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981.
Shih-Jieh Sun Teh-Chou Chang 《Journal of polymer science. Part A, Polymer chemistry》1993,31(9):2237-2243
Four series of fully aromatic polycarbonates were prepared by using melt polycondensation from various novel phenylene diphenyl dicarbonates: 1,4-phenylenc diphenyl dicarbonate, 1,3-phenylene diphenyl dicarbonate, methyl-1,4-phenylene diphenyl dicarbonate, and chloro-1,4-phenylene diphenyl dicarbonate with various diols—4,4′-biphenyl diol, hydroquinone, 2,7-naphthalene diol and 1,5-naphthalene diol, respectively. The thermotropic liquid crystalline properties of synthesized polycarbonates were investigated by: (1) examination of the melt birefringence and stir opalescence by a polarizing microscope equipped with a heating stage, (2) characterization by a differential scanning calorimeter (DSC), and (3) analysis of the wide angle x-ray diffraction. It was found that the 1,3-phenylene unit is compensated for the nonlinearity of the carbonate group, and polycarbonates which contain this bent shape unit showed excellent wide mesophase transition in this study. © 1993 John Wiley & Sons, Inc. 相似文献
982.
Summary The retention behaviour of chloro-substituted PAHs on several commercial normal bonded phase HPLC columns has been investigated. Chloro-substitution was shown to generally decrease the retention on stationary phases like amino-, diol- and nitrophenylpropyl-modified silica. Dimethylaminosilica exhibited more complex retention characteristics towards chloro-substituted PAHs. On this stationary phase, the position of the chlorine substituents on the aromatic solute seemed to be of greater importance for retention than on the amino-, nitro- and diolsilica. For some chloro-PAHs, the retention was shown to increase with the number of chloro-substitutions, probably due to the large affinity of the electron-rich nitrogen in the stationary phase for the electron deficient -system of the chloro-PAHs. Chloro-substituted PAHs were strongly retarded on the electron donating 2-(1-pyrenyl)-ethylsilica (PYE) stationary phase. However, the molecular shape of the chloro-derivatives had a large influence on retention, which was considerably decreased for some nonplanar chloro-derivatives of chrysene and benz(a)anthracene. A two-dimensional back-flush HPLC method, consisting of a combination of a nitrophenylsilica column and a PYE column of matched lengths, was shown to be useful for clean-up of chloro-substituted PAHs in environmental samples. 相似文献
983.
M. F. Budyka N. V. Biktimirova T. N. Gavrishova 《Chemistry of Heterocyclic Compounds》2007,43(4):454-459
Isomeric azidostyrylquinolines with a 4-azidostyryl group in position 2 or 4 of the quinoline ring have been synthesized.
In the neutral form the azidostyrylquinolines absorb in the near UV but the protonated species absorb in the short wavelength
region of the visible spectrum. In both forms the azides are lightsensitive and decompose under the influence of light with
a quantum yield close to 1.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 555–561, April, 2007. 相似文献
984.
985.
O. I. Artyushin E. V. Sharova I. L. Odinets K. A. Lyssenko D. G. Golovanov T. A. Mastryukova G. A. Pribylova I. G. Tananaev G. V. Myasoedova 《Russian Chemical Bulletin》2006,55(8):1440-1447
A one-pot synthetic route to phosphorylacetic acid N-aryl(alkylaryl)amides, including those containing two phosphorylmethylcarbamoyl moieties attached to the arene framework,
has been developed. The method is based on reactions of amines with the corresponding acid chlorides generated in situ with the use of phosphorus trichloride as a mild chlorinating agent. The compositions and structures of the compounds obtained
and their extraction ability toward AmIII were determined. Suggestions were made about the compositions of the extracted complexes with phosphorylacetic acid N-aryl(alkylaryl)amides.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1387–1394, August, 2006. 相似文献
986.
配体结构对三元混配配合物分子内芳环堆积作用的影响 总被引:5,自引:1,他引:5
用pH电位滴定法测定了含1,10-邻菲咯啉(Phen)和羧酸(CA)配体的三元混配配合物Pd(Phen)(CA)+体系的稳定常数,比较和讨论了各种三元混配物之间的稳定性差异。实验结果表明:在三元混配物Pd(Phen)(PCA)+中(PCA,苯基羧酸)存在分子内芳环堆积作用,堆积程度依赖于苯基和配位的羧酸根之间的亚甲基数目,最适宜堆积的苯基羧酸是2-苯乙酸和3-苯丙酸。 相似文献
987.
T. A. Vaganova P. S. Yuferov L. I. Goryunov E. V. Panteleeva G. E. Sal’nikov L. N. Shchegoleva V. I. Mamatyuk V. D. Shteingarts 《Russian Chemical Bulletin》2006,55(6):976-980
Stable cyanomethylcyclohexadienyl anions generated in two-electron reduction of isomeric tolunitriles by potassium in liquid
ammonia were detected by NMR spectroscopy. The chemical shifts in these anions were obtained from density functional (PBE/3z)
quantum chemical calculations and the electron density distributions for the anions were calculated in the framework of the
NBO approach at the HF/6-31+G* level of theory. The experimental and calculated δC values are in good agreement. Changes in the δC values on going from the starting nitriles to the corresponding anions are linearly related to the calculated π-electron
densities on the pentadienyl ring carbon atoms.
Dedicated to the memory of Academician V. A. Koptyug on the occasion of the 75th anniversary of his birth.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 940–944, June, 2006. 相似文献
988.
在4,4’-(1,4-苯撑)-双-IN-烷(芳)基-2,6-二苯基I吡啶盐及其聚合物的催化下,二苯甲酮和苯乙烯基苯甲酮与中性条件下的锌粉发生双分子还原反应,生成相应的邻二叔醇;而结构类似的环状酮却主要发生单分子还原反应.双吡啶盐及其聚合物的结构和反应介质的极性对还原反应的速度有很大影响。本文对催化反应的机理也进行了讨论。 相似文献
989.
Summary A significant correlation has been found between the retention indices of polycyclic aromatic hydrocarbons on non-polar stationary phases and the average molecular polarizabilities of the molecules separated on these phases. Equations have been derived for the determination of the average molecular polarizabilities, directly from the retention indices. 相似文献
990.
The Cotton—Mouton effect was used for the study of benzoate, phthalate. isophthalate, and terephthalate anions. The additive tensor characteristics of optical polarizability and magnetic susceptibility ellipsoids have been calculated for C(Ar)-COO– and
. The spatial structures of mono- and deprotonated phthalate anions have been discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 874–876, May, 1993. 相似文献