全文获取类型
收费全文 | 369篇 |
免费 | 18篇 |
国内免费 | 2篇 |
专业分类
化学 | 219篇 |
晶体学 | 5篇 |
力学 | 15篇 |
数学 | 81篇 |
物理学 | 69篇 |
出版年
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 13篇 |
2020年 | 9篇 |
2019年 | 17篇 |
2018年 | 12篇 |
2017年 | 14篇 |
2016年 | 24篇 |
2015年 | 14篇 |
2014年 | 13篇 |
2013年 | 21篇 |
2012年 | 21篇 |
2011年 | 16篇 |
2010年 | 14篇 |
2009年 | 17篇 |
2008年 | 10篇 |
2007年 | 9篇 |
2006年 | 11篇 |
2005年 | 14篇 |
2004年 | 11篇 |
2003年 | 13篇 |
2002年 | 8篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 8篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1981年 | 11篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有389条查询结果,搜索用时 125 毫秒
41.
This work is concerned with the homogenization of solids reinforced by aligned parallel continuous fibers or weakened by aligned
parallel cylindrical pores and undergoing large deformations. By alternatively exploiting the nominal and material formulations
of the corresponding homogenization problem and by applying the implicit function theorem, it is shown that locally homogeneous
deformations can be produced in such inhomogeneous materials and form a differentiable manifold. For every macroscopic strain
associated to a locally homogeneous deformation field, the effective nominal or material stress–strain relation is exactly
determined and connections are also exactly established between the effective nominal and material elastic tangent moduli.
These results are microstructure-independent in the sense that they hold irrespectively of the transverse geometry and distribution
of the fibers or pores. A porous medium consisting of a compressible Mooney–Rivlin material with cylindrical pores is studied
in detail to illustrate the general results.
This work was the first time presented at the Euromech Colloqium 464 on “Fiber-reinforced Solids: Constitutive Laws and Instabilities”,
September 28–October 1, 2004, Cantabria, Spain. 相似文献
42.
Nguyen HT Tran HQ Nguyen TT Chau VM Bui KA Pham QL Nguyen MC Kim YH 《Chemical & pharmaceutical bulletin》2011,59(11):1417-1420
Ten oleanane-type saponins (1-10), including three new compounds, namely bifinosides A-C (1-3), were isolated from the roots of Panax bipinnatifidus SEEM. Their structures were elucidated on the basis of chemical and spectroscopic methods. 相似文献
43.
A mixed-valence uranium(IV,VI) germanate has been synthesized under high-temperature, high-pressure hydrothermal conditions. The structure contains discrete U(IV)O(6) octahedra and U(VI)O(6) tetragonal bipyramids, which are connected by three-membered single-ring Ge(3)O(9)(6-) anions to form a three-dimensional framework with 9-ring channels. The U 4f X-ray photoelectron spectroscopy spectrum was measured to identify the valence states of the uranium. 相似文献
44.
Quang A. Dang Manh T. Hoang Deccy Y. Trejos Jose C. Valverde 《Mathematical Methods in the Applied Sciences》2019,42(18):7517-7527
In this paper, we complete the study of the dynamics of a recognized continuous‐time model for the Babesiosis disease. The local and global asymptotic stability of the endemic state are established theoretically and experimentally. In addition, to restrain the disease in the original model when the endemic state exists, we propose and study the continuous model with feedback controls. The global stability of the boundary‐equilibrium point of this model is analyzed by means of rigorous mathematical methods. As an important consequence of this result, we propose a strategy to select feedback control variables in order to restrain the disease in the original model. This strategy allows us to make the disease vanish completely. In other words, the feedback controls are specially effective for restraining disease in the model. The validity of the established theoretical result is supported by a set of numerical simulations. 相似文献
45.
Numerical Algorithms - In this paper, we consider a fully third-order nonlinear boundary value problem that is of great interest of many researchers. First, we establish the existence and... 相似文献
46.
This work is a continuation of [7]. In that paper, a sufficient condition was given on a real analytic fmlction g defined near 0 in C so that the algebra generated by z2 and g2 is dense in the space of continuous functions on D for all disks D close enough to the origin in C. By using the same methods and some ideas taken from the first named author's thesis we deal with the case where g is only of class C1 near 0. 相似文献
47.
Dang Ngoc Quang Marc Stadler Jacques Fournier Toshihiro Hashimoto 《Tetrahedron》2006,62(26):6349-6354
Four azaphilones named cohaerins C-F, along with 4,5,4′,5′-tetrahydroxy-1,1′-binaphthyl were isolated from the methanolic extract of the stromata of Annulohypoxylon cohaerens (Ascomycetes, Xylariaceae). Cohaerins C-E constitute typical azaphilones, bearing a γ-lactone ring, while cohaerin F has an unprecedented carbon skeleton, lacking the lactone ring of the azaphilones and with an aliphatic side chain being attached directly to the azaphilone backbone by a C-C bond. Their structures were determined by 2D NMR, IR, UV, and CD spectroscopy. They showed moderate inhibitory activity of nitric oxide production in RAW cells, and strong and nonselective antimicrobial effects. 相似文献
48.
The aim of this note is to give a new proof and some improvements of Theorem 2.1 of Ref. 1, which plays an important role in deriving various optimality conditions. 相似文献
49.
50.
In this paper p-adic analogs of the Lichtenbaum Conjectures are proven for abelian number fields F and odd prime numbers p, which generalize Leopoldt's p-adic class number formula, and express special values of p-adic L-functions in terms of orders of K-groups and higher p-adic regulators. The approach uses syntomic regulator maps, which are the p-adic equivalent of the Beilinson regulator maps. They can be compared with étale regulators via the Fontaine-Messing map,
and computations of Bloch-Kato in the case that p is unramified in F lead to results about generalized Coates-Wiles homomorphisms and cyclotomic characters.
Oblatum 14-V-96 & 9-X-97 相似文献