全文获取类型
收费全文 | 203篇 |
免费 | 7篇 |
国内免费 | 2篇 |
专业分类
化学 | 106篇 |
晶体学 | 1篇 |
力学 | 9篇 |
数学 | 62篇 |
物理学 | 34篇 |
出版年
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 7篇 |
2015年 | 3篇 |
2014年 | 8篇 |
2013年 | 12篇 |
2012年 | 14篇 |
2011年 | 11篇 |
2010年 | 13篇 |
2009年 | 8篇 |
2008年 | 6篇 |
2007年 | 14篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 7篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1972年 | 1篇 |
1968年 | 1篇 |
1930年 | 1篇 |
排序方式: 共有212条查询结果,搜索用时 15 毫秒
31.
Caterina Rinaudo Mario Allegrina Elisa Fornero Maya Musa Alessandro Croce Donata Bellis 《Journal of Raman spectroscopy : JRS》2010,41(1):27-32
Histological sections of a patient affected by an important respiratory disease were analysed firstly by optical microscope(OM)—crossed polarisers—to identify the presence of incorporated inorganic particles, with particular attention to the fibrous ones. Then, the particles/fibres that were found were studied both with micro‐Raman spectroscopy and variable‐pressure scanning electron microscopy with energy‐dispersive spectroscopy (VP‐SEM/EDS). The two techniques allowed the in situ characterisation of the inorganic phases without disintegration of the organic matter. Micro‐Raman spectroscopy was able to identify the vibrating chemical groups of the mineral phase associated with the inorganic grain while the crystalline structure was preserved by the biological system. The VP‐SEM/EDS characterisation, defining the elemental chemical composition of the analysed particle/fibre, allowed confirmation of the mineral phase deducible from spectroscopic data or its identification with certainty when the spectroscopic data were not exhaustive. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
32.
V. Rossi Albertini G. B. Appetecchi R. Caminiti F. Croce F. Cilloco C. Sadun 《Journal of Macromolecular Science: Physics》2013,52(5):629-641
The crystallization kinetics of poly(ethylene oxide) doped with various alkaline perchlorate salts were measured at room temperature by means of the new energy dispersive x-ray diffraction method for the phase transition. The experimental points of the transformation coordinate were fitted using the phenomenological Liquori-Tripiciano law, the parameters of which were evaluated for each case. The influence of the concentration and of the cation dimensions on the crystallization rate is discussed. Further details about the application of this nonconventional diffractometric technique to polymers are also reported, as is an intuitive model for describing the method. 相似文献
33.
This paper addresses the topic of classifying financial time series in a fuzzy framework proposing two fuzzy clustering models both based on GARCH models. In general clustering of financial time series, due to their peculiar features, needs the definition of suitable distance measures. At this aim, the first fuzzy clustering model exploits the autoregressive representation of GARCH models and employs, in the framework of a partitioning around medoids algorithm, the classical autoregressive metric. The second fuzzy clustering model, also based on partitioning around medoids algorithm, uses the Caiado distance, a Mahalanobis-like distance, based on estimated GARCH parameters and covariances that takes into account the information about the volatility structure of time series. In order to illustrate the merits of the proposed fuzzy approaches an application to the problem of classifying 29 time series of Euro exchange rates against international currencies is presented and discussed, also comparing the fuzzy models with their crisp version. 相似文献
34.
35.
Maroni Fabio Bruni Pantaleone Suzuki Naoki Aihara Yuichi Croce Fausto 《Journal of Solid State Electrochemistry》2019,23(6):1697-1703
Journal of Solid State Electrochemistry - All-solid-state batteries represent the next generation of electrochemical energy storage systems. A tin-carbon nanocomposite material is prepared by the... 相似文献
36.
Lucia Giorgetti Gianluca Giorgi Edoardo Cherubini Pier Giovanni Gervasi Clara Maria Della Croce Vincenzo Longo 《Natural product research》2018,32(14):1617-1626
We report the spectrophotometric determination of total polyphenols, flavonoids, glucosinolates and antioxidant activity in seeds, seedlings and leaves of Tuscan black kale. The highest content of phytochemicals was observed in 10 days sprouts and antioxidant activity was maximum in 2, 4 days seedlings. Identification and characterisation of phytochemicals were performed by mass spectrometry (MS), high resolution and tandem MS with electrospray ionisation mode. Low-molecular-weight metabolites were evidenced in seeds while metabolites at high m/z range were detected in cotyledons and leaves. MS spectra evidenced different phenolic compounds (flavonoid caffeoyl glucose, hydroxycinnamic acid sinapine) and glucosinolates (glucoerucin, glucobrassicin and glucoraphanin) in function of developmental stage; galactolipids ω3 and ω6 were observed in leaves. Identification of stages with the highest phytochemicals content encourages the consumption of black kale sprouts and young leaves. Our research can support food and pharmaceutical industries for production of health promoting products from black kale. 相似文献
37.
Milanesio M Croce G Viterbo D Pastore HO Mascarenhas AJ Munsignatti EC Meda L 《The journal of physical chemistry. A》2008,112(36):8403-8410
38.
We study the branch of semistable and unstable solutions (i.e., those whose Morse index is at most 1) of the Dirichlet boundary value problem ? Δu = λf(x)/(1 ? u)2 on a bounded domain Ω ? ?N, which models—among other things—a simple electrostatic microelectromechanical system (MEMS) device. We extend the results of 11 relating to the minimal branch, by obtaining compactness along unstable branches for 1 ≤ N ≤ 7 on any domain Ω and for a large class of “permittivity profiles” f. We also show the remarkable fact that powerlike profiles f(x) ? |x|α can push back the critical dimension N = 7 of this problem by establishing compactness for the semistable branch on the unit ball, also for N ≥ 8 and as long as As a byproduct, we are able to follow the second branch of the bifurcation diagram and prove the existence of a second solution for λ in a natural range. In all these results, the conditions on the space dimension and on the power of the profile are essentially sharp. © 2007 Wiley Periodicals, Inc. 相似文献
39.
Denis Bonheure Patrick Habets Franco Obersnel Pierpaolo Omari 《Journal of Differential Equations》2007,243(2):208-237
We discuss existence and multiplicity of positive solutions of the one-dimensional prescribed curvature problem depending on the behaviour at the origin and at infinity of the potential . Besides solutions in W2,1(0,1), we also consider solutions in which are possibly discontinuous at the endpoints of [0,1]. Our approach is essentially variational and is based on a regularization of the action functional associated with the curvature problem. 相似文献
40.
G. B. Appetecchi F. Croce F. Ronci B. Scrosati F. Alessandrini M. Carewska P. P. Prosini 《Ionics》1999,5(1-2):59-63
In the development of rechargeable lithium polymer batteries it is of paramount importance to control the passivation phenomena
occurring at the lithium electrode interface. It is well estabilished that the type and the growth of the lithium passivation
layer is unpredictably influenced by the presence of liquid components and/or impurities in the electrolyte. Therefore, one
approach to improve the stability of the lithium interface is the use of liquid-free, highly pure electrolytes.
The electrochemical properties of a composite polymer electrolyte obtained by hot pressing a mixture of polyethylene oxide
(PEO), a lithium salt (lithium tetrafluoroborate, LiBF4) and a powdered ceramic additive (γ-LiAlO2), will be presented and discussed.
The electrochemical characterization included the determination of the ionic conductivity, the anodic break-down voltage and,
most importantly, the stability of the lithium metal electrode interface and the lithium stripping-plating process efficiency.
The main feature of this dry, true solid-state electrolyte is a very good compatibility with the lithium metal electrode,
demonstrated by a very high lithium cycling efficiency, which approaches a value of 99%.
Paper presented at the 5th Euroconference on Solid State Ionics, Benalmádena, Spain, Sept. 13–20, 1998. 相似文献