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1.
Seokwoo Kang Hayoon Lee Hyocheol Jung Donghee Shin Miyeon Park 《Molecular Crystals and Liquid Crystals》2018,662(1):96-101
ABSTRACTTIACA-I, TIACA-II were synthesized by changing the substitution position of the imidazole group in the diazocine core. TIACA-I, TIACA-II in the film state showed absorption in the range of 354 to 392 nm and exhibited blue photoluminescence (PL) emissions at 448 and 462 nm, respectively. The PL wavelength of TIACA-II is red-shifted by 14 nm than that of TIACA-I due to the electron-donating intensity depending on the position of the imidazole group. The use of TIACA-II in a non-doped OLED device resulted in blue emission with current efficiency of 2.84 cd/A and CIE of (0.15, 0.18). 相似文献
2.
Rational design of methacrylate monomers containing oxadiazole moieties for single‐layer organic light emitting devices 下载免费PDF全文
Bogdan Zdyrko Yuriy Bandera Volodymyr Tsyalkovsky Christopher F. Huebner Jamie A. Shetzline Parul Rungta Ryan D. Roeder Charles Tonkin Stephen E. Creager Stephen H. Foulger 《Journal of Polymer Science.Polymer Physics》2015,53(23):1663-1673
Methacrylate derived monomers functionalized with pendant oxadiazole moieties were synthesized and copolymerized with carbazole containing monomers to form polymers with electron and hole transporting fragments in the same molecule. Substituents on the oxidazole moiety were varied with the purpose of bandgap tuning and performance optimization when employed in single‐layer organic light emitting devices (OLED). Quantum mechanical calculations of the HOMO‐LUMO levels of the oxidazole derivatives were used to down‐select promising candidates for chemical synthesis and testing in single‐layer OLEDs. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1663–1673 相似文献
3.
Palladium‐Catalyzed N‐Arylation of Iminodibenzyls and Iminostilbenes with Aryl‐ and Heteroaryl Halides 下载免费PDF全文
Dr. Wenliang Huang Prof. Stephen L. Buchwald 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(40):14186-14189
Compounds containing the iminodibenzyl and iminostilbene ring systems are prevalent in medicinal targets and functional materials. Herein, we report palladium‐catalyzed conditions for the N‐arylation of these ring systems. This protocol could be applied to a variety of (hetero)aryl chloride and bromide substrates, including ones, which are sterically hindered or those containing a variety of functional groups. Use of the fourth‐generation palladacycle precatalyst gave good to excellent yields by using low palladium‐catalyst loadings (0.1 to 1 mol %). 相似文献
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A recent experiment [Angew. Chem. Int. Ed. 2017 , 56, 722–727] found that a (1 : 9) blend film of two anthracene derivatives, 2-fluorenyl-2-anthracene ( FlAnt ) and 2-anthryl-2-anthracence ( 2 A ), exhibit both efficient white light emission and high hole mobility, thus promising for organic light-emitting transistors (OLETs). Employing quantum chemistry at the polarizable continuum model (PCM) and the quantum mechanics/molecular mechanics (QM/MM) levels, we investigated the excited-state structures, optical spectra, band structure and the carrier mobility for FlAnt and 2 A from solution to aggregate phases. We suggest using the ratio of intermolecular excitonic coupling J and intramolecular excited state relaxation energy E to judge the bathochromic shift in optical emission in aggregates. For FlAnt , ρ=J/E is calculated to be less than 0.17, a critical value we identified earlier, and the spectra in solution and aggregate phases present quite similar features (blue emission). However, ρ is ∼0.5 for 2 A systems, and the calculated emission in the aggregate phase exhibits a remarkable bathochromic shift. In addition, the 0–0 emission is strongly suppressed in the herringbone stacking. These observations justify the experimental findings that (i) 2 A is blue emissive in solution but yellow-green in the aggregate phase, whereas FlAnt is always blue, and (ii) the blend of them show white emission. By using the “quantum nuclear tunneling” model we proposed earlier, we found the hole mobility for FlAnt and 2 A are 0.5 and 4.2 cm2 V−1 s−1, respectively, indicating both are good hole transport materials. 相似文献
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Selective Probing of Gaseous Ammonia Using Red‐Emitting Carbon Dots Based on an Interfacial Response Mechanism 下载免费PDF全文
Dr. Bang‐Ping Jiang Bo Zhou Prof. Dr. Xing‐Can Shen Yun‐Xiang Yu Dr. Shi‐Chen Ji Chang‐Chun Wen Prof. Dr. Hong Liang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(52):18993-18999
Solid‐state fluorescence sensing is one of the most appealing detection techniques because of its simplicity and convenience in practical operation. Herein, we report the development of a red‐emitting carbon dots (RCDs)‐based material as a solid‐state fluorescence sensor for the selective probing of gaseous ammonia. The RCDs were prepared by a low‐cost, one‐step carbonization method using sugar cane bagasse as the carbon precursor. The pristine RCDs were then directly coated on polyvinylidene fluoride membrane to produce a new fluorescence sensor capable of selectively distinguishing toxic gaseous ammonia from other analyte vapors through sensitive fluorescence quenching with a low detection limit. More importantly, the interfacial response mechanism occurring on the surface of the RCDs has been studied by X‐ray photoelectron spectroscopy, Fourier‐transform infrared spectroscopy, and Raman measurements. The results indicate that fluorescence quenching in the RCDs might result from ammonia‐induced Michael addition through insertion of N into the C?C group and deprotonation of the carboxyl group. To the best of our knowledge, this is the first report that provides clear insight into the mechanism of surface chemistry on CDs in the solid state. 相似文献
8.
Prof. Dr. Suning Wang Deng‐Tao Yang Jiasheng Lu Hiroyuki Shimogawa Prof. Dr. Shaolong Gong Xiang Wang Soren K. Mellerup Prof. Dr. Atsushi Wakamiya Dr. Yi‐Lu Chang Prof. Dr. Chuluo Yang Prof. Dr. Zheng‐Hong Lu 《Angewandte Chemie (International ed. in English)》2015,54(50):15074-15078
New BN‐heterocyclic compounds have been found to undergo double arene photoelimination, forming rare yellow fluorescent BN‐pyrenes that contain two B? N units. Most significant is the discovery that the double arene elimination can also be driven by excitons generated electrically within electroluminescent (EL) devices, enabling the in situ solid‐state conversion of BN‐heterocycles to BN‐pyrenes and the use of BN‐pyrenes as emitters for EL devices. The in situ exciton‐driven elimination (EDE) phenomenon has also been observed for other BN‐heterocycles. 相似文献
9.
Young‐Inn Kim Young‐Kwang Song Daeyoung Kim Sung Kwon Kang 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(10):908-911
Metal complexes with Schiff base ligands have been suggested as potential phosphors in electroluminescent devices. In the title complex, tetrakis[6‐methyl‐2‐({[(pyridin‐2‐yl)methyl]imino}methyl)phenolato‐1:2κ8N,N′,O:O;3:2κ8N,N′,O:O]trizinc(II) hexafluoridophosphate methanol monosolvate, [Zn3(C14H13N2O)4](PF6)2·CH3OH, the ZnII cations adopt both six‐ and four‐coordinate geometries involving the N and O atoms of tetradentate 6‐methyl‐2‐({[(pyridin‐2‐yl)methyl]imino}methyl)phenolate ligands. Two terminal ZnII cations adopt distorted octahedral geometries and the central ZnII cation adopts a distorted tetrahedral geometry. The O atoms of the phenolate ligands bridge three ZnII cations, forming a dicationic trinuclear metal cluster. The title complex exhibits a strong emission at 469 nm with a quantum yield of 15.5%. 相似文献
10.
Enhanced Static Modulated Fourier Transform Spectrometer for Fast Approximation in Field Application
We discuss the data sampling frequency, the spectral resolution, and the limit for non-aliasing in the static modulated Fourier transform spectrometer based on a modified Sagnac interferometer. The measurement was performed in a very short 4 ms, which is applicable for real time field operation. The improved spectrometer characteristics were used to investigate the spectral properties of an InGaAs light emitting diode. In addition, The measured spectral peak was shifted from 6420 cm−1 to 6365 cm−1, as the temperature increased from 25 °C to 40 °C, when the operating current is fixed to be 0.55 A. As the applied current increased from 0.30 A to 0.55 A at room temperature, the spectral width was broadened from 316 cm−1 to 384 cm−1. Compared to the conventional Fourier transform spectrometer, the measured spectral width by the static modulated Fourier transform spectrometer showed a deviation less than 10%, and the spectral peak shift according to the temperature rise showed a difference within 2%. 相似文献