全文获取类型
收费全文 | 535847篇 |
免费 | 4466篇 |
国内免费 | 1286篇 |
专业分类
化学 | 274431篇 |
晶体学 | 7690篇 |
力学 | 26138篇 |
综合类 | 17篇 |
数学 | 68902篇 |
物理学 | 164421篇 |
出版年
2021年 | 5117篇 |
2020年 | 5590篇 |
2019年 | 6359篇 |
2018年 | 8545篇 |
2017年 | 8716篇 |
2016年 | 11917篇 |
2015年 | 6435篇 |
2014年 | 10722篇 |
2013年 | 24006篇 |
2012年 | 18902篇 |
2011年 | 22418篇 |
2010年 | 16762篇 |
2009年 | 16553篇 |
2008年 | 21194篇 |
2007年 | 21013篇 |
2006年 | 19051篇 |
2005年 | 17050篇 |
2004年 | 15826篇 |
2003年 | 14222篇 |
2002年 | 14084篇 |
2001年 | 14788篇 |
2000年 | 11393篇 |
1999年 | 8809篇 |
1998年 | 7641篇 |
1997年 | 7515篇 |
1996年 | 6985篇 |
1995年 | 6296篇 |
1994年 | 6291篇 |
1993年 | 6045篇 |
1992年 | 6402篇 |
1991年 | 6894篇 |
1990年 | 6598篇 |
1989年 | 6512篇 |
1988年 | 6344篇 |
1987年 | 6154篇 |
1986年 | 5903篇 |
1985年 | 7446篇 |
1984年 | 7803篇 |
1983年 | 6549篇 |
1982年 | 6844篇 |
1981年 | 6355篇 |
1980年 | 6018篇 |
1979年 | 6517篇 |
1978年 | 6750篇 |
1977年 | 6641篇 |
1976年 | 6594篇 |
1975年 | 6311篇 |
1974年 | 6139篇 |
1973年 | 6428篇 |
1972年 | 4710篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
A. E. Mironov 《Functional Analysis and Its Applications》2005,39(3):240-243
We construct commuting rank 2 formally self-adjoint ordinary differential operators corresponding to a curve of genus 2. 相似文献
142.
143.
Glezer A.M. Blinova E.N. Pozdnyakov V.A. Shelyakov A.V. 《Journal of nanoparticle research》2003,5(5-6):551-560
Journal of Nanoparticle Research - It was shown that the thermoelastic martensite transformation B2 ? B19 inside nanoparticles surrounded by amorphous matrix in Ni–Ti–Cu alloys as... 相似文献
144.
A. V. Pukhlikov 《Computational Mathematics and Modeling》2004,15(3):223-256
The article develops the principles of optimal control theory for probability distributions on the configuration space of a controlled dynamical system. Necessary conditions of optimality are derived in the form of the Pontryagin principle for various classes of problems. Analytical representations in the space of distributions and observables are considered. Special modes are examined. The relationship between distribution control theory and nonlocal optimization problems is demonstrated. 相似文献
145.
A. I. Madunts 《Journal of Mathematical Sciences》2004,120(4):1609-1612
Some isomorphism criteria for Lubin–Tate formal groups over the ring of integers of a multidimensional local field are given. Bibliography: 4 titles. 相似文献
146.
The nonprimary subgroups of the symmetric group S
9 are investigated. Embedding properties of these subgroups are listed in a table. Properties such as abnormality, pronormality, paranormality, weak normality, etc. were checked with the help of a computer. Algorithms and codes of the first author were used for this purpose. The research leans upon the technique of Burnside marks, as well as upon pertinent information on the table of marks of S
9 from the computer algebra package GAP. The subgroups were investigated up to conjugacy; the total number of conjugacy classes of nonprimary subgroups of S
9 is 432. Some subgroups were additionally checked by other programs based on the double coset method. Bibliography: 24 titles. 相似文献
147.
E. A. Sopkina 《Journal of Mathematical Sciences》2004,124(1):4832-4836
An invariant of a closed set that is equal to the sum of roots is introduced. For a closed subset in a root system, we describe symmetric and special parts and its stabilizer in the Weyl group by means of the sum of roots. We determine associated bases with respect to which the closed set has the simplest form. All possible values of the root sum are found. Bibliography: 9 titles. 相似文献
148.
149.
Russian Journal of General Chemistry - 相似文献
150.
The kinetics of decay of a phase hologram in a semiconductor CdF2 crystal with bistable In centers is studied. Kinetic constants of the hologram decay are found, and the potential relief of the bistable center is plotted. The resolving power of the crystal is evaluated and recording of a transparency is demonstrated. 相似文献