全文获取类型
收费全文 | 9578篇 |
免费 | 647篇 |
国内免费 | 1220篇 |
专业分类
化学 | 3394篇 |
晶体学 | 45篇 |
力学 | 186篇 |
综合类 | 146篇 |
数学 | 6240篇 |
物理学 | 1434篇 |
出版年
2024年 | 11篇 |
2023年 | 103篇 |
2022年 | 169篇 |
2021年 | 235篇 |
2020年 | 236篇 |
2019年 | 291篇 |
2018年 | 271篇 |
2017年 | 294篇 |
2016年 | 213篇 |
2015年 | 201篇 |
2014年 | 336篇 |
2013年 | 1026篇 |
2012年 | 312篇 |
2011年 | 433篇 |
2010年 | 377篇 |
2009年 | 519篇 |
2008年 | 583篇 |
2007年 | 751篇 |
2006年 | 571篇 |
2005年 | 524篇 |
2004年 | 458篇 |
2003年 | 491篇 |
2002年 | 432篇 |
2001年 | 354篇 |
2000年 | 341篇 |
1999年 | 324篇 |
1998年 | 304篇 |
1997年 | 266篇 |
1996年 | 193篇 |
1995年 | 112篇 |
1994年 | 129篇 |
1993年 | 81篇 |
1992年 | 79篇 |
1991年 | 58篇 |
1990年 | 43篇 |
1989年 | 43篇 |
1988年 | 41篇 |
1987年 | 42篇 |
1986年 | 24篇 |
1985年 | 41篇 |
1984年 | 22篇 |
1983年 | 15篇 |
1982年 | 19篇 |
1981年 | 19篇 |
1980年 | 10篇 |
1979年 | 7篇 |
1978年 | 11篇 |
1977年 | 12篇 |
1976年 | 4篇 |
1936年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
41.
The potential of an N-Troc-protected sialic acid donor, equipped with phenylsulfenyl functionality as a leaving group, has been explored. As a result, the entitled donor was proven to be highly reactive and to have broad applicability toward the synthesis of variant sialo-glycans, which have N-glycolyl, de-N-acetyl, 1,5-lactam and 8-O-sulfo sialic acid analogs. 相似文献
42.
Rie Natsui 《Acta Mathematica Hungarica》2005,108(4):299-318
Summary Let Fq be a finite field with q elements. We consider formal Laurent series of Fq -coefficients with their continued fraction expansions by Fq -polynomials. We prove some arithmetic properties for almost every formal Laurent series with respect to the Haar measure. We construct a group extension of the non-archimedean continued fraction transformation and show its ergodicity. Then we get some results as an application of the individual ergodic theorem. We also discuss the convergence rate for limit behaviors. 相似文献
43.
Krzysztof Pawaowski 《K-Theory》1998,13(1):41-55
The paper presents a procedure for constructing smooth actions of finite perfect groups on spheres with fixed point sets having certain prescribed properties (Theorem A); in particular, having any prescribed configuration of Chern and Pontryagin numbers (Corollary C). The main ingredients used are equivariant thickening and equivariant surgery. 相似文献
44.
该文利用算子半群的方法给出了取值于具有左不变度量的完备可分群的齐次Levy过程是复合Poisson过程的弱极限这一结论. 相似文献
45.
In this paper we show that the Boltzmann weights of the three-dimensional Baxter-Bazhanov model give representations of the braid group if some suitable spectral limits are taken. In the trigonometric case we classify all possible spectral limits which produce braid group representations. Furthermore, we prove that for some of them we get cyclotomic invariants of links and for others we obtain tangle invariants generalizing the cyclotomic ones. 相似文献
46.
Ignacio Bajo 《Geometriae Dedicata》1997,66(3):281-291
Lie groups with bi-invariant semi-Riemannian metrics are considered. We study the decomposition of the algebra of prederivations of a direct sum of Lie algebras and derive some results on the isotropy group of a bi-invariant product Lie group. We also give necessary and sufficient conditions to ensure that all isometries of a complex Lie group, endowed with a bi-invariant Norden metric, are holomorphic. 相似文献
47.
Summary It is shown that the outer automorphism group of a Coxeter groupW of finite rank is finite if the Coxeter graph contains no infinite bonds. A key step in the proof is to show that if the
group is irreducible andΠ
1 andΠ
2 any two bases of the root system ofW, thenΠ
2 = ±ωΠ
1 for some ω εW. The proof of this latter fact employs some properties of the dominance order on the root system introduced by Brink and
Howlett.
This article was processed by the author using the Springer-Verlag TEX PJour1g macro package 1991. 相似文献
48.
49.
本文用变换群理论对运动水平平板混合对流边界层流动的动量、能量和浓度扩散方程进行了分析,得到了与X4/(7-5n)成正比的壁面温度分布和浓度分布,同时壁面运动速度正比于X(3-n)/(7-5n)时存在相似性解.导出了相似性解方程,用四阶Runge-Kutta方法进行了计算,给出了Pr=0.72 和Sc,K1,K2,K3参数下的速度、温度和浓度分布,得出了各参数对流场、温度场的影响。 相似文献
50.
S. Moss de Oliveira P. M. C. de Oliveira F. C. de Sá Barreto 《Journal of statistical physics》1995,78(5-6):1619-1627
Using the finite-size scaling renormalization group, we obtain the two-dimensional flow diagram of the Blume-Capel model forS=1 andS=3/2. In the first case our results are similar to those of mean-field theory, which predicts the existence of first- and second-order transitions with a tricritical point. In the second case, however, our results are different. While we obtain in theS=1 case a phase diagram presenting a multicritical point, the mean-field approach predicts only a second-order transition and a critical endpoint. 相似文献