全文获取类型
收费全文 | 689670篇 |
免费 | 6522篇 |
国内免费 | 1766篇 |
专业分类
化学 | 354182篇 |
晶体学 | 10124篇 |
力学 | 34022篇 |
综合类 | 26篇 |
数学 | 90329篇 |
物理学 | 209275篇 |
出版年
2021年 | 5842篇 |
2020年 | 6519篇 |
2019年 | 7316篇 |
2018年 | 9772篇 |
2017年 | 9901篇 |
2016年 | 13930篇 |
2015年 | 7741篇 |
2014年 | 12756篇 |
2013年 | 30191篇 |
2012年 | 23131篇 |
2011年 | 27515篇 |
2010年 | 20323篇 |
2009年 | 20061篇 |
2008年 | 25980篇 |
2007年 | 25974篇 |
2006年 | 23897篇 |
2005年 | 21307篇 |
2004年 | 19732篇 |
2003年 | 17831篇 |
2002年 | 17724篇 |
2001年 | 18799篇 |
2000年 | 14669篇 |
1999年 | 11418篇 |
1998年 | 9890篇 |
1997年 | 9832篇 |
1996年 | 9215篇 |
1995年 | 8334篇 |
1994年 | 8469篇 |
1993年 | 8036篇 |
1992年 | 8629篇 |
1991年 | 9061篇 |
1990年 | 8717篇 |
1989年 | 8472篇 |
1988年 | 8402篇 |
1987年 | 8255篇 |
1986年 | 7848篇 |
1985年 | 10173篇 |
1984年 | 10718篇 |
1983年 | 9026篇 |
1982年 | 9370篇 |
1981年 | 8907篇 |
1980年 | 8592篇 |
1979年 | 8984篇 |
1978年 | 9471篇 |
1977年 | 9331篇 |
1976年 | 9338篇 |
1975年 | 8831篇 |
1974年 | 8730篇 |
1973年 | 9040篇 |
1972年 | 6564篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Theoretical and Mathematical Physics - We describe the procedure of dimensional reduction of massless fields in $$(d+1)$$ -dimensional Minkowski space to massive fields in $$d$$ dimensions in the... 相似文献
2.
Siberian Mathematical Journal - Let $ \{(A_{i},B_{i})\}_{i=1}^{m} $ be a set pair system. Füredi, Gyárfás, and Király called it $ 1 $ -cross intersecting if $... 相似文献
3.
Mathematical Notes - Subspaces of the space of analytic functions on a convex domain in the complex plane that are invariant with respect to the differentiation operator are studied. The problem of... 相似文献
4.
5.
Machado J. A. Tenreiro Rocha-Neves J. M. Azevedo Filipe Andrade J. P. 《Nonlinear dynamics》2021,106(2):1525-1555
Nonlinear Dynamics - Given a data-set of Ribonucleic acid (RNA) sequences we can infer the phylogenetics of the samples and tackle the information for scientific purposes. Based on current data and... 相似文献
6.
We show that near periodic rivet chains that connect two Kirchhoff plates and are modeled by point Sobolev transmission conditions, Rayleigh waves arise, propagate along the chains, and decay exponentially in the orthogonal direction. Under additional geometric conditions we discover the standing (periodic) waves that carry no energy.
相似文献7.
Numerical Algorithms - In this paper, the block generalized product-type bi-conjugate gradient (GPBi-CG) method for solving large, sparse nonsymmetric linear systems of equations with multiple... 相似文献
8.
Clemens G. Raab Georg Regensburger Jamal Hossein Poor 《Journal of Pure and Applied Algebra》2021,225(5):106564
A formal computation proving a new operator identity from known ones is, in principle, restricted by domains and codomains of linear operators involved, since not any two operators can be added or composed. Algebraically, identities can be modelled by noncommutative polynomials and such a formal computation proves that the polynomial corresponding to the new identity lies in the ideal generated by the polynomials corresponding to the known identities. In order to prove an operator identity, however, just proving membership of the polynomial in the ideal is not enough, since the ring of noncommutative polynomials ignores domains and codomains. We show that it suffices to additionally verify compatibility of this polynomial and of the generators of the ideal with the labelled quiver that encodes which polynomials can be realized as linear operators. Then, for every consistent representation of such a quiver in a linear category, there exists a computation in the category that proves the corresponding instance of the identity. Moreover, by assigning the same label to several edges of the quiver, the algebraic framework developed allows to model different versions of an operator by the same indeterminate in the noncommutative polynomials. 相似文献
9.
Kuz’mina L. G. Navasardyan M. A. Kalle P. Bezzubov S. I. 《Crystallography Reports》2021,66(3):420-423
Crystallography Reports - The crystal and molecular structures of Cl–C6H4–O–C16H33 (I) have been studied, and its differential scanning calorimetry (DSC) study is performed.... 相似文献
10.
Algebra and Logic - Unary functions definable in o-stable ordered groups of nonvaluational type are studied. Such functions are proved to be piecewise monotone and continuous. 相似文献