全文获取类型
收费全文 | 493篇 |
免费 | 11篇 |
国内免费 | 3篇 |
专业分类
化学 | 288篇 |
晶体学 | 3篇 |
力学 | 16篇 |
数学 | 112篇 |
物理学 | 88篇 |
出版年
2023年 | 3篇 |
2022年 | 12篇 |
2021年 | 12篇 |
2020年 | 3篇 |
2019年 | 12篇 |
2018年 | 14篇 |
2017年 | 13篇 |
2016年 | 16篇 |
2015年 | 17篇 |
2014年 | 20篇 |
2013年 | 35篇 |
2012年 | 45篇 |
2011年 | 38篇 |
2010年 | 34篇 |
2009年 | 24篇 |
2008年 | 20篇 |
2007年 | 32篇 |
2006年 | 22篇 |
2005年 | 13篇 |
2004年 | 16篇 |
2003年 | 16篇 |
2002年 | 13篇 |
2001年 | 5篇 |
2000年 | 10篇 |
1999年 | 3篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有507条查询结果,搜索用时 15 毫秒
21.
Yellow-orange single crystals of CuSbF6, were prepared by reacting Cu wire (∼10 mmol) with SbF5 (∼3 mmol) in liquid anhydrous hydrogen fluoride (aHF) and by reduction of Cu(SbF6)2 with Cu metal in aHF. CuSbF6 crystallizes rhombohedral at 296 K with the LiSbF6 structure type, with a = 530.4(4) pm, c = 1453(1) pm and Z = 3, space group R (no. 148). The structure is dominated by isolated layers of regular [SbF6]− octahedra and Cu+ cations.An attempt to prepare CuF by reaction between CuSbF6 and CsF in aHF at ∼190 K failed. Instead of CuF, a mixture of Cu and CuF2 was obtained. 相似文献
22.
Mile B. Djurdjevic Gerhard Huber Zoran Odanovic 《Journal of Thermal Analysis and Calorimetry》2013,111(2):1365-1373
Available databases presently used by commercial simulation software packages for the aluminum casting industry are usually armed with material properties for only a few selected standard alloys. In the case of other alloys with different chemical compositions and refinement or modification treatment, thermal analysis could be an invaluable tool to gain necessary properties. The aim of this article is to demonstrate the potential application of the cooling curve analysis in the existing simulation software by improving its accuracy. 相似文献
23.
The reaction between AgBF4 and excess of SbF5 in anhydrous hydrogen fluoride (aHF) yields the white solid AgSb2F11 after the solvent and the excess of SbF5 have been pumped off. Reaction between equimolar amounts of AgSb2F11 and AgBF4 yields AgSbF6. Meanwhile, oxidation of solvolyzed AgSb2F11 in aHF by elemental fluorine yields a clear blue solution of solvated Ag(II) cations and SbF6- anions. AgSb2F11 is orthorhombic, at 250 K, Pbca, with a=1091.80(7) pm, b=1246.28(8) pm, c=3880.2(3) pm, V=5.2797(6) nm3, and Z=24. The crystal structure of AgSb2F11 is related to the already known crystal structure of H3OSb2F11. Vibrational spectra of AgSb2F11 entirely match the literature-reported vibrational spectra of beta-Ag(SbF6)2, for which a formulation of a mixed-valence AgI/AgIII compound was suggested (AgIAgIII(SbF6)4). On the basis of obtained results it can be concluded that previously reported beta-Ag(SbF6)2 is in fact Ag(I) compound with composition AgSb2F11. 相似文献
24.
Bajuk-Bogdanović Danica Holclajtner-Antunović Ivanka Jovanović Zoran Mravik Željko Krstić Jugoslav Uskoković-Marković Snežana Vujković Milica 《Journal of Solid State Electrochemistry》2019,23(9):2747-2758
Journal of Solid State Electrochemistry - The synergistic effects between two Keggin-type heteropoly acids (HPAs) and carbon surface were examined and elucidated. An improved high rate capability... 相似文献
25.
Thomas R. Gengenbach Zoran R. Vasic Ronald C. Chatelier Hans J. Griesser 《Plasmas and Polymers》1996,1(3):207-228
Angle-dependent XPS and air/water contact angle (CA) measurements were performed on specimens of n-hexane plasma polymers
at various times after fabrication in order to monitor the aging of the surfaces in contact with air. XPS revealed incorporation
of oxygen over extended periods of time. The depth distribution of O changed in the course of aging. CAs decreased over the
first 3 weeks, then increased again, and finally stabilized at 5 weeks. These results were interpreted in terms of two concurrent
processes: spontaneous oxidation (initiated by trapped radicals), which increased the surface polarity, and surface restructuring,
which caused the partial removal of polar groups from the interface with air. The former process made a larger contribution
to the overall aging of the surfaces but the latter process also contributed measurably. Over the first 3 weeks, oxidation
was rapid and surface restructuring was not competitive. Subsequently, the oxygen uptake slowed down markedly, and the outermost
surface layers became oxygen depleted relative to the deeper layers, due to partial surface reorientation. The surface topography,
assessed by STM, did not change on aging. The aging of n-hexane plasma polymer surfaces thus is due to superimposed effects
arising from post-deposition oxidative processes and partial surface reorientation. 相似文献
26.
Integrated Transmission Electron and Single‐Molecule Fluorescence Microscopy Correlates Reactivity with Ultrastructure in a Single Catalyst Particle 下载免费PDF全文
Frank C. Hendriks Sajjad Mohammadian Dr. Zoran Ristanović Dr. Sam Kalirai Dr. Florian Meirer Prof. Dr. Eelco T. C. Vogt Dr. Pieter C. A. Bruijnincx Prof. Dr. Hans C. Gerritsen Prof. Dr. Bert M. Weckhuysen 《Angewandte Chemie (International ed. in English)》2018,57(1):257-261
Establishing structure–activity relationships in complex, hierarchically structured nanomaterials, such as fluid catalytic cracking (FCC) catalysts, requires characterization with complementary, correlated analysis techniques. An integrated setup has been developed to perform transmission electron microscopy (TEM) and single‐molecule fluorescence (SMF) microscopy on such nanostructured samples. Correlated structure–reactivity information was obtained for 100 nm thin, microtomed sections of a single FCC catalyst particle using this novel SMF‐TEM high‐resolution combination. High reactivity in a thiophene oligomerization probe reaction correlated well with TEM‐derived zeolite locations, while matrix components, such as clay and amorphous binder material, were found not to display activity. Differences in fluorescence intensity were also observed within and between distinct zeolite aggregate domains, indicating that not all zeolite domains are equally active. 相似文献
27.
Back Cover: Integrated Transmission Electron and Single‐Molecule Fluorescence Microscopy Correlates Reactivity with Ultrastructure in a Single Catalyst Particle (Angew. Chem. Int. Ed. 1/2018) 下载免费PDF全文
28.
Zoran D. Mitrovi? 《Nonlinear Analysis: Theory, Methods & Applications》2010,72(11):4049-926
We prove a coupled best approximations theorem in normed spaces. Also, we derive the results on coupled coincidence points and coupled fixed points, which were introduced by Lakshmikantham and ?iri? [V. Lakshmikantham, LJ. ?iri?, Coupled fixed point theorems for nonlinear contractions in partially ordered metric spaces, Nonlinear Anal. TMA, 70 (2009) 4341-4349]. 相似文献
29.
Zoran Stanić 《Linear algebra and its applications》2012,437(7):1812-1820
We determine all trees whose second largest eigenvalue does not exceed . Next, we consider two classes of bipartite graphs, regular and semiregular, with small number of distinct eigenvalues. For all graphs considered we determine those whose second largest eigenvalue is equal to . Some additional results are also given. 相似文献
30.
Zoran Kadelburg Stojan Radenović Vladimir Rakočević 《Applied Mathematics Letters》2009,22(11):1674-1679
Recently, D. Ili? and V. Rako?evi? [D. Ili?, V. Rako?evi?, Quasi-contraction on a cone metric space, Appl. Math. Lett. (2008) doi:10.1016/j.aml.2008.08.011] proved a fixed point theorem for quasi-contractive mappings in cone metric spaces when the underlying cone is normal. The aim of this paper is to prove this and some related results without using the normality condition. 相似文献