | 5290篇 |
1991年 | 5494篇 |
1990年 | 5207篇 |
1989年 | 5225篇 |
1988年 | 5193篇 |
1987年 | 5072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 15 毫秒
991.
992.
993.
Statistical Analysis of the Effect of Mineral Admixtures on the Strength of the Interfacial Transition Zone 总被引:1,自引:0,他引:1
Microscopic evidence indicates that the thickness of the interfacial transition zone (ITZ) between the aggregate and the cement paste is modified when mineral admixtures partially replace portland cement. Unfortunately, there is limited information on the significance of these microscopic modifications to the mechanical properties of the ITZ. This research reports experimental results on the shear and tensile strength of the ITZ as affected by the addition of the following mineral admixtures: silica fume, fly ash, and natural pozzolan. Statistical analysis was used to identify the significant parameters affecting the tensile and shear strength of the ITZ. Experimental results indicate that not only does the incorporation of silica fume and fly ash increase the strength of the ITZ, these mineral admixtures have a greater influence on the strength increase of the ITZ than in the strength increase of the cement paste. 相似文献
994.
995.
A. V. Koshelkin 《Journal of Experimental and Theoretical Physics》2003,96(4):653-657
On the basis of diagram formalism for two-particle Green functions, the bremsstrahlung of charged particles interacting in a dense medium is investigated. In the case of production of soft photons, exact expressions for two-particle Green functions corresponding to the process of particle bremsstrahlung in the substance are obtained. The Green functions found are fully determined by the set of closed irreducible diagrams. It is shown that, in the case of radiation in a sufficiently dense medium in a far long-wave region of the spectrum, the coherent multiple particle scattering results in an additional (as compared that reported earlier in [1–13]) suppression of the bremsstrahlung photon yield. 相似文献
996.
L. A. Falkovsky 《Journal of Experimental and Theoretical Physics》2003,96(2):335-339
The effect of free carriers on the dispersion and damping of coupled phonon-plasmon modes is considered in the long-wave approximation. The electron and phonon scattering rate, as well as Landau damping, is taken into account. 相似文献
997.
G. P. Klimov 《Applied Mathematics Letters》1991,4(6):95-97
Let F be a non-arithmetic distribution on the line
, and W be the class of bounded functions w without discontinuity of the second kind such that .In this paper, we show that the solution of the homogeneous renewal equation w = w F in the class W is a constant-function. 相似文献
998.
999.
This paper deals with a computational analysis of the influence of the pressing method and part geometry on the final density
distribution in the cold compaction process of ceramic alumina powders. The analysis is based on the explicit finite-element
model proposed and validated in a previous study. The mechanical behavior of the processing material is described using a
multisurface elastoplastic model, the modified Drucker-Prager/Cap model
Published in Prikladnaya Mekhanika, Vol. 43, No. 10, pp. 129–134, October 2007. 相似文献
1000.
V. Goryunov 《Proceedings of the Steklov Institute of Mathematics》2007,258(1):44-52
We establish a natural correspondence between the finite order automorphisms of the function singularities X
9 and the complex crystallographic groups. A complete list of the related objects is obtained.
To Vladimir Igorevich on the occasion of his 70th birthday 相似文献