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本文综合评述了近年来2-[2-(二环己膦基)苯基]-1-甲基-1H-吲哚(CM-Phos)膦配体及其衍生物在钯催化的交叉偶联反应中的应用, 主要根据不同种类的交叉偶联反应进行系统性分述, 并对该领域的发展前景进行了展望. 相似文献
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In order to assist the interpretation of carbon-13 NMR spectra for molecules sorbed on solid surfaces, a theoretical analysis of resonance shifts was performed which were measured for simple alkenes and arenes in zeolites of type X and Y and on silica gel surfaces. Quantum chemical computations for simple models of adsorption complexes on the basis of CNDO and PCILO methods were combined with resonance shift calculations by means of the Ramsey theory and by employing an empirical formula to find out the most probable structures for the adsorption complexes. 相似文献
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The semiempirical quantum chemical CNDO/2 method is used to calculate models of specific interaction between benzene, toluene, and butene molecules, respectively, and ions or hydroxyls representing active sites of adsorption on zeolitic surfaces. From energy minima of full potential curves the stabilization energies of the surface complexes have been obtained. On the basis of proposed complexes theoretical carbon-13 NMR chemical shifts of adsorbed molecules are calculated. The theoretical results are in rather good agreement with the experimental ones, confirming the conception of surface complexes. Moreover, experimental paramagnetic shifts of surface complexes containing Co2+ ions are tried to interprete in a quite similar way. 相似文献
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利用氧化钕和盐酸为原料制得Nd(phen)2Cl3(三氯二邻菲罗啉合钕),测得其光谱特性并以稀土氧化钕、苯甲酸和邻菲罗啉为原料制得绿色液体激光介质钕离子的配合物——NdB3phen(三苯甲酸—邻菲罗啉合钕).利用飞秒激光器,采用单光束Z-扫描法研究了NdB3phen的三阶非线性光学特性.结果表明:当入射飞秒激光脉冲波长为400 nm,峰值功率密度为2.94×1014 W/m2,脉宽为117 fs时,测得样品NdB3phen的非线性折射率为-2.84×10-18 cm2/W|NdB3phen在开孔条件下呈现反饱和吸收现象,测出双光子吸收系数的值为9.11×10-12 m/W.实验结果表明,NdB3phen的双光子吸收系数和非线性折射率随着光强的增强而增大. 相似文献
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R. A. Smith J. B. Niederl J. H. C. Smith H. W. Milner A. W. C. Menzies F. Pregl Wm. J. Saschek M. Haitinger O. Heimstädt Ida B. Routh D. Kladischtscheff A. Soltys P. Muller G. Klein O. Werner H. Linser W. Jaeger L. Kofler W. Dernbach J. Deininger J. Donau F. Emich M. Malmy H. J. Fuchs G. W. Chapman E. Fränkel M. Gruber F. Feigl P. Krumholz Fr. L. Hahn G. Jaeger W. Herbert H. O. Hohl W. Münster J. Winkelmann A. Martini 《Analytical and bioanalytical chemistry》1934,99(9-10):355-364
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SO 《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2009,26(5):1897-1924
Let be a bounded Lipschitz domain and consider the energy functional with p]1,∞[ over the space of measure preserving maps In this paper we introduce a class of maps referred to as generalised twists and examine them in connection with the Euler–Lagrange equations associated with over . The main result is a surprising discrepancy between even and odd dimensions. Here we show that in even dimensions the latter system of equations admit infinitely many smooth solutions, modulo isometries, amongst such maps. In odd dimensions this number reduces to one. The result relies on a careful analysis of the full versus the restricted Euler–Lagrange equations where a key ingredient is a necessary and sufficient condition for an associated vector field to be a gradient. 相似文献
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