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391.
Magnetoluminescence in a Photostable,Brightly Luminescent Organic Radical in a Rigid Environment
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Shun Kimura Dr. Tetsuro Kusamoto Dr. Shojiro Kimura Ken Kato Prof. Dr. Yoshio Teki Prof. Dr. Hiroshi Nishihara 《Angewandte Chemie (International ed. in English)》2018,57(39):12711-12715
We investigated the emission properties of a photostable luminescent organic radical, (3,5‐dichloro‐4‐pyridyl)bis(2,4,6‐trichlorophenyl)methyl radical (PyBTM), doped into host molecular crystals. The 0.05 wt %‐doped crystals displayed luminescence attributed to a PyBTM monomer with a room‐temperature emission quantum yield of 89 %, which is exceptionally high among organic radicals. The 10 wt %‐doped crystals exhibited both PyBTM monomer and excimer‐centered emission bands, and the intensity ratio of these two bands was modulated drastically by applying a magnetic field of up to 18 T at 4.2 K. This is the first observation of a magnetic field affecting the luminescence of organic radicals, and we also proposed a mechanism for this effect. 相似文献
392.
Tachikawa T Tojo S Fujitsuka M Majima T 《The journal of physical chemistry. B》2005,109(37):17460-17466
The influence of hydroxypropyl-beta-cyclodextrin (HP-beta-CD) on the one-electron oxidation reaction of aromatic sulfides (S) with Br2*- and the decay process of the S radical cation (S*+) was investigated by pulse radiolysis. The dissociation kinetics of S*+ from the CD cavity was examined in terms of the apparent equilibrium constants (Kapp) for the formation and decay processes of S*+. Inhibition of the one-electron oxidation reaction of S by Br2*- was clearly observed in the presence of HP-beta-CD. On the basis of a comparison between the determined Kapp values, it was found that the binding ability of S*+ with HP-beta-CD is much lower than that of S, because of the hydrophobic nature of the cavity. The formation process of the dimer radical cation of 4-(methylthio)phenylmethanol ((MTPM)2*+), which is generated between MTPM(*+) and neutral MTPM in solution, was also inhibited by the addition of HP-beta-CD. 相似文献
393.
394.
Disulfide cross-linked oligonucleotides, which connect two different sequences of DNA strands, have been synthesized and characterized. Two double helices connected by two different cross-linked oligonucleotides can be arranged in both parallel and antiparallel orientations by addition of the specific complementary strands. 相似文献
395.
,-Dimer of dimethylthymine was monomerized by means of a chain reaction upon the selective photoexcitation of phenanthrene in aerated acetonitrile in the presence of -dicyanobenzene. It was found that the dimer forms a CT-complex with O2. 相似文献
396.
Tetsuro Ito Zulfiqar Ali Ibrahim Iliya Miyuki Furusawa Toshiyuki Tanaka Ken‐ichi Nakaya Yoshikazu Takahashi Ryuichi Sawa Jin Murata Dedy Darnaedi Munekazu Iinuma 《Helvetica chimica acta》2005,88(1):23-34
Four new stilbene glucosides, upunosides A ( 1 ), B ( 5 ), C ( 6 ), and D ( 7 ), were isolated from the stem of Upuna borneensis (Dipterocarpaceae) together with the three known glucosides 3, 4 , and 8 . Upunoside A ( 1 ) is the first natural instance of a glucoside of a resveratrol pentamer, and its aglycone has a dibenzo‐fused bicyclo[5.3.0]octadiene and two dihydrobenzofuran moieties. The relative structure of the aglycone was determined by spectral analysis including 1D and 2D NMR experiments. 相似文献
397.
Barnes DM McLaughlin MA Oie T Rasmussen MW Stewart KD Wittenberger SJ 《Organic letters》2002,4(9):1427-1430
[reaction: see text]. A highly diastereoselective coupling reaction between TBSOP (3) and trityl sulfenimine 4 was developed which provided influenza neuraminidase inhibitor intermediate 7 in 80% yield and >99% de after crystallization. The reaction was shown to be reversible with the high diastereoselectivity resulting from a favorable H-bonding interaction in the major diastereomer. 相似文献
398.
Tetsuro Shinada 《Tetrahedron letters》2006,47(12):1945-1947
An efficient synthesis of N-acyl-N′-substituted guanidines by condensation reaction of thiourea and (Me3Si)2NH in the presence of EDCI is described. Various guanidines were synthesized in a simple manner. 相似文献
399.
Kimura T Kawai K Fujitsuka M Majima T 《Chemical communications (Cambridge, England)》2004,(12):1438-1439
The substitution of 2-aminopurine (Ap) for A7 in the human telomeric sequence d[AGGG(TTAGGG)(3)] resulted in a significant increase in the fluorescence intensity of Ap for the conformational change from duplex to quadruplex. 相似文献
400.
Fujitsuka M Samori S Hara M Tojo S Yamashiro S Shinmyozu T Majima T 《The journal of physical chemistry. A》2005,109(16):3531-3534
Formation of radical cation and charge-transfer complex of [3n]cyclophanes (n = 3, 5, 6) was investigated by transient absorption spectroscopy during pulse radiolysis. Radical cations of [3n]cyclophanes showed the charge resonance band around 700 nm which exhibited a blue-shift as the number of trimethylene bridges increased, indicating formation of highly stabilized intramolecular dimer radical cation of [3n]cyclophanes. The absorption peak of the charge-transfer complex with chlorine atom also showed the shift in accord with the oxidation potential of [3n]cyclophanes. 相似文献