全文获取类型
收费全文 | 10896篇 |
免费 | 724篇 |
国内免费 | 1309篇 |
专业分类
化学 | 3424篇 |
晶体学 | 48篇 |
力学 | 635篇 |
综合类 | 152篇 |
数学 | 7038篇 |
物理学 | 1632篇 |
出版年
2024年 | 13篇 |
2023年 | 125篇 |
2022年 | 196篇 |
2021年 | 256篇 |
2020年 | 278篇 |
2019年 | 327篇 |
2018年 | 309篇 |
2017年 | 322篇 |
2016年 | 260篇 |
2015年 | 232篇 |
2014年 | 419篇 |
2013年 | 1190篇 |
2012年 | 370篇 |
2011年 | 502篇 |
2010年 | 431篇 |
2009年 | 610篇 |
2008年 | 658篇 |
2007年 | 847篇 |
2006年 | 655篇 |
2005年 | 589篇 |
2004年 | 506篇 |
2003年 | 537篇 |
2002年 | 484篇 |
2001年 | 376篇 |
2000年 | 369篇 |
1999年 | 354篇 |
1998年 | 329篇 |
1997年 | 289篇 |
1996年 | 215篇 |
1995年 | 121篇 |
1994年 | 138篇 |
1993年 | 92篇 |
1992年 | 83篇 |
1991年 | 62篇 |
1990年 | 43篇 |
1989年 | 43篇 |
1988年 | 42篇 |
1987年 | 42篇 |
1986年 | 27篇 |
1985年 | 43篇 |
1984年 | 25篇 |
1983年 | 15篇 |
1982年 | 20篇 |
1981年 | 21篇 |
1980年 | 11篇 |
1979年 | 9篇 |
1978年 | 11篇 |
1977年 | 13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 15 毫秒
181.
A. Salam 《Numerical Algorithms》1996,11(1):327-337
The vector -algorithm is obtained from the scalar -algorithm by taking the pseudo-inverse of a vector instead of the inverse of a scalar. Thus the vector -algorithm is known only through its rules contrarily to the scalar -algorithm and some other extrapolation algorithms.The aim of this paper is to provide an algebraic approach to the vector -algorithm. 相似文献
182.
Peter J. Cameron 《Designs, Codes and Cryptography》1996,8(3):109-133
The main theme of this article is that counting orbits of an infinite permutation group on finite subsets or tuples is very closely related to combinatorial enumeration; this point of view ties together various disparate stories. Among these are reconstruction problems, the relation between connected and arbitrary graphs, the enumeration of N-free posets, and some of the combinatorics of Stirling numbers.Dedicated to Hanfried Lenz on the occasion of his 80th birthday. 相似文献
183.
Haruto Ohta 《Proceedings of the American Mathematical Society》1996,124(3):961-967
Answering a question of Eklof-Mekler (Almost free modules, set-theoretic methods, North-Holland, Amsterdam, 1990), we prove: (1) If there exists a non-reflecting stationary set of consisting of ordinals of cofinality for each , then there exist abelian groups such that and for each . (2) There exist abelian groups such that for each and for each . The groups are the groups of -valued continuous functions on a topological space and their dual groups.
184.
Yu Chen 《Transactions of the American Mathematical Society》1996,348(9):3733-3743
We demonstrate a one to one correspondence between the irreducible projective representations of an affine Kac-Moody group and those of the related loop group, which leads to the results that every non-trivial representation of an affine Kac-Moody group must have its degree greater than or equal to the rank of the group and that the equivalence appears if and only if the group is of type for some . Moreover the characteristics of the base fields for the non-trivial representations are found being always zero.
185.
Algebraic surfaces with log canonical singularities and the fundamental groups of their smooth parts
D.-Q. Zhang 《Transactions of the American Mathematical Society》1996,348(10):4175-4184
Let be a log surface with at worst log canonical singularities and reduced boundary such that is nef and big. We shall prove that either has finite fundamental group or is affine-ruled. Moreover, and the structure of are determined in some sense when .
186.
John Kalliongis Darryl McCullough 《Transactions of the American Mathematical Society》1996,348(5):1739-1755
The observation that the quotient orbifold of an orientation- reversing involution on a 3-dimensional handlebody has the structure of a compression body leads to a strong classification theorem, and general structure theorems. The structure theorems decompose the action along invariant discs into actions on handlebodies which preserve the -fibers of some -bundle structure. As applications, various results of R. Nelson are proved without restrictive hypotheses.
187.
Zhao Xuezhi 《数学学报(英文版)》1996,12(1):71-76
Letf:XX be a selfmap of a compact connected polyhedron, andA a nonempty closed subset ofX. In this paper, we shall deal with the question whether or not there is a mapg:XX homotopic tof such that the fixed point set Fixg ofg equalsA. We introduce a necessary condition for the existence of such a mapg. It is shown that this condition is easy to check, and hence some sufficient conditions are obtained.Partially supported by the Natural Science Foundation of Liaoning University. 相似文献
188.
The reactions of three aromatic hydrocarbons, benzene, toluene, and styrene, with oxygen in a radiofrequency (r) plasma were investigated. Benzene was oxidized to yield phenol as a single volatile organic product. Similarly, toluene gave the ring oxidation products, cresols, as well as considerable amounts of methyl oxidation products, consisting mainly of benzaldehyde and benzyl alcohol. In contrast, the oxidation of styrene took place predominantly on the olefinic double bond to produce styrene oxide On basis of the products and effects of reaction variables, r power and flow rates of hydrocarbons and oxygen, on the reaction rate, the oxidation mechanism was discussed, particularly focusing on the intermediate species responsible for the formation of major products. 相似文献
189.
Janusz Grabowski 《Annals of Global Analysis and Geometry》1993,11(3):213-220
It is proved that for infinite dimensional Lie groups in the sense of the differential calculus of Frölicher and Kriegl the derivative of the exponential mappings is given by the formula d(exp)(X)Y=dexp(X)(e)
0
1
Adexp(–tX)
Y dt, where stands for the left translation ande is the neutral element.This work was supported by the Alexander von Humboldt-Stiftung. 相似文献
190.
Jong-Shi Pang 《Mathematical Programming》1993,58(1-3):149-160
This paper is concerned with two well-known families of iterative methods for solving the linear and nonlinear complementarity problems. For the linear complementarity problem, we consider the class of matrix splitting methods and establish, under a finiteness assumption on the number of solutions, a necessary and sufficient condition for the convergence of the sequence of iterates produced. A rate of convergence result for this class of methods is also derived under a stability assumption on the limit solution. For the nonlinear complementarity problem, we establish the convergence of the Newton method under the assumption of a pseudo-regular solution which generalizes Robinson's concept of a strongly regular solution. In both instances, the convergence proofs rely on a common sensitivity result of the linear complementarity problem under perturbation.This work was based on research supported by the National Science Foundation under grant ECS-8717968. 相似文献