全文获取类型
收费全文 | 3993篇 |
免费 | 214篇 |
国内免费 | 139篇 |
专业分类
化学 | 85篇 |
晶体学 | 1篇 |
力学 | 12篇 |
综合类 | 33篇 |
数学 | 4018篇 |
物理学 | 197篇 |
出版年
2024年 | 12篇 |
2023年 | 62篇 |
2022年 | 81篇 |
2021年 | 74篇 |
2020年 | 118篇 |
2019年 | 116篇 |
2018年 | 126篇 |
2017年 | 115篇 |
2016年 | 82篇 |
2015年 | 68篇 |
2014年 | 140篇 |
2013年 | 302篇 |
2012年 | 174篇 |
2011年 | 199篇 |
2010年 | 199篇 |
2009年 | 363篇 |
2008年 | 344篇 |
2007年 | 250篇 |
2006年 | 236篇 |
2005年 | 156篇 |
2004年 | 134篇 |
2003年 | 126篇 |
2002年 | 108篇 |
2001年 | 98篇 |
2000年 | 81篇 |
1999年 | 86篇 |
1998年 | 76篇 |
1997年 | 71篇 |
1996年 | 50篇 |
1995年 | 33篇 |
1994年 | 32篇 |
1993年 | 27篇 |
1992年 | 24篇 |
1991年 | 19篇 |
1990年 | 19篇 |
1989年 | 15篇 |
1988年 | 14篇 |
1987年 | 4篇 |
1986年 | 7篇 |
1985年 | 22篇 |
1984年 | 16篇 |
1983年 | 10篇 |
1982年 | 14篇 |
1981年 | 8篇 |
1980年 | 15篇 |
1979年 | 4篇 |
1978年 | 9篇 |
1977年 | 4篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有4346条查询结果,搜索用时 31 毫秒
41.
Eric Gifford Mark Johnson Chun-che Tsai 《Journal of computer-aided molecular design》1991,5(4):303-322
Summary The metabolic pathways of medazepam, oxazepam, and diazepam were modeled using graph-theoretic transforms which are incorporable into computer-assisted metabolic analysis programs. The information, represented in the form of a graph-theoretic transform kit, which was obtained from these pathways was then used to predict the metabolites of other benzodiazepine compounds. The transform kits gave statistically significant predictions with respect to a statistical method for evaluating the performance of the transform kits. 相似文献
42.
Jaroslav Neetil 《Journal of Graph Theory》2002,39(2):108-110
A graph G is called rigid if the identical mapping V(G)→V(G) is the only homomorphism G→G. In this note we give a simple construction of a rigid oriented graph on every set. © 2002 John Wiley & Sons, Inc. J Graph Theory 39: 108–110, 2002 相似文献
43.
In the core of the seminal Graph Minor Theory of Robertson and Seymour lies a powerful theorem capturing the ``rough' structure
of graphs excluding a fixed minor. This result was used to prove Wagner's Conjecture that finite graphs are well-quasi-ordered
under the graph minor relation. Recently, a number of beautiful results that use this structural result have appeared. Some
of these along with some other recent advances on graph minors are surveyed.
Research partly supported by Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research, Grant number
16740044, by Sumitomo Foundation, by C & C Foundation and by Inoue Research Award for Young Scientists
Supported in part by the Research Grant P1–0297 and by the CRC program
On leave from: IMFM & FMF, Department of Mathematics, University of Ljubljana, Ljubljana, Slovenia 相似文献
44.
We provide some inequalities and integral inequalities connected to the Jensen-Hadamard inequalities for convex functions.
In particular, we give some refinements to these inequalities. Some natural applications and further extensions are given.
Sunto Forniamo alcune diseguaglianze e diseguaglianze integrali connesse alle dise-gueglianze di Jensen-Hadamard per funzioni convesse. In particolare, diamo qualche miglioramento di queste diseguaglianze. Alcune applicazioni naturali ed ulteriori estensioni sono date.相似文献
45.
王军秀 《纯粹数学与应用数学》2007,23(3):406-408
利用欧拉公式研究了Gdk图的平面性,获得了一个重要定理,并由此得到了关于平面图色数的一个结论. 相似文献
46.
K. C. Kiwiel 《Journal of Optimization Theory and Applications》2007,134(3):549-554
We give a linear time algorithm for the continuous quadratic knapsack problem which is simpler than existing methods and competitive
in practice. Encouraging computational results are presented for large-scale problems.
The author thanks the Associate Editor and an anonymous referee for their helpful comments. 相似文献
47.
Q.J. Zhu 《Journal of Mathematical Analysis and Applications》2007,326(1):708-720
Investment systems are studied using a framework that emphasize their profiles (the cumulative probability distribution on all the possible percentage gains of trades) and their log return functions (the expected average return per trade in logarithmic scale as a function of the investment size in terms of the percentage of the available capital). The efficiency index for an investment system, defined as the maximum of the log return function, is proposed as a measure to compare investment systems for their intrinsic merit. This efficiency index can be viewed as a generalization of Shannon's information rate for a communication channel. Applications are illustrated. 相似文献
48.
Jesús de la Cal Javier Cárcamo 《Journal of Mathematical Analysis and Applications》2007,334(2):1106-1115
As a consequence of Jensen's inequality, centered operators of probabilistic type (also called Bernstein-type operators) approximate convex functions from above. Starting from this fact, we consider several pairs of classical operators and determine, in each case, which one is better to approximate convex functions. In almost all the discussed examples, the conclusion follows from a simple argument concerning composition of operators. However, when comparing Szász-Mirakyan operators with Bernstein operators over the positive semi-axis, the result is derived from the convex ordering of the involved probability distributions. Analogous results for non-centered operators are also considered. 相似文献
49.
50.
Alistair Savage 《Algebras and Representation Theory》2006,9(2):161-199
For irreducible integrable highest weight modules of the finite and affine Lie algebras of type A and D, we define an isomorphism between the geometric realization of the crystal graphs in terms of irreducible components of Nakajima
quiver varieties and the combinatorial realizations in terms of Young tableaux and Young walls. For type An(1), we extend the Young wall construction to arbitrary level, describing a combinatorial realization of the crystals in terms
of new objects which we call Young pyramids.
Presented by P. Littleman
Mathematics Subject Classifications (2000) Primary 16G10, 17B37.
Alistair Savage: This research was supported in part by the Natural Sciences and Engineering Research Council (NSERC) of Canada
and was partially conducted by the author for the Clay Mathematics Institute. 相似文献