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171.
Fustero S Rodríguez E Herrera L Asensio A Maestro MA Barrio P 《Organic letters》2011,13(24):6564-6567
Aromatic tert-butylsulfinyl ketimines bearing a suitable Michael acceptor at the ortho position readily undergo an intramolecular conjugate addition achieving indanone derivatives in good yields and complete diastereoselectivity. 相似文献
172.
Petr Vinš Martina Vermachová Pavel Drašar Melisa del Barrio Carmen Jarne Vicente L. Cebolla Abel de Cózar Ronen Zangi Fernando P. Cossío 《Tetrahedron》2013
Different generations of dendrimers incorporating one fluorescent core of apigenin and three Fréchet benzylic dendrons have been prepared. The chief geometric features of these dendrimers have been obtained by Molecular Dynamics simulations. These computational data suggest that the asphericities of dendrimers belonging to the third and fourth generations are considerably larger than those associated with lower radii of gyration. Fluorescence spectra of high generation dendrimers evolve along time and quantum yields show an appreciable lowering for the fourth generation dendrimer. All these data suggest aggregation phenomena and lower quantum yields for nonspheric dendrimers in solution. 相似文献
173.
N. Satyamurthy G. T. Blda H. C. Padgett J. R. Barrio 《Journal of carbohydrate chemistry》2013,32(4):489-512
Electrophilic syn additions of fluorine and acetylhypofluorite across double bonds in 3,4,6-tri-0-acetyl-D-glucal (1a) and D-glucal (1b) followed by acid hydrolysis gave mixtures of 2-deoxy-2-fluoro-D-glucose (8) and 2-deoxy-2-fluoro-D-mannose (9). These addition reactions were conducted in various solvents with a view to investigating the reaction mechanism based on the product distribution analysis by 19F NMR. Tight ion pair intermediates (4 and 5) have been invoked to explain the stereospecific characteristics of the addition of fluorine or acetylhypofluorite to glycals. The relative stabilities of these intermediates control the product distributions and are governed by a) the anomeric effect (axial vs equatorial preference of C(1) electronegative substituents in pyranose rings), b) dipole-dipole interactions of the lone pairs of electrons on the ring oxygen and the electronegative substituents on C(2), and c) the gauche relationship that exists between the C(2) fluorine and polar groups in the molecule. The overall contribution of these three factors largely depends upon the polarity of the solvent. A rationale for the 19F NMR chemical shifts as well as the anomeric distributions of the α and β anomers of 2-FDG (8) and 2-FDM (9) has been proposed. 相似文献
174.
Prof. Dr. Santos Fustero Lidia Herrera Ruben Lázaro Elsa Rodríguez Dr. Miguel A. Maestro Dr. Natalia Mateu Pablo Barrio 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(35):11776-11785
The nucleophilic addition (AN) / intramolecular aza‐Michael reaction (IMAMR) process on Ellman’s tert‐butylsulfinyl imines, bearing a Michael acceptor in the ortho position, is studied. This reaction affords 1,3‐disubstituted isoindolines with a wide range of substituents in good yields and diastereoselectivities. Interestingly, careful choice of the base for the aza‐Michael step allows either the cis or the trans diastereoisomers to be exclusively obtained. This stereodivergent cyclization has enabled the synthesis of C2‐symmetric bisacetate‐substituted isoindolines. In addition, bisacetate isoindolines bearing two well‐differentiated ester moieties are also noteworthy because they may allow for the orthogonal synthesis of β,β′‐dipeptides using a single nitrogen atom as a linchpin. 相似文献
175.
Daniel Mouzo Raquel Rodríguez-Vzquez Carlos Barrio Lucio García Carlos Zapata 《Molecules (Basel, Switzerland)》2022,27(19)
The control of the duration of the dormancy phase is a significant challenge in the potato industry and for seed producers. However, the proteome landscape involved in the regulation of the length of the dormancy period over potato cultivars remains largely unexplored. In this study, we performed for the first time a comparative proteome profiling of potato cultivars with differential duration of tuber dormancy. More specifically, the proteome profiling of Agata, Kennebec and Agria commercial potato varieties with short, medium and medium-long dormancy, respectively, was assessed at the endodormancy stage using high-resolution two-dimensional electrophoresis (2-DE) coupled to reversed-phase liquid chromatography–tandem mass spectrometry (LC-TripleTOF MS/MS). A total of 11 proteins/isoforms with statistically significant differential abundance among cultivars were detected on 2-DE gels and confidently identified by LC-TripleTOF MS/MS. Identified proteins have known functions related to tuber development, sprouting and the oxylipins biosynthesis pathway. Fructokinase, a mitochondrial ADP/ATP carrier, catalase isozyme 2 and heat shock 70 kDa were the proteins with the strongest response to dormancy variations. To the best of our knowledge, this study reports the first candidate proteins underlying variable dormancy length in potato cultivars. 相似文献
176.
Rubén Miguélez Nina Semleit Carlos Rodríguez-Arias Dr. Pavel Mykhailiuk Prof. Dr. José M. González Prof. Dr. Gebhard Haberhauer Dr. Pablo Barrio 《Angewandte Chemie (International ed. in English)》2023,62(26):e202305296
Selective functionalization of non-activated C(sp3)−H bonds is a major challenge in chemistry, so functional groups are often used to enhance reactivity. Here, we present a gold(I)-catalyzed C(sp3)−H activation of 1-bromoalkynes without any sort of electronic, or conformational bias. The reaction proceeds regiospecifically and stereospecifically to the corresponding bromocyclopentene derivatives. The latter can be readily modified, comprising an excellent library of diverse 3D scaffolds for medicinal chemistry. In addition, a mechanistic study has shown that the reaction proceeds via a so far unknown mechanism: a concerted [1,5]-H shift / C−C bond formation involving a gold-stabilized vinylcation-like transition state. 相似文献