全文获取类型
收费全文 | 8595篇 |
免费 | 219篇 |
国内免费 | 7篇 |
专业分类
化学 | 5191篇 |
晶体学 | 143篇 |
力学 | 164篇 |
数学 | 1215篇 |
物理学 | 2108篇 |
出版年
2022年 | 38篇 |
2021年 | 246篇 |
2020年 | 137篇 |
2019年 | 166篇 |
2018年 | 158篇 |
2017年 | 162篇 |
2016年 | 288篇 |
2015年 | 223篇 |
2014年 | 305篇 |
2013年 | 701篇 |
2012年 | 467篇 |
2011年 | 526篇 |
2010年 | 383篇 |
2009年 | 356篇 |
2008年 | 427篇 |
2007年 | 423篇 |
2006年 | 347篇 |
2005年 | 312篇 |
2004年 | 279篇 |
2003年 | 259篇 |
2002年 | 207篇 |
2001年 | 148篇 |
2000年 | 138篇 |
1999年 | 103篇 |
1998年 | 107篇 |
1997年 | 79篇 |
1996年 | 81篇 |
1995年 | 100篇 |
1994年 | 60篇 |
1993年 | 48篇 |
1992年 | 74篇 |
1991年 | 47篇 |
1990年 | 65篇 |
1989年 | 60篇 |
1988年 | 71篇 |
1987年 | 58篇 |
1986年 | 65篇 |
1985年 | 97篇 |
1984年 | 109篇 |
1983年 | 67篇 |
1982年 | 63篇 |
1981年 | 70篇 |
1980年 | 84篇 |
1979年 | 59篇 |
1978年 | 63篇 |
1977年 | 66篇 |
1976年 | 66篇 |
1975年 | 54篇 |
1974年 | 49篇 |
1973年 | 44篇 |
排序方式: 共有8821条查询结果,搜索用时 15 毫秒
61.
62.
Zbigniew Peradzyński Bogdan Kazmierczak 《Archive of Applied Mechanics (Ingenieur Archiv)》2005,74(11-12):827-833
The influence of mechano-chemical coupling on calcium concentration waves is considered. The propagation of calcium waves is described by a reaction–diffusion equation with the reaction term dependent on the mechanical stress responsible for the release of calcium. Similarly the balance of mechanical forces is influenced by the calcium concentration through the so-called traction force. 相似文献
63.
Dealing with infinite iterated function systems we introduce and develop the ergodic theory of Hölder systems of functions similarly as in [HU] and [HMU]. In the context of conformal infinite iterated function systems we prove the volume lemma for the Hausdorff dimension of the projection onto the limit set of a shift invariant measure. This can be considered as a Billingsley type result. Our cenral goal is to demonstrate the appearance of the "singularity-absolute continuity" dichotomy for equilibrium states of Hölder systems of functions which has been observed in [PUZ,I] and [PUZ,II] (see also [DU1] and [DU2]) in the setting of rational functions of the Riemann sphere. 相似文献
64.
65.
X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) have been used to investigate the effect of reactive ion etching (RIE) on poly(methylhydrogensiloxane-co-dimethylsiloxane) surface in fluorine-based plasmas. Polysiloxane layers supported on the standard silicon wafers were etched using SF6 + O2 or CF4 + O2 plasmas. SEM studies show that the polysiloxane morphology depends on plasma chemical composition strongly. Presence of a columnar layer likely covered with a fluorine rich compound was found on the elastomer surface after the CF4 + O2 plasma exposure. After the SF6 + O2 or CF4 + O2 plasma treatment the polysiloxane surface enriches with fluorine or with fluorine and aluminum, respectively. Different morphologies and surface chemical compositions of the silicone elastomer etched in both plasmas indicate different etching mechanisms. 相似文献
66.
We describe phenomena occurring just before a saddle-node bifurcation for one-parameter families of interval maps. In particular, as a parameter approaches the bifurcation value, attracting periodic orbits of periodsk, k+1,k+2,k+3,... can appear. We make a detailed study of a family of cusp-shaped maps, where this phenomenon occurs in a pure form. 相似文献
67.
Dr. A. Kaczyński Dr. S. J. Matysiak 《Archive of Applied Mechanics (Ingenieur Archiv)》1988,58(2):137-147
Summary This paper deals with the two-dimensional static punch problems in the presence of friction for a periodically layered half-space. Within the framework of the homogenized model of linear elasticity with microlocal parameters [8–11] the exact solutions of the considered problems are obtained. The case of the indentation of the composite body by a rigid rectangular punch has been discussed in detail.
Ebene Kontaktprobleme für ein periodisches elastisches Zweischichten-Komposit
Übersicht In dieser Arbeit wird das zweidimensionale statische Stempelproblem mit Reibung für einen periodisch geschichteten Halbraum betrachtet. Im Rahmen eines Homogenisierungsmodells der linearen Elastizitätstheorie mit mikropolaren Parametern werden die exakten Lösungen der betrachteten Probleme gewonnen. Im Detail wird das Eindringen eines rechteckigen starren Stempels behandelt.相似文献
68.
Margaret C. Etter Zofia Urbańczyk-Lipkowska Touradj M. Ameli Thomas W. Panunto 《Journal of chemical crystallography》1988,18(5):491-507
The crystal structures, solid-state infrared patterns, and thermal properties of two polymorphs of 4-nitrosalicylanilide are presented. In both polymorphs, intramolecular hydrogen bonds are found between the phenol oxygen and the amide proton, and intermolecular hydrogen bonds are found between the amide carbonyl oxygen and the phenol proton. These hydrogen bond patterns are compared to those found in other known salicylamide derivatives and an analysis is given of the factors contributing to preferences for intra- or intermolecular hydrogen bonds in these structures. Crystal data: polymorph, orthorhombic,Pbca,a=11.003(4),b=27.959(7),c=7.622(5) Å,Z=4,V=2345(3) Å3, andR=0.038 (1351 reflections); polymorph, monoclinic,P21/a,a=28.36(1),b=11.64(1),c=7.293(8) Å,=90.68(6)°,Z=8,V=2408 Å3, andR=0.043 (2425 reflections). 相似文献
69.
Creep resistance investigations of the Al-40 wt % Zn alloy at room temperature have been performed and revealed some creep compliance. Additions of Cu and Si decrease considerably the preliminary creep compliance in the alloy which then turn to be dimensionally stable and resistant to creep. Tensile test investigations performed at different deformation rates have not revealed the existance of the superplastic deformation mechanism.Presented at the 4th International Symposium on Plasticity of Metals and Alloys, September 711, 1987, Srni, Czechoslovakia. 相似文献
70.
Robert J. Budzyński Sławomir Klimek Paweł Sadowski 《Communications in Mathematical Physics》1989,120(3):481-499
Motivated by the operator formulation of conformal field theory on Riemann surfaces, we study the properties of the infinite dimensional group of local biholomorphic transformations (conformal reparametrizations) of 1 and develop elements of its representation theory. 相似文献