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排序方式: 共有283条查询结果,搜索用时 31 毫秒
201.
Christian Kleeberg Dr. Li Dang Zhenyang Lin Prof. Dr. Todd B. Marder Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(29):5350-5354
A simple but effective copper‐catalyzed borylation of aryl halides, including electron‐rich and sterically hindered aryl bromides, with alkoxy diboron reagents occurs under mild conditions (see scheme). Preliminary DFT studies of the mechanism suggest that σ‐bond metathesis between a copper–boryl intermediate and the aryl halide generates the aryl boronate product.
202.
Zhou W Kuebler SM Carrig D Perry JW Marder SR 《Journal of the American Chemical Society》2002,124(9):1897-1901
New triarylamine dialkylsulfonium salts that are photosensitive in the near-ultraviolet have been prepared. The quantum yields of photoacid generation were found to be approximately 0.5 and are independent of the counterion. On the other hand, the efficiencies of the sulfonium salts toward the photopolymerization of cyclohexene oxide depend on the counterion and the sulfonium substituents. Photopolymerization kinetic studies demonstrate that these triphenylamine sulfonium salts are highly efficient cationic photoinitiators. 相似文献
203.
Jacquelyn M. BurkeR. Benjamin Coapes Andrés E. GoetaJudith A.K. Howard Todd B. Marder Edward G. RobinsStephen A. Westcott 《Journal of organometallic chemistry》2002,649(2):199-203
The compound [Rh(COE)2(acac)] (1) is a catalyst precursor in its own right, and a starting material for the preparation of other catalyst precursors for use in a variety of reactions such as hydroboration, diboration and the addition of arylboronic acids to aldehydes. Although a preparation using Tl(acac) and [Rh(COE)2(μ-Cl)]2 is in the literature, it would appear that it is not widely known and we have received several requests for our synthetic protocol for 1, which does not use any thallium salts. We present herein a synthesis of 1 from [Rh(COE)2(μ-Cl)]2 and Na(acac), along with its full spectroscopic and structural characterisation. The single crystal X-ray structure of 1 indicates approximate square-planar geometry at Rh, with the two olefinic CC bonds lying perpendicular to the square plane. 相似文献
204.
Risko C Barlow S Coropceanu V Halik M Brédas JL Marder SR 《Chemical communications (Cambridge, England)》2003,(2):194-195
The reduction of a phenylene-bridged bis(dioxaborine) affords a strongly delocalised organic mixed-valence system; for the first time details of the vibrations coupled to the electron transfer have been extracted from the intervalence band. 相似文献
205.
Bell NJ Cox AJ Cameron NR Evans JS Marder TB Duin MA Elsevier CJ Baucherel X Tulloch AA Tooze RP 《Chemical communications (Cambridge, England)》2004,(16):1854-1855
Bis-pinacolatodiboron reacts with [small alpha],[small beta]-unsaturated carbonyl compounds to give 1,4- and unprecedented 3,4-additions in the presence of a second generation Pt(0) catalyst at ambient temperature. 相似文献
206.
207.
Kwon O Barlow S Odom SA Beverina L Thompson NJ Zojer E Brédas JL Marder SR 《The journal of physical chemistry. A》2005,109(41):9346-9352
The electron-donor abilities of ten aminophenyl systems and an additional aminothienyl system are compared using density functional theory calculations. The systems studied here include those with amine nitrogen atoms bearing alkyl or aryl groups and those with amine nitrogen atoms as part of a heterocycle. Their abilities to act as donors in electron-transfer processes are assessed from calculated vertical ionization potentials for the aminobenzenes, which are in good agreement with available experimental data. Their abilities to act as intramolecular pi-electron donors in conjugated systems are inferred from the bond lengths and charge densities calculated for the corresponding 4-aminobenzaldehydes and 4-aminobenzonitriles. The computed (13)C NMR chemical shifts for the 4-aminobenzaldehydes and 4-aminobenzonitriles are in good agreement with published and new experimental data. The chemical shifts correlate well with the computed charge densities and can, to some extent, be used as an experimental probe of pi-donor strength. We find that the electron-transfer-donor strengths do not correlate well with pi-donor strengths: these differences can largely be attributed to steric effects. 相似文献
208.
Zhang Q Prins P Jones SC Barlow S Kondo T An Z Siebbeles LD Marder SR 《Organic letters》2005,7(22):5019-5022
[structure: see text] The first fluorine-substituted hexabenzocoronene has been synthesized and is much more readily reduced than its nonfluorinated analogues. Thin films of this material show columnar order at room temperature, and the charge-carrier mobility measured by the pulse-radiolysis time-resolved microwave conductivity technique is comparable to that of other hexabenzocoronene materials. 相似文献
209.
Blanche PA Kippelen B Schülzgen A Fuentes-Hernandez C Ramos-Ortiz G Wang JF Hendrickx E Peyghambarian N Marder SR 《Optics letters》2002,27(1):19-21
We demonstrate the recording of holograms and their nondestructive readout in a photorefractive polymer, using two-photon absorption. Sensitivity is provided by the excitation of the electroactive chromophore with femtosecond pulses, followed by charge injection into the photoconducting poly(N -vinylcarbazole) matrix. The holograms can be fully erased with a pulsed laser source but are insensitive to cw laser beams with the same wavelength. Studies of the field and intensity dependence of the diffraction efficiency indicate that the holograms are formed through the photorefractive effect. 相似文献
210.
Hilmar Reiss Dr. Lei Ji Jie Han Silke Koser Olena Tverskoy Dr. Jan Freudenberg Dr. Felix Hinkel Michael Moos Dr. Alexandra Friedrich Dr. Ivo Krummenacher Prof. Christoph Lambert Prof. Holger Braunschweig Prof. Andreas Dreuw Prof. Todd B. Marder Prof. Uwe H. F. Bunz 《Angewandte Chemie (International ed. in English)》2018,57(30):9543-9547
A cyclocondensation of TIPS‐ethynyl‐substituted diaminoarenes with in situ obtained 4,5‐dibromocyclohexa‐3,5‐diene‐1,2‐dione has led to the synthesis of tetrabromotetraazapentacene (BrTAP). BrTAP is easily reduced to its air‐stable radical anion and electron mobilities >0.56 cm2 V?1 s?1 can be achieved in thin‐film transistors. 相似文献