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31.
32.
Dechlorination of the tetrachlorocyclopentadienone dimer and perchloro-7-oxotricyclo[6.1.0.04,8]nona-2,5-diene-9-carboxylic acid N,N-diethylamide with hydride ion donors (NaBH4, LiAlH4, etc.) and electron donors (CrCl2 or Zn) were studied. The possible pathways of unusual transformations of both sterically hindered molecules are considered.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1001–1007, June, 2006. 相似文献
33.
Summary TheLIS data of 5-(3-N,N-dimethylaminopropyl)-5H-dibenzo[a,d]cycloheptene (1), 5-(3-N,N-dimethyl-and 5-(3-N-methylaminopropylidene)-10,11-dihydro-5H-dibenzo[a,d]-cycloheptene (2,2a) and 5-(3-N,N-dimethylaminopropyl)-10,11-dihydro-5H-dibenzo[a,d]cycloheptene (3) were used to calculate populations of possible conformers in solution. The substrate geometries of the particular conformers were taken from force field calculations. ALIS simulation program was used which is able to handle up to four possible conformations. The limits and special features of the method for highly flexible structures — especially for the case that the coordinating group is within a flexible chain — are discussed.
Konformationsanalyse von 5-H-Dibenzo[a,d]cyclohepten-Derivaten mit flexiblen aminosubstituierten Seitenketten mittels Lanthaniden-induzierter Verschiebungen. Konformationsanalyse hochflexibler Strukturen, 3. Mitt.
Zusammenfassung DieLIS-Werte von 5-(3-N,N-Dimethylaminopropyl)-5H-dibenzo[a,d]-cyclohepten (1), 5-(3-N,N-Dimethyl- bzw. 5-(3-N-Methylaminopropyliden)-10,11-dihydro-5H-dibenzo[a,d]-cyclohepten (2 bzw.2a) und 5-(3-N,N-Dimethylaminopropyl)-10,11-dihydro-5H-dibenzo[a,d]cyclohepten (3) wurden zur Berechnung von Populationen bevorzugter Konformerer herangezogen. Die Geometrien der einzelnen Konformeren wurden aus Force-Field-Rechnungen entnommen. Es wurde einLIS-Programm verwendet, das bei der Simulation bis zu vier Konformationen berücksichtigen kann. Die Grenzen der Anwendbarkeit der Methode — insbesondere die speziellen Probleme die auftreten, wenn die Koordinationsstelle innerhalb einer flexiblen Kette liegt — werden diskutiert.相似文献
34.
A previously unknown recyclization of an 11-acyldipyrido[1,2-a:1,2-c]imidazolium cation to 8-formyl-9-methyl(aryl)pyrido[1,2-a]benzimidazoles has been discovered. The proposed reaction mechanism includes a selective opening of one of the pyridinium rings and the formation of a benzaldehyde fragment via condensation of the intermediate with the participation of the acyl group.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 135–139, January, 2005. 相似文献
35.
The title compound is orthorhombic witha = 26·132(6),b = 11·023(2),c = 8·317(5), ?; space group Iba2;Z = 8,D
m
= 1·21(1),D
c
= 1·192 Mg m−3, 1/2(H2O) per molecule in asymmetric unit; λ (MoKα) = 0·7107A; μ = 0·46 cm−1; F(000) = 936. The structure was solved by direct methods and refined to R(F) value of 0·069 using 327 reflections withF ≥ 5σ(F) out of 727 independent reflections for2τ max = 46°. Thetrans fused cyclohexane and cyclohexanone rings form layers along thea-b plane. The axial methyl attached at the bridge-head, interlocks with the translated methylene of the cyclobutane fused across
the cyclohexane ring. The equatorial hydroxyl at the bridge-head adjacent to the methyl junction and the water molecule on
the two-fold form a water bridge along thez axis. The packing is reminiscent of that observed for the cholesterols used in membrane structure studies. 相似文献
36.
Determination of three antidepressants in urine using simultaneous derivatization and temperature‐assisted dispersive liquid–liquid microextraction followed by gas chromatography–flame ionization detection 下载免费PDF全文
Ali Akbar Alizadeh Nabil Nina Nouri Mir Ali Farajzadeh 《Biomedical chromatography : BMC》2015,29(7):1094-1102
This paper presents a fast and simple method for the extraction, preconcentration and determination of fluvoxamine, nortriptyline and maprotiline in urine using simultaneous derivatization and temperature‐assisted dispersive liquid–liquid microextraction (TA‐DLLME) followed by gas chromatography–flame ionization detection (GC‐FID). An appropriate mixture of dimethylformamide (disperser solvent), 1,1,2,2‐tetrachloroethane (extraction solvent) and acetic anhydride (derivatization agent) was rapidly injected into the heated sample. Then the solution was cooled to room temperature and cloudy solution formed was centrifuged. Finally a portion of the sedimented phase was injected into the GC‐FID. The effect of several factors affecting the performance of the method, including the selection of suitable extraction and disperser solvents and their volumes, volume of derivatization agent, temperature, salt addition, pH and centrifugation time and speed were investigated and optimized. Figures of merit of the proposed method, such as linearity (r2 > 0.993), enrichment factors (820–1070), limits of detection (2–4 ng mL?1) and quantification (8–12 ng mL?1), and relative standard deviations (3–6%) for both intraday and interday precisions (concentration = 50 ng mL?1) were satisfactory for determination of the selected antidepressants. Finally the method was successfully applied to determine the target pharmaceuticals in urine. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
37.
综述了凤尾蕨科植物中分离得到的1H 茚 1 酮类倍半萜的化学合成、化学转化、生物活性以及1 茚酮倍半萜的二聚体化合物和三环1 茚 1 酮倍半萜等方面的研究情况. 相似文献
38.
Heck and domino‐Heck reactions of unsaturated N‐acylamino‐substituted tricyclic imides with aryl(heteroaryl) iodides and phenyl‐ or (trimethylsilyl)acetylene were either carried out in the presence of formate or phenyl‐ and (trimethylsilyl)acetylene, respectively. The C? C coupling reactions appeared to be completely diastereoselective, giving the corresponding N‐acylamino‐5‐exo‐aryl (heteroaryl)‐ ( 5a – c, 6a , b ), N‐(benzoylamino)‐5‐exo‐phenyl‐6‐exo‐[(trimethylsilyl)ethynyl]‐ ( 5d ), or 5‐exo‐(4‐chlorophenyl)‐N‐(2,2‐dimethylpropanoylamino)‐6‐exo‐(phenylethynyl)bicyclo[2.2.1]heptane‐2‐endo,3‐endo‐dicarboximide ( 6c ) (Schemes 3 and 4). 相似文献
39.
A simple, rapid and sensitive HPLC method was developed and validated for the determination of four tricyclic antidepressants (TCAs): amitriptyline, doxepin, clomipramine (CLO) and imipramine, in pharmaceutical formulations and biological fluids. A Kromasil C(8 )analytical column (250 x 4 mm, 5 microm) was used for the separation, with a mobile phase consisting of 0.05 M CH(3)COONH(4) and CH(3)CN (45:55 v/v) delivered at 1.5 mL/min isocratically. Quantification was performed at 238 nm, with bromazepam (1.5 ng/microL) as the internal standard. The determination of TCAs in blood plasma was performed after protein precipitation. Urine analysis was performed by means of SPE using Lichrolut RP-18 Merck cartridges providing high absolute recoveries (> 94%). Direct analysis of urine was also performed after two-fold dilution. The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability and sensitivity. Repeatability (n = 5) and between-day precision (n = 5) revealed RSD <13%. Recoveries from biological samples ranged from 91.0 to 114.0%. The absolute detection limit of the method was calculated as 0.1-0.6 ng in blood plasma and 0.2-0.5 ng in extracted urine or 0.4-0.7 in diluted urine. The method was applied to real samples of plasma from a patient under CLO treatment. 相似文献
40.
Mohabat Taghizadeh Mahmoud Ebrahimi Ebrahim Fooladi Mehdi Yoosefian 《Journal of separation science》2022,45(8):1434-1444
A sensitive and straightforward liquid–liquid–liquid microextraction method was developed to preconcentrate and cleanup antidepressants, including mirtazapine, venlafaxine, escitalopram, fluoxetine, and fluvoxamine, from biological samples before analyzing with high-performance liquid chromatography. The essential novelty of this study is using magnetic ionic liquids as the extraction phase in the lumen of hollow fiber and preparing a liquid magnetic stir bar. In this method, polypropylene hollow fiber was utilized as the permeable membrane for the analyte extraction. Six magnetic ionic liquids consisting of the transition metal and rare earth compounds were synthesized and then hollow fiber lumen was injected as acceptor phase to extract the antidepressants. Besides, 3-pentanol as a water-immiscible solvent was impregnated in the hollow fiber wall pores. The effective factors in the method were optimized with the central composition design. The resultant calibration curves were linear over the concentration range of 0.8–400.0 ng mL−1 (R2 ≥ 0.996). The method displayed the proper detection limit (0.11–0.24 ng mL−1), the reasonable limit of quantification (≤0.79 ng mL−1), wide linear ranges, high preconcentration factors (≥294.3), and suitable relative standard deviation (2.31–5.47%) for measuring antidepressant medications. Analysis of human milk and urine samples showed acceptable recoveries of 96.5–103.8% with excellent relative standard deviations lower than 5.95%. 相似文献