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41.
Hiroshi Maruoka Kenji Yamagata Fumi Okabe Yukihiko Tomioka 《Journal of heterocyclic chemistry》2006,43(4):859-865
The unusual formation of 1‐acyl‐1,2‐dihydro‐3H‐pyrazol‐3‐ones starting from 3‐acyloxypyrazoles by Fries‐type rearrangement is described. Under normal conditions, acylation of 2,4‐dihydro‐3H‐pyrazol‐3‐ones 1 and 2 with acid chlorides or anhydrides in the presence of triethylamine gave the corresponding 3‐acyloxypyrazoles 3a‐f and 4a‐f . Treatment of 3a‐c and 4a‐f with Lewis acid, e.g. titanium(IV) chloride and tin(IV) chloride, caused migration of acyl groups to afford the corresponding 1‐acyl‐1,2‐dihydro‐3H‐pyrazol‐3‐ones 5a‐c and 6a‐f . Interestingly, the reactions of 3‐acyloxypyrazoles 3e and 3f with tin(IV) chloride provided the corresponding tin(IV) complexes 8e and 8f . 相似文献
42.
Sho Nishida Hiroshi Maruoka Yuki Yoshimura Takao Goto Ryoko Tomita Eiichi Masumoto Fumi Okabe Kenji Yamagata Toshihiro Fujioka 《Journal of heterocyclic chemistry》2012,49(2):303-309
As a part of systematic investigation of synthesis and biologically active compounds of thiazolidine (TZD) derivatives containing pyrazole ring system, several new pyrazole–TZD derivatives 8a , 8b , 8c , 8d and 9a , 9b , 9c , 9d have been synthesized. Compounds 8a , 8b , 8c , 8d were prepared from N‐substituted TZDs 6a , 6b , 6c , 6d and 1H‐pyrazole‐4‐carboxaldehyde 7 by Knoevenagel‐type reaction. Treatment of 8a , 8b , 8c , 8d with sodium hydride at room temperature caused dimerization reaction to afford the corresponding spirocompounds 9a , 9b , 9c , 9d . All the synthesized compounds were characterized by spectroscopic analysis. In vitro, the synthesized compounds 8a , 8b , 8c , 8d and 9a , 9b , 9c , 9d were tested for their growth inhibitory activity in A549 lung cancer, B16F10 murine melanoma, and HeLa human uterine carcinoma cells and for their differentiation of 3T3‐L1 preadipocytes to adipocytes. The results showed that compound 8c possessed growth inhibitory effect of B16F10 cells (IC50 = 27 μM) and compounds 9c , 9d had induction effect on the differentiation of 3T3‐L1 preadipocytes. J. Heterocyclic Chem., (2011). 相似文献
43.
Solutions of suspended particles of nanodiamond and nanosilica in deionized water 25 mg/10 mL were prepared for the purpose of achieving saturation adsorption. The respective saturation thresholds and adsorption reaction constants of lysozyme of extremely diluted concentrations 0–1000 nmol/L in 7 mmol/L (potassium phosphate buffer solution) PPBS on the surfaces of nanodiamond and nanosilica of 100 nm diameter have been measured. The adsorbed quantities of lysozyme on a unit surface area of both nanoparticles can be derived. The possible influences by the adsorption surface profile and adsorption surface area, adsorption ability of the nanoparticles, strength and activity of lysozyme have been discussed. 相似文献
44.
Taniguchi Y Nakamura A Senko Y Nagatsugi F Sasaki S 《The Journal of organic chemistry》2006,71(5):2115-2122
Triplex-forming oligonucleotides (TFOs) are sequence-specific DNA-binding agents, but their target duplexes are limited to homopurine/homopyrimidine sequences because of interruption of the pyrimidines bases in the purine region. This problem has not been fully solved despite a wide variety of studies. Recently, we have developed a bicyclic system as a novel scaffold for nucleoside analogues (WNA, W-shaped nucleoside analogues) and determined two useful compounds, WNA-betaT (2) and WNA-betaC (5), for highly stable and selective triplex formation at a TA and a CG interrupting site, respectively. However, subsequent investigations have shown that the triplex formation using WNA is dependent on the neighboring bases of the TFOs. In this study, we have synthesized new WNA derivatives having halogenated recognition bases or benzene rings and evaluated the effects of the modifications on the triplex stability as well as selectivity. It has been found that the WNA-betaT analogues holding 5-halogenated pyrimidine bases (WNA-beta(Br)U (3) and WNA-beta(F)U (4)) exhibit high CG-selectivity. On the other hand, the WNA-betaT derivatives having the bromo-substituted benzene ring (mBr-WNA-betaT (10) and oBr-WNA-betaT (11)) have shown high selectivity to a TA interrupting site with high stability in the sequences to which the original WNA-betaT do not bind. Thus, sequence-dependency has been overcome by the sequence-dependent use of WNA-betaT, mBr-WNA-betaT, and oBr-WNA-betaT. 相似文献
45.
[structure: see text] The chiral recognition ability of enantiopure O-methyl, O-ethyl, O-propyl, and O-phenyl phenylphosphonothioic acids (1a-d) for various kinds of racemic amines during salt crystallization and the chiral recognition mechanism were thoroughly investigated. The chiral recognition abilities of enantiopure 1a-d for a wide variety of racemic amines varied in a range of 6 to >99% enantiomeric selectivity. Deposited less-soluble diastereomeric salts were classified into two categories, prism- and needle-type crystals; the prism-type crystals were composed of a globular molecular cluster, while there existed a 2(1) column in the needle-type crystals. In contrast to a general observation of a similar 2(1) column in the less-soluble diastereomeric salt crystals of chiral primary amines with chiral carboxylic acids, the globular molecular cluster is a very unique hydrogen-bonding motif that has never been constructed in diastereomeric salt crystals. Excellent chiral recognition was always achieved when the less-soluble diastereomeric salts were prism-type crystals. Significant correlations were found between the degree of the chiral recognition with 1a-d, the crystal shape of the less-soluble diastereomeric salts, and the hydrogen-bonding motif (molecular cluster/2(1) column). The chiral recognition mechanisms via the molecular cluster and the 2(1) column formations are discussed in detail on the basis of X-ray crystallographic analyses. 相似文献
46.
The reactions of 2‐amino‐4,5‐dihydro‐3‐furancarboxarnides 1a,b with cyanomethylene compounds (such as alkyl cyanoacetates and malononitrile) gave the corresponding ring‐opened products 2a‐f. Compounds 2a‐d reacted with methanesulfonic acid to give the corresponding α‐alkylidene‐γ‐butyrolactones 3a‐d. On the other hand, treatment of 2e,f with methanesulfonic acid yielded 3‐pyridinecarbonitrile derivatives 4a,b. 相似文献
47.
Vladimir Y. Torbeev Erik Fumi Marc‐Olivier Ebert W. Bernd Schweizer Donald Hilvert 《Helvetica chimica acta》2012,95(12):2411-2420
α‐Methyl‐L ‐proline is an α‐substituted analog of proline that has been previously employed to constrain prolyl peptide bonds in a trans conformation. Here, we revisit the cis‐trans prolyl peptide bond equilibrium in derivatives of α‐methyl‐L ‐proline, such as N‐Boc‐protected α‐methyl‐L ‐proline and the hexapeptide H‐Ala‐Tyr‐αMePro‐Tyr‐Asp‐Val‐OH. In Boc‐α‐methyl‐L ‐proline, we found that both cis and trans conformers were populated, whereas, in the short peptide, only the trans conformer was detected. The energy barrier for the cis‐trans isomerization in Boc‐α‐methyl‐L ‐proline was determined by line‐shape analysis of NMR spectra obtained at different temperatures and found to be 1.24 kcal/mol (at 298 K) higher than the corresponding value for Boc‐L ‐proline. These findings further illuminate the conformationally constraining properties of α‐methyl‐L ‐proline. 相似文献
48.
Kaoru Nakajima Yuki Komai Eriko Watanabe Fumi Moritsuka Shimako Anzai Kashiko Kodate 《Optical Review》2007,14(4):201-207
We designed and developed a volume phase holographic (VPH) grism with high resolution and high efficiency in the near-infrared
light domain (1550 nm) to be applied as a wavelength de-multiplexing device of a photonic network. In order to achieve both
diffraction efficiency of over 80% and wavelength resolution of 0.08 nm, we newly designed and fabricated a VPH grism with
high efficiency and high wavelength resolution in near-infrared wavelength region by sandwiching a VPH grating between prisms.
An active feedback control technique was introduced to a two-beam interference exposure system, and we also applied it to
a wavelength de-multiplexing device for a photonic network. Consequently, a VPH grism was successfully fabricated with diffraction
efficiency of over 80% by employing the Bragg condition of 1550 nm at the incident wavelength from 1530 to 1570 nm, and high
refractive index modulation of 0.047 was confirmed. 相似文献
49.
50.
Synthetic oligonucleotides (ONs) are valuable tools that interfere with gene expression by specifically binding to target genes in a sequence-specific manner. Reactive ONs containing cross-linking agents are expected to induce efficient inhibition because they bind covalently to target genes. In recent years, researchers have reported several cross-linking reactions that target DNA induced by external stimuli. This short review highlights recently developed novel cross-linking reactions, focusing particularly on nucleoside derivatives developed by our group. 相似文献