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141.
Alexander Shyichuk Dmytro Melnyk Jim R. White 《Journal of polymer science. Part A, Polymer chemistry》2003,41(8):1070-1076
Electron structures of alkyl, alkoxy, and peroxy macroradicals for both polypropylene and polystyrene have been studied with quantum chemical methods. The polystyrene tertiary alkoxy macroradical has full delocalization of free spin on a neighboring aromatic ring. In addition, the spin is quite delocalized on polystyrene tertiary alkoxy macroradicals and also on both secondary and tertiary peroxy macroradicals. Such strong delocalization does not occur with polypropylene macroradicals, and it is proposed that the inactivation of polystyrene macroradicals caused by spin delocalization is the reason that polystyrene photodegradation rates are slower than those of polypropylene. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1070–1076, 2003 相似文献
142.
143.
Ablikim M Achasov MN An L An Q An ZH Bai JZ Baldini R Ban Y Becker J Berger N Bertani M Bian JM Bondarenko O Boyko I Briere RA Bytev V Cai X Cao GF Cao XX Chang JF Chelkov G Chen G Chen HS Chen JC Chen ML Chen SJ Chen Y Chen YB Cheng HP Chu YP Cronin-Hennessy D Dai HL Dai JP Dedovich D Deng ZY Denysenko I Destefanis M Ding Y Dong LY Dong MY Du SX Duan MY Fan RR Fang J Fang SS Feng CQ Fu CD Fu JL Gao Y Geng C Goetzen K Gong WX Greco M Grishin S Gu MH Gu YT Guan YH Guo AQ Guo LB Guo YP Hao XQ 《Physical review letters》2011,107(9):092001
Using (106±4)×10?? ψ(3686) events accumulated with the BESIII detector at the BEPCII e?e? collider, we present the first measurement of decays of χ(c1) to vector meson pairs φφ, ωω, and ωφ. The branching fractions are measured to be (4.4±0.3±0.5)×10??, (6.0±0.3±0.7)×10??, and (2.2±0.6±0.2)×10??, for χ(c1)→φφ, ωω, and ωφ, respectively, which indicates that the hadron helicity selection rule is significantly violated in χ(cJ) decays. In addition, the measurement of χ(cJ)→ωφ provides the first indication of the rate of doubly OZI-suppressed χ(cJ) decay. Finally, we present improved measurements for the branching fractions of χ(c0) and χ(c2) to vector meson pairs. 相似文献
144.
Jian Ying Chen Jeanette RebelloVladimir Vashook Dmytro M. TrotsShao Rong Wang Ting Lian WenJens Zosel Ulrich Guth 《Solid State Ionics》2011,192(1):424-430
Thermal stability, oxygen non-stoichiometry and electrical conductivity of LaNi0.6Fe0.4O3−δ were investigated in the temperature region of 20-1000 °C in Ar/O2 gas flows at oxygen partial pressures between 0.5 and 21,000 Pa. Diffusion mobility was measured in Ar/O2 gas flow at pO2 = 18 Pa. Crystal structure of this compound was found to be stable at the mentioned experimental conditions. LaNi0.6Fe0.4O3−δ is a p-type semiconductor with metallic type conductivity above 150 °C at the investigated pO2 range. Two different (fast and slow) oxygen exchange areas on the temperature-pO2 diagram were established, which are due to two different oxygen anion positions in the double B-site mixed perovskite structure. Oxygen non-stoichiometry in the fast oxygen exchange region reaches about 0.005 of oxygen atomic index. Chemical diffusion and oxygen surface exchange coefficients do not vary at 600-800 °C, but show visible increase above 800-850 °C. 相似文献
145.
This article deals with the determination of multidomain configurations in ferroics taking into account the elastic compatibility of the neighbouring domains. The proposed method is based on transformation matrices, which describe the spacial relationship of two crystal lattice bases for coherent domain pairs. The matrices are calculated using the symmetry operations between domains and lattice parameters. The principle point of this method is the comparison of the product of transformation matrices and the unity matrix. For example, by using this method it was shown that the junction of three and five orientation domains is strained whereas the encounter of four domains is strain free in three different ferroelastic perovskite phases. The derived allowed four-domain configurations are confirmed by experimental data. 相似文献
146.
Dr. Brigita Vigante Karolis Leitonas Dr. Dmytro Volyniuk Dr. Viktorija Andruleviciene Dr. Jurate Simokaitiene Anna Ivanova Dr. Audrius Bucinskas Prof. Juozas V. Grazulevicius Dr. Pavel Arsenyan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(13):3325-3336
With the aim of developing all-organic bipolar semiconductors with high charge mobility and efficient E-type fluorescence (so-called TADF) as environmentally friendly light-emitting materials for optoelectronic applications, four noble metals-free dyes with linear and V-shapes were designed using accepting pyridine-3,5-dicarbonitrile and donating carbazole units. By exploiting a donor-acceptor design strategy and using moieties with different donating and accepting abilities, TADF emitters with a wide variety of molecular weights were synthesized to achieve the optimum combination of charge-transporting and fluorescent properties in one TADF molecule. Depending on molecule structures, different TADF emitters capable of emitting in the range from 453 to 550 nm with photoluminescence quantum yields up to 98 % for the solutions in oxygen-free toluene were obtained. All compounds showed bipolar charge-transport. Hole mobility of 2.8×10−3 cm2/Vs at 7×105 V cm−1 was observed for the compound containing two di-tert-butyl-substituted carbazole moieties. The compounds were tested in both non-doped and doped organic light-emitting diodes using different hosts. It was shown that the developed TADF emitters are suitable for different color devices with electroluminescence ranging from blue to yellow and with brightness, maximum current and external quantum efficiencies exceeding 10 000 cd m−2, 15 cd/A, and 7 %, respectively. 相似文献
147.
148.
Dr. Daniel Bůžek Dr. Karel Škoch Soňa Ondrušová Dr. Matouš Kloda Dr. Dmytro Bavol Andrii Mahun Dr. Libor Kobera Dr. Kamil Lang Dr. Michael G. S. Londesborough Dr. Jan Demel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(67):e202201885
The unprecedented co-thermolysis of decaborane(14) (nido-B10H14) and toluene results in a novel porous material (that we have named “activated borane”) containing micropores between 1.0 and 1.5 nm in diameter and a specific surface area of 774 m2 g−1 (Ar, 87 K) that is thermally stable up to 1000 °C. Solid state 1H, 11B and 13C MAS NMR, UV-vis and IR spectroscopies suggest an amorphous structure of borane clusters interconnected by toluene moieties in a ratio of about three toluene molecules for every borane cluster. In addition, the structure contains Lewis-acidic tri-coordinated boron sites giving it some unique properties. Activated borane displays high sorption capacity for pollutants such as sulfamethoxazole, tramadol, diclofenac and bisphenol A that exceed the capacity of commercially-available activated carbon. The consistency in properties for each batch made, and the ease of its synthesis, make activated borane a promising porous material worthy of broad attention. 相似文献
149.
Mykhailo D. Bilokin’ Volodymyr V. Shvadchak Dmytro A. Yushchenko Guy Duportail Yves Mély Vasyl G. Pivovarenko 《Journal of fluorescence》2009,19(3):545-553
3-Hydroxyquinolones (3HQs) are a new class of water soluble dual fluorescence probes that can monitor both polarity and basicity
(H-bond accepting ability) parameters. Both parameters play an important role in proteins and lipid membranes. Nevertheless,
no method exists actually to measure the basicity parameter separately from the polarity. To achieve this aim, we synthesized
2-benzofuryl-3-hydroxy-4(1H)-quinolone (3HQ-Bf) and characterized its photophysical properties by UV, steady-state and time-resolved
fluorescence spectroscopy. Due to its extended conjugation and totally planar conformation, 3HQ-Bf is characterized by a high
fluorescence quantum yield. In solution, this dye shows an excited state intramolecular proton transfer (ESIPT) reaction resulting
in two tautomer bands in the emission spectra. The ESIPT reaction can be considered as irreversible and is governed by rate
constants from 0.6 to 8 × 109 s−1, depending on the solvent. The analysis of the spectral properties of 3HQ-Bf in a series of organic solvents revealed a marginal
sensitivity to the solvent polarity, but an exquisite sensitivity to solvent basicity, as shown by the linear dependence of
the logarithm of the emission bands intensity ratio, log(IN*/IT*), as well as the absorption or emission maxima wavenumbers as a function of the solvent basicity parameter. This probe may
find useful applications through coupling to a protein ligand, for characterizing the H-bond acceptor ability at the ligand
binding site as well as for studying the basicity changes of lipid membranes during their chemo- and thermotropic conversions. 相似文献
150.
Dmytro I. Danylchuk Seonah Moon Ke Xu Andrey S. Klymchenko 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(42):15062-15066
Visualization of the nanoscale organization of cell membranes remains challenging because of the lack of appropriate fluorescent probes. Herein, we introduce a new design concept for super‐resolution microscopy probes that combines specific membrane targeting, on/off switching, and environment sensing functions. A functionalization strategy for solvatochromic dye Nile Red that improves its photostability is presented. The dye is grafted to a newly developed membrane‐targeting moiety composed of a sulfonate group and an alkyl chain of varied lengths. While the long‐chain probe with strong membrane binding, NR12A, is suitable for conventional microscopy, the short‐chain probe NR4A, owing to the reversible binding, enables first nanoscale cartography of the lipid order exclusively at the surface of live cells. The latter probe reveals the presence of nanoscopic protrusions and invaginations of lower lipid order in plasma membranes, suggesting a subtle connection between membrane morphology and lipid organization. 相似文献