全文获取类型
收费全文 | 245篇 |
免费 | 5篇 |
学科分类
数理化 | 250篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 18篇 |
2012年 | 11篇 |
2011年 | 11篇 |
2010年 | 7篇 |
2009年 | 6篇 |
2008年 | 15篇 |
2007年 | 14篇 |
2006年 | 12篇 |
2005年 | 10篇 |
2004年 | 12篇 |
2003年 | 12篇 |
2002年 | 13篇 |
2001年 | 13篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 10篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 10篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 6篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1961年 | 1篇 |
1955年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有250条查询结果,搜索用时 0 毫秒
1.
2.
Gudrun Thter 《Mathematical Methods in the Applied Sciences》2002,25(10):875-894
The Neumann problem is crucial in mathematical physics. Nevertheless, as far as cylindrical domains are concerned there is still the open question how to construct solutions to data in usual Sobolev spaces since the standard Kondratiev theory does not apply. In this paper that unsatisfactory gap is filled and moreover, data with polynomial asymptotic behaviour are considered. As interesting special case we find solutions with bounded Dirichlet integral. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
3.
4.
Matthew M. Malwitz Paul D. Butler Lionel Porcar Drew P. Angelette Gudrun Schmidt 《Journal of polymer science. Part A, Polymer chemistry》2004,42(17):3102-3112
The influence of shear on viscoelastic solutions of poly(ethylene oxide) (PEO) and clay [montmorillonite, i.e., Cloisite NA+ (CNA)] was investigated with rheology and small-angle neutron scattering (SANS). The steady-state viscosity and SANS were used to measure the shear-induced orientation and relaxation of the polymer and clay platelets. Anisotropic scattering patterns developed at much lower shear rates than in pure clay solutions. The scattering anisotropy saturated at low shear rates, and the CNA clay platelets aligned with the flow, with the surface normal parallel to the gradient direction. The cessation of shear led to partial and slow randomization of the CNA platelets, whereas extremely fast relaxation was observed for laponite (LRD) platelets. These PEO–CNA networklike solutions were compared with previously reported PEO–LRD networks, and the differences and similarities, with respect to the shear orientation, relaxation, and polymer–clay interactions, were examined. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3102–3112, 2004 相似文献
5.
Doz. Dr. Karl Gewald Gudrun Heinhold 《Monatshefte für Chemie / Chemical Monthly》1976,107(6):1413-1421
The alkylation of arylaminomethylenecyanamides1 or cyano-imidothiocarbamates2 with -halogen carbonyl compounds followed by base catalysed cyclization yields substituted 4-amino-imidazoles4. Imidazo[4,5-d]pyrimidones5, 6 and imidazo[4,5-b]pyridines7 can be obtained from4. 相似文献
6.
K3MnH5, the First Salt-like Manganese Hydride K3MnH5 and K3MnD5 were synthesized by the reaction of potassium hydride (deuteride) with manganese powder under a hydrogen pressure above 3000 bar at 875 K. X-ray investigations on powdered samples and elastic neutron diffraction experiments on the deuterated compound at the time-of-flight spectrometer LAD in the temperature range 5–600 K led to the complete structure determination. The atomic arrangement is isotypic with that of Cs3[CoCl4]Cl (space group: 14/mcm, Z = 4). The structure of K3MnH5 contains isolated [MnH4]2?-tetrahedra and additional hydrogen ions which are exclusively coordinated by potassium cations. The magnetic susceptibilities show Curie-Weiss behaviour. At temperatures below 50 K there are obviously antiferromagnetic interactions. 相似文献
7.
Meinhard Wlaschek Gudrun Heinen Arndt Poswig Agatha Schwarz Thomas Krieg Karin Scharffetter-Kochanek 《Photochemistry and photobiology》1994,59(5):550-556
Abstract— Previous work has shown that fibroblast-derived collagenase/matrix-metalloproteinase-1(MMP–1), responsible for the breakdown of dermal interstitial collagen, was dose-dependently induced in vitro and in vivo by UVA irradiation and this induction was at least partly mediated byinterleukin–6(IL–6). We here provide evidence that UVA-inducedIL–1α andIL–1β play a central role in the induction of the synthesis both ofIL–6 and collagenase/MMP–1. In contrast to the late increase ofIL–1α andIL–1β mRNA levels at 6 h postirradiation, bioactivity ofIL–1 is already detectable at 1 h postirradiation. This early peak ofIL–1 bioactivity appears to be responsible for the induction ofIL–6 synthesis and together withIL–6 lead to an increase of the steady-state mRNA level of collagenase/MMP–1 as deduced from studies usingIL–1α andIL–1β antisense oligonucleotides or neutralizing antibodies againstIL–1α andIL–1β Besides the early posttranslationally controlled release of intracellularIL–1, a latter pretranslationally controlled synthesis and release ofIL–1 perpetuates the UV response. From these data we suggest a UV-induced cytokine network consisting ofIL–1α,IL–1β andIL–6, which via interrelated autocrine loops induce collagenase/MMP–1 and thus may contribute to the loss of interstitial collagen in cutaneous photoaging. 相似文献
8.
Synthesis and Structure of Li3RhH6 — a Ternary Hydride with Isolated [RhH6]3? Octahedra The ternary rhodium hydride Li3RhH6 was synthesized by the reaction of lithium hydride with rhodium under a hydrogen pressure of 80 bar. X-ray investigations on powdered samples and an elastic neutron diffraction experiment on the deuterated compound led to the complete structure determination (space group: Pnma, Z = 4). The atomic arrangement is isotypic to the Na3RhH6 structure type. The crystal structure contains isolated [RhH6]3? octahedra, which are separated by the lithium ions. 相似文献
9.
Gudrun Albrecht 《Journal of Geometry》1994,50(1-2):1-10
In 1809 J. IVORY found a distance relation between any two confocal ellipsoids in Euclidean space E3. After that, the theorem of IVORY has been formulated for any two nondegenerate confocal quadrics of the same type. In this paper we succeed in completing these results and in formulating and proving them uniformly for any two quadrics of the same type belonging to a general system of confocal quadrics.
Herrn Prof. Dr. Oswald Giering zum 60. Geburtstag gewidmet 相似文献
Herrn Prof. Dr. Oswald Giering zum 60. Geburtstag gewidmet 相似文献
10.
The Boussinesq approximation, where the viscosity depends polynomially on the shear rate, finds more and more frequent use in geological practice. In the paper, this modified Boussinesq approximation is investigated as a dynamical system for which the existence of a global attractor is proved. Finally, a new criterion for estimating the fractal dimension of invariant sets is formulated and its application to the problem under consideration is illustrated. 相似文献