全文获取类型
收费全文 | 5861篇 |
免费 | 165篇 |
国内免费 | 23篇 |
专业分类
化学 | 4040篇 |
晶体学 | 27篇 |
力学 | 98篇 |
数学 | 792篇 |
物理学 | 1092篇 |
出版年
2021年 | 47篇 |
2020年 | 50篇 |
2019年 | 64篇 |
2017年 | 30篇 |
2016年 | 108篇 |
2015年 | 117篇 |
2014年 | 110篇 |
2013年 | 215篇 |
2012年 | 197篇 |
2011年 | 210篇 |
2010年 | 129篇 |
2009年 | 137篇 |
2008年 | 185篇 |
2007年 | 206篇 |
2006年 | 212篇 |
2005年 | 206篇 |
2004年 | 197篇 |
2003年 | 159篇 |
2002年 | 194篇 |
2001年 | 121篇 |
2000年 | 100篇 |
1999年 | 95篇 |
1998年 | 95篇 |
1997年 | 81篇 |
1996年 | 91篇 |
1995年 | 79篇 |
1994年 | 87篇 |
1993年 | 89篇 |
1992年 | 92篇 |
1991年 | 98篇 |
1990年 | 85篇 |
1989年 | 86篇 |
1988年 | 106篇 |
1987年 | 118篇 |
1986年 | 82篇 |
1985年 | 129篇 |
1984年 | 125篇 |
1983年 | 83篇 |
1982年 | 113篇 |
1981年 | 115篇 |
1980年 | 102篇 |
1979年 | 118篇 |
1978年 | 90篇 |
1977年 | 91篇 |
1976年 | 83篇 |
1975年 | 74篇 |
1974年 | 88篇 |
1973年 | 62篇 |
1972年 | 31篇 |
1971年 | 49篇 |
排序方式: 共有6049条查询结果,搜索用时 285 毫秒
11.
For a graph G and a positive integer m, G(m) is the graph obtained from G by replacing every vertex by an independent set of size m and every edge by m2 edges joining all possible new pairs of ends. If G triangulates a surface, then it is easy to see from Euler's formula that G(m) can, in principle, triangulate a surface. For m prime and at least 7, it has previously been shown that in fact G(m) does triangulate a surface, and in fact does so as a “covering with folds” of the original triangulation. For m = 5, this would be a consequence of Tutte's 5‐Flow Conjecture. In this work, we investigate the case m = 2 and describe simple classes of triangulations G for which G(2) does have a triangulation that covers G “with folds,” as well as providing a simple infinite class of triangulations G of the sphere for which G(2) does not triangulate any surface. © 2003 Wiley Periodicals, Inc. J Graph Theory 43: 79–92, 2003 相似文献
12.
13.
The contributions to the coefficient functions of the quark and the mixed quark-gluon condensate to mesonic correlators are calculated for the first time to all orders in the quark masses, and to lowest order in the strong coupling constant. Existing results on the coefficient functions of the unit operator and the gluon condensate are reviewed. The proper factorization of short- and long-distance contributions in the operator product expansion is discussed in detail. It is found that to accomplish this task rigorously the operator product expansion has to be performed in terms ofnon-normal-ordered condensates. The resulting coefficient functions are improved with the help of the renormalization group. The scale invariant combination of dimension 5 operators, including mixing with the mass operator, which is needed for the renormalization group improvement, is calculated in the leading order.Supported by the German Bundesministerium für Forschung und Technologie, under the contract 06 TM 761 相似文献
14.
Manfred Sommer 《Constructive Approximation》2006,23(2):211-227
Hermite interpolation of 2n + k data by spline spaces of order k with n variable knots counting multiplicities is studied.
A characterization of the minimal spline spaces which admit a solution of the interpolation problem is obtained. A sufficient
condition on uniqueness of interpolating spline functions is given. 相似文献
15.
YoungJu Choie Olav K. Richter 《Proceedings of the American Mathematical Society》2007,135(8):2309-2315
We determine a class of functions spanned by theta series of higher degree. We give two applications: A simple proof of the inversion formula of such theta series and a classification of skew-holomorphic Jacobi forms.
16.
17.
Stefan Richter William T. Ross Carl Sundberg 《Proceedings of the American Mathematical Society》2004,132(8):2361-2365
In this paper, we refine a result of Nagel, Rudin, and Shapiro (1982) concerning the zeros of holomorphic functions on the unit disk with finite Dirichlet integral.
18.
19.
Arthur G. Maki John C. Grecu Brenda Winnewisser Manfred Winnewisser 《Journal of Molecular Spectroscopy》2003,222(2):198-212
High-resolution spectra of 15N12C12C15N and 14N13C13C14N have been measured and analyzed from 200 to 3600 cm−1. All the vibrational levels below 900 cm−1 have been observed and characterized. The Fermi resonance between ν2 and 2ν4 has been studied and the resonance constant has been determined for several cases. Several Σ− states have been directly observed for the first time for each isotopomer, the (0001111)0f, (0011111)0f, and (0002222)0f states. The pattern of the energy levels for clusters of l-type resonance coupled levels, such as 0001131,3, has been determined for cyanogen for the first time. Among other things this involved the determination of the vibrational l-type resonance constant, r45. Many of the power series constants, αi and xij, and higher order constants have been determined. 相似文献
20.
Ulf Pindur Ludwig Pfeuffer Manfred Eitel Martina Rogge Manfred Haber 《Monatshefte für Chemie / Chemical Monthly》1991,122(4):291-298
Summary Diels-Alder reactions of 2- and 3-vinylindoles with aryne, 1,4-benzo- and 1,4-naphtho-quinone lead to new six-ring annellated carbazoles. Molecular modeling studies predict that the compounds with coplanar framework are able to intercalate with the B-DNA. 相似文献