全文获取类型
收费全文 | 636篇 |
免费 | 4篇 |
国内免费 | 5篇 |
专业分类
化学 | 314篇 |
晶体学 | 1篇 |
力学 | 15篇 |
数学 | 133篇 |
物理学 | 182篇 |
出版年
2019年 | 4篇 |
2014年 | 5篇 |
2013年 | 13篇 |
2012年 | 12篇 |
2011年 | 20篇 |
2010年 | 9篇 |
2009年 | 7篇 |
2008年 | 18篇 |
2007年 | 26篇 |
2006年 | 16篇 |
2005年 | 23篇 |
2004年 | 36篇 |
2003年 | 19篇 |
2002年 | 20篇 |
2001年 | 18篇 |
2000年 | 18篇 |
1999年 | 12篇 |
1998年 | 7篇 |
1997年 | 12篇 |
1996年 | 13篇 |
1995年 | 15篇 |
1994年 | 14篇 |
1993年 | 18篇 |
1992年 | 15篇 |
1991年 | 9篇 |
1990年 | 14篇 |
1989年 | 5篇 |
1988年 | 17篇 |
1987年 | 9篇 |
1986年 | 7篇 |
1985年 | 18篇 |
1984年 | 17篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 19篇 |
1980年 | 12篇 |
1979年 | 12篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 11篇 |
1974年 | 8篇 |
1973年 | 16篇 |
1972年 | 6篇 |
1971年 | 4篇 |
1970年 | 7篇 |
1969年 | 6篇 |
1968年 | 6篇 |
1967年 | 9篇 |
1966年 | 5篇 |
排序方式: 共有645条查询结果,搜索用时 0 毫秒
81.
We prove Grünbaum's conjecture that every arrangement of eight pseudolines in the projective plane is stretchable, i.e., determines a cell complex isomorphic to one determined by an arrangement of lines. The proof uses our previous results on ordered duality in the projective plane and on periodic sequences of permutations of [1,n] associated to arrangements of n lines in the euclidean plane. 相似文献
82.
The mechanics of a circular, spot weld between two identical elastic plates is studied. A method of solution similar to that used by the authors in a paper concerned with the influence of an elastic layer on the tangential compliance of bodies in contact is used. In the present analysis the relation between tangential load and deflection is lost due to the nature of the problem; hence, physical quantities are determined in terms of the total tangential load applied in the weld region. 相似文献
83.
Gerald S. Goodman 《Milan Journal of Mathematics》1977,47(1):123-134
By use of a new result concerning the validity of the chain rule for the derivative of a composite function, the author succeeds in extending the classical change of variable formula for Lebesgue and Denjoy/Perron integrals to the case in which the change is effected by continuousN-functions of unbounded variation. A novelty of the resulting formula is that the integration is only carried out over the set where theN-function is differentiable, and that set may fail to have full measure, as an example shows. 相似文献
84.
I. Goodman 《European Polymer Journal》1984,20(6):549-557
The chain structures of copolyesteramides formed by anionic ring-opening copolymerisation of ε-caprolactam with ε-caprolactone have been investigated. The copolymers are shown to possess random multiblock structures with chains composed of O(CH2)5CO[NH(CH2)5CO]n groups (having relatively small values of n) intercalated with sequences of O(CH2)5CO groups. The distributions of structural units in the chains are significantly affected by reaction time and by the method of introducing lactone into the copolymerising system. A mechanism is proposed to explain the formation of the multiblock structures. The nature of an additional absorbance in the NH-stretching region of the i.r. spectra of the copolyesteramides has been investigated with the aid of model compounds and attributed to hydrogen-bonding between amide and ester groups in the amorphous regions of the copolymers. This bonding may be the cause of the anomalous mechanical properties found at high ester contents. 相似文献
85.
86.
87.
We associate, to any ordered configuration of n points or ordered arrangement of n lines in the plane, a periodic sequence of permutations of [1, n] in a way which reflects the order and convexity properties of the configuration or arrangement, and prove that a sequence of permutations of [1, n] is associated to some configuration of points if and only if it is associated to some arrangement of lines. We show that this theorem generalizes the standard duality principle for the projective plane, and we use it to derive duals of several well-known theorems about arrangements, including a version of Helly's theorem for convex polygons. 相似文献
88.
In this paper some new results on analytic domination of operators and on integrability of Lie algebras of operators are proved and then our methods are applied to the study of Lie algebras of unbounded derivations in algebras. 相似文献
89.
90.