全文获取类型
收费全文 | 655篇 |
免费 | 19篇 |
国内免费 | 1篇 |
专业分类
化学 | 547篇 |
晶体学 | 3篇 |
力学 | 5篇 |
数学 | 52篇 |
物理学 | 68篇 |
出版年
2023年 | 6篇 |
2022年 | 18篇 |
2021年 | 23篇 |
2020年 | 21篇 |
2019年 | 19篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 26篇 |
2015年 | 17篇 |
2014年 | 24篇 |
2013年 | 45篇 |
2012年 | 36篇 |
2011年 | 49篇 |
2010年 | 21篇 |
2009年 | 23篇 |
2008年 | 41篇 |
2007年 | 38篇 |
2006年 | 32篇 |
2005年 | 49篇 |
2004年 | 32篇 |
2003年 | 26篇 |
2002年 | 22篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1981年 | 5篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有675条查询结果,搜索用时 15 毫秒
51.
52.
Elisabeth Holder Veronica Marin Alexander Alexeev Ulrich S. Schubert 《Journal of polymer science. Part A, Polymer chemistry》2005,43(13):2765-2776
A set of novel greenish‐yellow‐, yellow‐, and orange‐light‐emitting polymeric iridium(III) complexes were synthesized with the bridge‐splitting method. The respective dimeric precursor complexes, [Ir(ppy)2‐μ‐Cl]2 (ppy = 2‐phenylpyridine) and [Ir(ppy? CHO)2‐μ‐Cl]2 [ppy? CHO = 4‐(2‐pyridyl)benzaldehyde], were coordinated to 2,2′‐bipyridine carrying poly(ε‐caprolactone) tails. The resulting emissive polymers were characterized with one‐dimensional (1H) and two‐dimensional (1H? 1H correlation spectroscopy) nuclear magnetic resonance and infrared spectroscopy, gel permeation chromatography, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, and the successful coordination of the iridium(III) centers to the 2,2′‐bipyridine macroligand was revealed. The thermal behavior was studied with differential scanning calorimetry and correlated with atomic force microscopy. Furthermore, the quantitative coordination was verified by both the photophysical and electrochemical properties of the mononuclear iridium(III) compounds. The photoluminescence spectra showed strong emissions at 535 and 570 nm. The color shifts depended on the substituents of the cyclometallating ligands. Cyclic voltammetry gave oxidation potentials of 1.23 V and 1.46 V. Upon the excitation of the films at 365 nm, yellow light was observed, and this could allow potential applications in light‐emitting devices. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2765–2776, 2005 相似文献
53.
Growth of metal-organic frameworks on polymer surfaces 总被引:1,自引:0,他引:1
Centrone A Yang Y Speakman S Bromberg L Rutledge GC Hatton TA 《Journal of the American Chemical Society》2010,132(44):15687-15691
Polymer substrates have been functionalized with a MOF material (MIL-47) synthesized directly on polyacrylonitrile using in situ microwave irradiation. The growth of MIL-47 on these substrates was studied as a function of microwave irradiation time using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The conversion of nitrile to carboxylic acid groups on the PAN surface was necessary for the growth of MIL-47 on the substrate. MIL-47 crystals grew over time at the expense of a related disordered precursor phase, which lacks the long-range order of MIL-47. This work paves the way for the development of a new class of hybrid MOF-polymer materials that will extend the applications of MOFs to fields such as membrane separations, filtration, and protective textiles. 相似文献
54.
Jung A. Jung Young Baek Kim Young A. Kim Seung Bum Ryu Veronica Kim 《Journal of nanoparticle research》2011,13(6):2361-2374
Functional spherical solid and hollow particles of polysilsesquioxanes (PSQs) containing amine, thiol, and vinyl groups were
prepared by polymerizing organotrialkoxysilanes (OTASs) containing corresponding chemical groups. Fluorescent PSQ particles
were prepared by physically entrapping Rhodamine 6G, Coumarin 7, and Fluoresceine sodium salts. The intensity of fluorescent
light increased initially with increasing amount of entrapped fluorophores and then leveled off or decreased slightly after
reaching a maximum value. PSQ particles containing gold nanoparticles (GNPs), both inside and on the surface, were prepared
by the in situ reduction of gold ions by the PSQ particles. When the reduction reaction was carried out for extended periods
of time, the GNP that had formed inside the poly(3-mercaptopropyl)silsesquioxane (PMPSQ) and polyvinylsilsesequioxane (PVSQ)
particles underwent interesting morphological changes. PSQ particles containing amine and thiol groups fixed the GNPs on the
surface, which could be utilized further in binding amine-modified oligo-DNA strands. The aggregation of PSQ/GNP particles
combined with complementary oligo-DNA strands was examined to demonstrate that these particles could be applied to DNA assays
and isolation. The particles were characterized by scanning electron microscopy, transmission electron microscopy, solid state
nuclear magnetic resonance spectroscopy, ultraviolet/visible spectroscopy, and fluorescence microscopy. 相似文献
55.
Cyclic voltammetry, galvanostatic charge?Cdischarge technique, potentiostatic intermittent titration technique (PITT), and electrochemical impedance spectroscopy (EIS) were used to study the behavior of a LiMn1.95Cr0.05O4 (substituted lithium?Cmanganese spinel) electrode in nonaqueous electrolytes at 25 °C. Quantitative and qualitative changes of the electrode transport parameters as functions of lithium concentration were analyzed. Several equivalent circuits are discussed; the results obtained by different methods are compared. The PITT and EIS results are in good agreement; the chemical diffusion coefficient D varies within 10?14?C10?9 cm2 s?1 depending on the lithium content in the LixMn1.95Cr0.05O4 electrode. 相似文献
56.
57.
58.
Richard C. Cambie Sally J. Janssen Peter S. Rutledge Paul D. Woodgate 《Journal of organometallic chemistry》1991,420(3):387-418
Double nucleophilic aromatic substitution reactions between (cyclopentadienyl)(η6-1,2-dichlorobenzene)iron(1 + ) salts and substituted 1,2benzenediols have been carried out under mild conditions to prepare [η6-dibenzo[b,e][1,4]dioxin]iron(1 + ) complexes functionalized in the 1- or 2-position with an alkyl, aldehyde, carboxylic acid, methoxycarbonyl, carboxamide, or hydroxy group. 3-Methyl- and 4-methyl-(η6-1,2-dichlorobenzene)iron complexes were treated with substituted 1,2-benzenediols to effect functionalization of both aromatic rings of the heterocycle. The dibenzodioxin ligands were liberated routinely by irradiation with ultraviolet light. Directed deprotonation of the free functionalized dibenzodioxins with an alkyllithium reagent followed by quenching with a variety of electrophiles yielded further derivatives, including two new isoindolone systems. 相似文献
59.
Pons M Ahufinger V Wunderlich C Sanpera A Braungardt S Sen De A Sen U Lewenstein M 《Physical review letters》2007,98(2):023003
We demonstrate the possibility of realizing a neural network in a chain of trapped ions with induced long range interactions. Such models permit one to store information distributed over the whole system. The storage capacity of such a network, which depends on the phonon spectrum of the system, can be controlled by changing the external trapping potential. We analyze the implementation of error resistant universal quantum information processing in such systems. 相似文献