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71.
Structural relaxation of molecules on surfaces can be monitored by observing the spectral evolution as increasing amount of thermal energy is made available. Naphthalene forms excimers in the excited state when amorphously prepared, but relaxes to a more ordered state when heated. Substituent groups on the naphthalene can substantially alter the available pathways during the thermally induced structural relaxation, and is reflected in the formation of excimer or trap fluorescence. A general correlation was determined for the naphthalene substitution with methyl, methoxy, and ethyl groups on the 1- and 2-positions with the pathway taken by the molecular adlayer. 相似文献
72.
熔融萘萃取铁(Ⅱ)-4,7-二苯基-1,10-菲啰啉-四苯硼酸盐三元络合物光度法测定铁 总被引:1,自引:0,他引:1
研究了以熔融萘作为萃取剂,以4,7 二苯基 1,10 菲口罗啉作为显色剂,测定天然水中微量铁的分光光度法。在pH4的条件下,铁(Ⅱ)与4,7 二苯基 1,10 菲口罗啉和四苯硼酸盐能够形成红色三元络合物。在熔融萘存在下,此络合物可以迅速萃入熔融萘。将含有络合物的萘冷却、固化、分离,配制成25mL丙酮溶液,对其进行分光光度分析。实验表明,该络合物最大吸收波长为534nm,摩尔吸光系数和桑德尔灵敏度分别为2×104L·mol-1·cm-1和0.0025μg/cm2,铁(Ⅱ)的质量浓度在0~2 0μg/mL的范围内符合比耳定律。大多数常见离子不干扰测定。已应用于天然水中微量铁的测定。 相似文献
73.
An expeditious one-pot synthesis of 2,3-diaryl/2-aryl-3-heteroaryl-1,3-thiazolidin-4-ones and 1-aryl-1H,3H-thiazolo[3,4-a]benzimidazoles have been accomplished by condensing hetero/aromatic amine, 2-mercaptoacetic acid, aromatic aldehyde and 1,2-phenylenediamine, 2-mercaptoacetic acid and aromatic aldehyde, respectively, in ionic liquids, viz, 1-butyl-3-methyl-imidazolium tetrafluoroborate and 1-methoxyethyl-3-methylimidazolium trifluoroacetate. 相似文献
74.
致癌性多环芳烃萘、蒽、芘的分析方法比较 总被引:4,自引:1,他引:3
利用薄层色谱(TLC)、紫外光谱(UV)、反相高效液相色谱(RPHPLC)对多环芳烃(PAHs)萘、蒽、芘的分析方法进行了研究。TLC中使用环己烷:氯仿(5:4,V/V)作为展开剂时,三者的R,值分别为0.78、0.65和0.72;用UV法在溶液中测定了三者的最大吸收波长分别为303、380、338nm;当流动相为甲醇:水(9:1,V/V)时三者在RP—HPLC中的保留时间为4.179、5.190、6.178min,5次重复RSD分别为1.1%、1.8%、0.91%,并用于实际水样中萘、蒽、芘的分析。 相似文献
75.
A simple, facile, efficient and three-components procedure for the synthesis of pyrimido[1,2-a]benzimidazoles and pyrazolo[3,4-b]pyridines utilizing phenylsulfone synthon, under ultrasonic irradiation was developed. 相似文献
76.
K. D. Ambacheu V. G. Pleshakov B. S. Baatkh V. P. Zvolinskii M. D. Kharlamova A. A. Obynochnyi N. S. Prostakov 《Chemistry of Heterocyclic Compounds》2000,36(4):421-428
A series of 2-substituted benzimidazoles was synthesized. These products were consecutively converted into 5-nitro- and 5-amino-2-substituted benzimidazoles.Russian People's Friendship University, 117198 Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 493–500, April, 200. 相似文献
77.
A theoretical and experimental study of the NMR spectra of 4,5,6,7‐tetrafluorobenzazoles with special stress on PCM calculations of chemical shifts 下载免费PDF全文
Ibon Alkorta José Elguero Marta Pérez‐Torralba Concepción López Rosa M. Claramunt 《Magnetic resonance in chemistry : MRC》2015,53(5):353-362
The chemical shifts and several 19F–19F, 13C–19F and 1H–19F spin‐spin coupling constants (SSCSs) of eight 4,5,6,7‐tetraflurobenzazoles (three benzimidazoles, three benzimidazolinones and two indazoles) have been determined. The chemical shifts were discussed using gauge including atomic orbital‐density functional theory calculations taking into account solvent effects (polarizable continuum model) and, for the solid state, hydrogen bonds (clusters up to three molecules). Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
78.
To describe the adsorption of large organic molecules on metal surfaces, to calculate the corresponding diffusion and rotation barriers, the semi-empirical mono-electronic Hamiltonian of the ASED molecular orbital method have been completed to take into account three body interaction terms. The full re-parametrization of this ASED+ version of ASED was determined on the specific case of benzene adsorbed on Cu(1 1 0) and a full transferability assumed for the member of the polyacene series also adsorbed on Cu(1 1 0). The adsorption energies, geometries, diffusion and rotation barriers are very well described by this new semi-empirical technique of calculation opening the way of optimizing larger conjugated molecule on surface for uni-molecular mechanics or electronics. 相似文献
79.
Solid–liquid equilibrium was measured for benzene + cyclohexane, trans-decahydronaphthalene + naphthalene and cis-decahydronaphthalene + naphthalene under the atmospheric pressure in the temperature range from 226.69 to 353.14 K. The apparatus was specially designed in this study, and it was based on a cooling method. The phase diagram with the complete immiscible solids was observed for the three systems, and the eutectic point was found at x2 = 0.2709 and Teu = 232.11 K for benzene + cyclohexane, x2 = 0.9816 and Teu = 241.98 K for trans-decahydronaphthalene + naphthalene, and x3 = 0.9822 and Teu = 225.74 K for cis-decahydronaphthalene + naphthalene, respectively. Hydrogen solubility was also measured for the two pure substances, trans-decahydronaphthalene and cis-decahydronaphthalene, and the three mixtures, trans-decahydronaphthalene + cis-decahydronaphthalene, trans-decahydronaphthalene + naphthalene, and cis-decahydronaphthalene + naphthalene, in the pressure range from 1.702 to 4.473 MPa at 303.15 K. Considering the solid–liquid equilibrium data, mole ratio of trans-decahydronaphthalene:cis-decahydronaphthalene was set to 50:50, and those of trans-decahydronaphthalene + naphthalene, and cis-decahydronaphthalene + naphthalene to 85:15. The hydrogen solubility increased linearly with the pressure following the Henry's law for all systems. The experimental solubility data were correlated or predicted with the Peng–Robinson equation of state [D.Y. Peng, D.B. Robinson, Ind. Eng. Chem. Fundam. 15 (1976) 59–64; R. Stryjek, J.H. Vera, Can. J. Chem. Eng. 64 (1986) 323–333]. 相似文献
80.