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111.
Suzuki–Miyaura coupling catalyzed by palladium nanoparticles biosynthesized using Glycyrrhiza glabra as reducing and stabilyzing agent
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Hojat Veisi Mehdi Adib Rahman Karimi‐Nami Zahra Yasaei Mahnaz Tajik Talieh Sadat Mosavat Saba Hemmati 《应用有机金属化学》2018,32(3)
An unprecedented environmentally friendly method has been developed for the synthesis of palladium nanoparticles supported on Glycyrrhiza glabra. The synthesized nanoparticles were utilized in Suzuki–Miyaura reaction between different aryl halides and aryl bronic acid in aqueous media. This heterogeneous catalyst can be reused and recycled repeatedly more than five times with only slight loss of its initial catalytic efficiency. This reaction carrid out under atmospheric pressure with high efficiency, unique and simple work‐up procedure and excellent yields. 相似文献
112.
ABSTRACT Three sucrose monoalcohols with free hydroxyl groups at C-1', C-6, and C-6' (1, 4, and 6) were prepared selectively and in good yield from 2,3,3',4,4'-penta-O-benzylsucrose. These compounds were oxidized to aldehydes and reacted with stabilized ylide, Ph3P=CHCO2Me to afford appropriate α,β-unsaturated esters 10, 11, and 12. Each olefin was cis-hydroxylated with OsO4/NMO to stereoisomeric diols 13/14, 15/16, and 17/18, configurations of which were assigned by chemical correlation and CD evaluation. Stereoselectivity of the osmylation reaction was surprisingly low (ca 3:2), especially as compared to a similar process performed on simple derivatives of 6,7-unsaturated methyl glycosides for which the ratio of isomeric diols was assigned as 10:1. The osmylation of 11 (derivative homologated by a C2-unit at the glucose part) did not obey Kishi's rule. Horner-Emmons reaction of sucrose aldehyde 7 with a sugar-derived phosphonate 22 afforded α,β-unsaturated derivative 24, homologated by a C7-unit at the glucose end. 相似文献
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Anna Klepacz-Smółka Jadwiga Sójka-Ledakowicz Katarzyna Paździor Stanisław Ledakowicz 《Chemical Papers》2010,64(2):230-236
An anoxic fixed film bioreactor (FFB) with biomass immobilized on activated carbon and an aerobic continuous stirred tank
bioreactor with overflow were applied to degrade concentrate from nanofiltration of real textile effluents containing Reactive
Red 120 (RR-120). The efficiency of color removal was 99 % irrespective of the fraction of nanofiltration concentrate in the
feed. An approximate dye balance based on the assessed adsorption capacity of RR-120 by activated carbon indicated that the
dye was removed by means of adsorption as well as of biological processes. Aromatic amine released from a dye molecule was
fully adsorbed by activated carbon. COD level in the outflow of the system was above that imposed by legislation. Despite
an adjustment of the feed pH to 7 this was constantly increasing up to the value above 9 in both reactors. Neither the nanofiltration
concentrate nor the effluents from the bioreactors affected the growth of Pseudomonas putida used as toxicity indicator. 相似文献
115.
Assist. Prof. Dr. Sumbal Saba Caio R. Dos Santos Bruno R. Zavarise Aline A. S. Naujorks Marcelo S. Franco Alex R. Schneider Marcos R. Scheide Dr. Ricardo F. Affeldt Assoc. Prof. Dr. Jamal Rafique Prof. Dr. Antonio L. Braga 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(20):4461-4466
Herein, a greener approach to the eosin Y-Na2 catalyzed, C(sp2)−H bond azo coupling of imidazoheteroarene with aryl diazonium salts is described, under acid free conditions. This direct photoredox process resulted in the corresponding azo products in good to excellent yields. Besides, this new approach could also be applicable to anilines, which is a poorly reactive substrate by other methods. The main features of this reaction are that it provides high yields and is gram-scalable and applicable to biologically relevant imidazoheteroarenes and -anilines. 相似文献
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The microbial transformations of peucedanin and oreoselon by the fungi Aspergillus niger and Aspergillus sp. were investigated for the first time. Incubation of peucedanin with A. niger yielded a new hydroxylated metabolite with high yield (56%), which was characterized as 2-(1-hydroxypropan-2-yl)-3-methoxy-7H-furo[3,2-g]chromen-7-one. Oreoselon was converted to a new reduced metabolite methyl 3-(2,3-dihydro-6-hydroxy-2-isopropyl-3-oxobenzofuran-5-yl)propanoate in biotransformation by Aspergillus sp. The structures of the metabolites were determined by spectroscopic methods including IR, EI-MS, 1H NMR, 13C NMR, and elemental analysis. 相似文献
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119.
Jadwiga Skubiszewska-Zi?ba 《Applied Surface Science》2010,256(17):5520-5527
VPO catalysts were prepared on oxidized and unoxidized activated carbons differing in initial porous structure. Carbons were oxidized under relatively soft (30% H2O2, 200 °C) and hard (50% H2O2, 350 °C) conditions. Carbon modification was carried out hydrothermally in a traditional autoclave (HTT) or a microwave reactor (MWT). The synthesis was also carried out under hydrothermal (HTS or MWS) conditions. V2O5 and NH4VO3 were used as precursors. The samples are characterized by diversified porous structure at SBET = 732-1617 m2/g and Vpor = 0.44-0.90 cm3/g, as well as various degree of VPO crystallinity. Possibility of preparation of the VPO catalysts under ecologically appropriate conditions, i.e. in aqueous solutions, was shown. 相似文献
120.
Kuta J Patchkovskii S Zgierski MZ Kozlowski PM 《Journal of computational chemistry》2006,27(12):1429-1437
Computational modeling of the enzymatic activity of B12-dependent enzymes requires a detailed understanding of the factors that influence the strength of the Co--C bond and the limits associated with a particular level of theory. To address this issue, a systematic analysis of the electronic and structural properties of coenzyme B12 models has been performed to establish the performance of three different functionals including B3LYP, BP86, and revPBE. In particular the cobalt-carbon bond dissociation energies, axial bond lengths, and selected stretching frequencies have been analyzed in detail. Current analysis shows that widely used B3LYP functional significantly underestimates the strength of the Co--C bond while the nonhybrid BP86 functional produces very consistent results in comparison to experimental data. To explain such different performance of these functionals molecular orbital analysis associated with axial bonds has been performed to show differences in axial bonding provided by hybrid and nonhybrid functionals. 相似文献