全文获取类型
收费全文 | 949篇 |
免费 | 23篇 |
国内免费 | 11篇 |
专业分类
化学 | 617篇 |
晶体学 | 20篇 |
力学 | 18篇 |
数学 | 109篇 |
物理学 | 219篇 |
出版年
2022年 | 8篇 |
2020年 | 10篇 |
2019年 | 9篇 |
2017年 | 8篇 |
2016年 | 14篇 |
2015年 | 19篇 |
2014年 | 17篇 |
2013年 | 32篇 |
2012年 | 37篇 |
2011年 | 30篇 |
2010年 | 19篇 |
2009年 | 19篇 |
2008年 | 19篇 |
2007年 | 36篇 |
2006年 | 30篇 |
2005年 | 35篇 |
2004年 | 36篇 |
2003年 | 37篇 |
2002年 | 17篇 |
2001年 | 18篇 |
2000年 | 26篇 |
1999年 | 22篇 |
1998年 | 13篇 |
1997年 | 19篇 |
1996年 | 18篇 |
1995年 | 12篇 |
1994年 | 14篇 |
1993年 | 12篇 |
1992年 | 12篇 |
1991年 | 15篇 |
1990年 | 16篇 |
1989年 | 15篇 |
1988年 | 11篇 |
1986年 | 13篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 12篇 |
1981年 | 9篇 |
1979年 | 9篇 |
1978年 | 13篇 |
1977年 | 8篇 |
1976年 | 8篇 |
1975年 | 9篇 |
1974年 | 9篇 |
1972年 | 9篇 |
1968年 | 13篇 |
1966年 | 10篇 |
1965年 | 17篇 |
1964年 | 11篇 |
1962年 | 8篇 |
排序方式: 共有983条查询结果,搜索用时 125 毫秒
91.
Krause KM Vick DW Malac M Brett MJ 《Langmuir : the ACS journal of surfaces and colloids》2010,26(22):17558-17567
The high surface area, large aspect ratio, and porous nature of nanorod arrays make them excellent foundation materials for many devices. Of the many synthesis techniques for forming nanorods, glancing angle deposition (GLAD) offers one of the more straightforward and flexible methods for ensuring control of alignment, porosity, and architecture of the nanorods. Here we demonstrate the first use of a dual-beam (focused ion beam (FIB) combined with scanning electron microscopy (SEM)) instrument to section and image the internal morphology of a nanorod array fabricated using the GLAD technique. We have used the FIB-SEM to reconstruct the 3D composition of TiO(2) nanorods, allowing us to visualize for the first time the core structures of many potential devices. We have also been able to probe the relationship between critical parameters such as diameter (w(act)), internanorod spacing (ν(act)), center-to-center spacing (c(act)), and nanorod population density (d(act)) and the depth of the nanocolumn (t) for a single homogeneous structure. A continuous data set was obtained from a single 5-μm-thick GLAD film, avoiding the artifacts arising from the analysis of the top surfaces of multiple samples of varying thicknesses. An analysis of the acquired sectioned data has allowed us to determine that the critical nanocolumn parameters follow a power-law scaling trend with w(act) = 9.4t(0.35) nm, ν(act) = 15.2t(0.25) nm, c(act) = 24.8t(0.31) nm, and d(act) = 3402t(-0.65) columns μm(-2). Using the FIB/SEM images acquired for the TiO(2) nanorods, we have also investigated the evolution of individual nanocolumns and have observed that bifurcation and branching play a significant role in the extinction or survival of these nanorods. These findings will allow for the optimization of nanorod properties for device applications. Also, the FIB sectioning and reconstruction process developed here will permit for the investigation of nanorod arrays formed from a range of synthesis techniques and materials. 相似文献
92.
Verch A Hahn H Krause E Cölfen H Börner HG 《Chemical communications (Cambridge, England)》2010,46(47):8938-8940
Self-assembled peptide-polymer nanotapes of poly(ethylene oxide)-peptide conjugates are modified by a simple amine-azide transfer to create azide-containing nanofibres, which provide a platform for modular functionalization as demonstrated by the introduction of different carboxyl bearing entities to modulate the calcium binding properties of the nanotapes. 相似文献
93.
Pullback attractors of non-autonomous stochastic degenerate parabolic equations on unbounded domains
This paper is concerned with pullback attractors of the stochastic p -Laplace equation defined on the entire space Rn. We first establish the asymptotic compactness of the equation in L2(Rn) and then prove the existence and uniqueness of non-autonomous random attractors. This attractor is pathwise periodic if the non-autonomous deterministic forcing is time periodic. The difficulty of non-compactness of Sobolev embeddings on Rn is overcome by the uniform smallness of solutions outside a bounded domain. 相似文献
94.
Pre-conditioning is usually not considered in classical lifetime prediction analyses. The strong material softening observed in rubber materials, however, makes one expect a strong influence of the pre-conditioning on the lifetime. For this contribution, experimental tests were carried out to verify and further investigate, how the pre-loading affects the lifetime of filled natural rubber. Comparing the experimental results with according simulations using the MOdel of Rubber PHenomenology (MORPH) [1, 2] it is found that even though the simulation shows an extended lifetime with higher pre-straining, the experimental data shows no significant influence of this pre-conditioning. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
95.
Ansgar J��ngel Stefan Krause Paola Pietra 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2011,62(4):623-639
Diffusive moment equations with an arbitrary number of moments are formally derived from the semiconductor Boltzmann equation employing a moment method and a Chapman?CEnskog expansion. The moment equations are closed by employing a generalized Fermi?CDirac distribution function obtained from entropy maximization. The current densities allow for a drift-diffusion-type formulation or a ??symmetrized?? formulation, using dual-entropy variables from nonequilibrium thermodynamics. Furthermore, drift-diffusion and new energy-transport equations based on Fermi?CDirac statistics are obtained and their degeneracy limit is studied. 相似文献
96.
97.
E. Krause 《Monatshefte für Chemie / Chemical Monthly》1908,29(10):1119-1130
Ohne Zusammenfassung 相似文献
98.
99.
100.
W. Moritz I. Gerhardt D. Roden M. Xu S. Krause 《Analytical and bioanalytical chemistry》2000,367(4):329-333
A miniaturized optical set-up based on a CD-ROM player optic was developed for LAPS (light addressable potentiometric sensors). A focus of 2.6 μm was achieved using this easy to handle device. The lateral resolution of LAPS measurements can be improved by using GaAs as the semiconductor material instead of Si. The diffusion length of the minority charge carriers was determined to be smaller than 3.1 μm. A new method called SPIM (scanning photo-induced impedance microscopy) is described. Using this technique, the impedance of thin films can be measured with lateral resolution. 相似文献