全文获取类型
收费全文 | 233篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
化学 | 80篇 |
晶体学 | 1篇 |
力学 | 4篇 |
数学 | 37篇 |
物理学 | 116篇 |
出版年
2022年 | 1篇 |
2021年 | 6篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 4篇 |
2014年 | 7篇 |
2013年 | 16篇 |
2012年 | 10篇 |
2011年 | 16篇 |
2010年 | 6篇 |
2009年 | 10篇 |
2008年 | 14篇 |
2007年 | 19篇 |
2006年 | 11篇 |
2005年 | 16篇 |
2004年 | 10篇 |
2003年 | 8篇 |
2002年 | 6篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有238条查询结果,搜索用时 313 毫秒
31.
32.
Paolo Facchi Rosario Fazio Giuseppe Florio Saverio Pascazio Tetsuya Yoneda 《Foundations of Physics》2006,36(4):500-511
Decoherence is one of the most serious drawback in quantum mechanical applications. We discuss the effects of noise in superconducting devices (Josephson junctions) and suggest a decoherence-control strategy based on the quantum Zeno effect. 相似文献
33.
Nanostructured thin films were deposited by excimer laser ablation of silver targets in controlled atmospheres of He and Ar. The film structural properties were investigated by means of scanning electron microscope and transmission electron microscope imaging. The film growth mechanism was identified as the result of coalescence of nanometric clusters formed during plume flight. Cluster formation involves plume confinement as a consequence of the increased collisional rate among plasma species. Fast photography imaging of the laser-generated silver plasma allowed to identify plasma confinement, shock wave formation and plasma stopping. 相似文献
34.
Binary data represent a very special condition where both measures of distance and co-occurrence can be adopted. Euclidean distance-based non-hierarchical methods, like the k-means algorithm, or one of its versions, can be profitably used. When the number of available attributes increases the global clustering performance usually worsens. In such cases, to enhance group separability it is necessary to remove the irrelevant and redundant noisy information from the data. The present approach belongs to the category of attribute transformation strategy, and combines clustering and factorial techniques to identify attribute associations that characterize one or more homogeneous groups of statistical units. Furthermore, it provides graphical representations that facilitate the interpretation of the results. 相似文献
35.
E. Fazio S. Patanè S. Scibilia A.M. Mezzasalma G. Mondio F. Neri S. Trusso 《Current Applied Physics》2013,13(4):710-716
Nanocrystalline ZnO thin films were grown by means of pulsed laser deposition. The ablation process was carried out at relatively low background oxygen gas pressure (10 Pa) and by varying the substrate temperature up to 600 °C. Information on the structural and morphological properties of the deposited thin films have been obtained by means of X-ray photoelectron, Raman spectroscopies, X-ray diffraction (XRD) and atomic force microscopy (AFM). The results showed that all the deposited films are sub-stoichiometric in oxygen and with a hexagonal wurtzite crystalline structure, characterized by features of some tens of nanometers in size. An improvement of the films' crystalline quality was observed for the deposition temperature of 300 °C while the further increase of the deposition temperature up to 600 °C induces a worsening of the material's structural properties with the development of a large amount of nanoparticle's clusters. The analysis of the XRD patterns shows a growth crystallographic preferential direction as a function of the deposition temperature, in agreement with the appearance of the only E2 optical phonon mode in the Raman spectra. Such findings are compatible with the changes observed in the photoluminescent (PL) optical response and was related to the modification of the ZnO thin film structural quality. 相似文献
36.
E. Fazio E. Piperopoulos S.H. Abdul Rahim M. Lanza G. Faggio G. Mondio F. Neri A.M. Mezzasalma C. Milone S. Santangelo 《Current Applied Physics》2013,13(4):748-752
Pristine and annealed multi-walled C nanotubes are preliminarily tested as catalysts towards the degradation of p-coumaric acid with better performances than the widely used activated carbon. In order to clarify the origin of their different catalytic efficiency, the samples are analysed by means of high-resolution transmission electron microscopy, X-ray photoemission, reflection electron energy loss and micro-Raman spectroscopy. Chemical composition, mass density, bonding configurations and threefold- to fourfold-coordinated carbon bonding ratios are determined. The comparative discussion of the results obtained leads to attribute the higher catalytic activity of the pristine nanotubes to their larger sp2/sp3 carbon bonding fraction and greater amount of oxygen containing functional groups. 相似文献
37.
Barbara Fazio Lorenzo Spadaro Giuseppe Trunfio Jacopo Negro Francesco Arena 《Journal of Raman spectroscopy : JRS》2011,42(7):1583-1588
Composite MnOx CeOx catalysts (Mnat: Ceat = 1) synthesized via the redox and coprecipitation routes were comparatively characterized by micro‐Raman spectroscopy using a laser irradiation power ranging between 0.6 and 4.2 mW. A quasi‐molecular dispersion of the oxide species determines a major and irreversible structural rearrangement of the redox MnOx CeOx system because of severe heating effects for laser power in excess of 0.6 mW. The X‐ray diffraction data of samples calcined in the range of 673 1273 K confirm that the micro‐Raman characterization of the composite MnOx CeOx systems requires an adequate minimization of the irradiation power to prevent the strong sintering and restructuring phenomena due to laser‐heating effects. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
38.
Domenico Franco Giovanna Calabrese Salvatore Petralia Giulia Neri Carmelo Corsaro Lucia Forte Stefano Squarzoni Salvatore Guglielmino Francesco Traina Enza Fazio Sabrina Conoci 《Molecules (Basel, Switzerland)》2021,26(4)
Hydroxyapatite (HA) is the main inorganic mineral that constitutes bone matrix and represents the most used biomaterial for bone regeneration. Over the years, it has been demonstrated that HA exhibits good biocompatibility, osteoconductivity, and osteoinductivity both in vitro and in vivo, and can be prepared by synthetic and natural sources via easy fabrication strategies. However, its low antibacterial property and its fragile nature restricts its usage for bone graft applications. In this study we functionalized a MgHA scaffold with gold nanorods (AuNRs) and evaluated its antibacterial effect against S. aureus and E. coli in both suspension and adhesion and its cytotoxicity over time (1 to 24 days). Results show that the AuNRs nano-functionalization improves the antibacterial activity with 100% bacterial reduction after 24 h. The toxicity study, however, indicates a 4.38-fold cell number decrease at 24 days. Although further optimization on nano-functionalization process are needed for cytotoxicity, these data indicated that Au-NRs nano-functionalization is a very promising method for improving the antibacterial properties of HA. 相似文献
39.
Francesco Mallamace Carmelo Corsaro Enza Fazio Sow-Hsin Chen Domenico Mallamace 《中国科学:物理学 力学 天文学(英文版)》2019,(10)
We study the hydrogen bonds effect on the water density as a function of temperature and pressure from the supercritical region to the metastable supercooled and amorphous phases. We identify two important thermodynamic thresholds, that is P~*2■kbar and T~*■315 K, that separate two different water behaviors in terms of hydrogen bonding capability. For T T~* and P P~* the formation and stability of hydrogen bonded local structures are enhanced. The additional analyses of the proton NMR chemical shift and of the relaxation time confirm this evidence and highlight the structure breaking effects of the pressure. The investigation of both structural and dynamical quantities allow us to draw a complete picture of the water properties in terms of the temperaturepressure dependence of hydrogen bonding. 相似文献
40.
De Fazio D Aquilanti V Cavalli S Aguilar A Lucas JM 《The Journal of chemical physics》2008,129(6):064303
In this paper, we present the results of a theoretical investigation on the dynamics of the title reaction at collision energies below 1.2 kcal/mol using rigorous quantum reactive scattering calculations. Vibrationally resolved integral and differential cross sections, as well as product rotational distributions, have been calculated using two electronically adiabatic potential energy surfaces, developed by us on the basis of semiempirical modifications of the entrance channel. In particular, we focus our attention on the role of the exothermicity and of the exit channel region of the interaction on the experimental observables. From the comparison between the theoretical results, insight about the main mechanisms governing the reaction is extracted, especially regarding the bimodal structure of the HF(v = 2) nascent rotational state distributions. A good overall agreement with molecular beam scattering experiments has been obtained. 相似文献