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21.
Saadi Bayat Emilia Abd Malek Normi M. Yahaya Abu Bakar Salleh Bimo Ario Tejo Mohd Basyaruddin Abdul Rahman 《Tetrahedron letters》2014
The promiscuous aldo–ketoreductase (AKR) enzyme is used as a sustainable biocatalyst for the first time to catalyze asymmetric aldol reactions in aqueous medium. The reactions between aromatic aldehydes and cyclic/acyclic ketones give the corresponding products in moderate yields and enantioselectivities in the presence of water. The influence of solvents, the mole ratio of substrates, and enzyme concentration are investigated. The mechanism of the AKR1A1-catalyzed aldol reaction is also discussed. 相似文献
22.
Emilia Gîlcă Andrada Măicăneanu Petru Ilea 《Central European Journal of Chemistry》2014,12(8):821-828
The aim of this study was to compare several anion exchangers and to investigate the capacity of Amberlite IRA410 to remove zinc as chloride [ZnCl3]? from hydrochloric solutions (1 M). Influence of the process parameters such as stirring rate, resin quantity and zinc initial concentration over the removal process, was considered. The highest experimental ionic exchange capacity between the considered anionic exchangers, in the same working conditions (500 rpm, 5 g resin and 500 mg L?1), was obtained for Amberlite IRA410, 8.34 mg g?1. With an increase of zinc ions concentration, ionic exchange capacity increased up to 19.31 mg g?1 (1100 mg L?1). The experimental data were analysed using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. The results were also analyzed using sorption kinetics models, pseudo-first-, pseudo-second-order, intra-particle and film diffusion models. From the Dubinin-Radushkevich and Temkin isotherm models the mean free energy and heat of sorption were calculated to be 7.45 kJ mol?1, respectively 1×10?4 kJ mol?1, which indicates that zinc sorption is characterized by a physisorption process. Kinetic studies showed that the adsorption followed a pseudo-second-order kinetic model. 相似文献
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Emilia Janiszewska-Turak Katarzyna Rybak Ewelina Grzybowska Ewelina Konopka Dorota Witrowa-Rajchert 《Molecules (Basel, Switzerland)》2021,26(12)
Vegetable processing pomace contains valuable substances such as natural colors that can be reused as functional ingredients. Due to a large amount of water, they are an unstable material. The aim of our research was to assess how the pretreatment method (thermal or nonthermal) affects the properties of powders obtained from beet juice and pomace after the freeze-drying process. The raw material was steamed or sonicated for 10 or 15 min, and then squeezed into juice and pomace. Both squeezed products were freeze-dried. The content of dry substance; L*, a*, and b* color parameters; and the content of betalain pigments were analyzed. Pretreatments increased the proportion of red and yellow in the juices. Steam and ultrasound caused a significant reduction in parameter b* in the dried pomace. A significant increase in betanin in lyophilizates was observed after pretreatment with ultrasound and steam for 15 min. As a result of all experiments, dried juices and pomaces can also be used as a colorant source. However, there is higher potential with pomaces due to their additional internal substances as well as better storage properties. After a few hours, juice was sticky and not ready to use. 相似文献
25.
Luana Malacaria Giuseppina Anna Corrente Amerigo Beneduci Emilia Furia Tiziana Marino Gloria Mazzone 《Molecules (Basel, Switzerland)》2021,26(9)
This review focuses on the ability of some natural antioxidant molecules (i.e., hydroxycinnamic acids, coumarin-3-carboxylic acid, quercetin, luteolin and curcumin) to form Al(III)- and Fe(III)-complexes with the aim of evaluating the coordination properties from a combined experimental and theoretical point of view. Despite the contributions of previous studies on the chemical properties and biological activity of these metal complexes involving such natural antioxidants, further detailed relationships between the structure and properties are still required. In this context, the investigation on the coordination properties of Al(III) and Fe(III) toward these natural antioxidant molecules might deserve high interest to design water soluble molecule-based metal carriers that can improve the metal’s intake and/or its removal in living organisms. 相似文献
26.
Cristina Bucur Mihaela Badea Mariana Carmen Chifiriuc Coralia Bleotu Emilia Elena Iorgulescu Irinel Adriana Badea Maria Nicoleta Grecu Veronica Lazăr Oana-Irina Patriciu Dana Marinescu Rodica Olar 《Journal of Thermal Analysis and Calorimetry》2014,115(3):2179-2189
Novel complexes of M2LCl4·nH2O type (M:Ni, n = 4; M:Cu, n = 3 and M:Zn, n = 0; L: ligand resulted from 1,4-phenylenediamine, 3,6-diazaoctane-1,8-diamine and formaldehyde one-pot condensation) were synthesized and characterised by microanalytical, ESI–MS, IR, UV–Vis, 1H NMR and EPR spectra, magnetic data at room temperature and molar conductivities as well. The electrochemical behaviour of complexes was investigated by cyclic voltammetry. Simultaneous TG/DTA measurements were performed in order to evidence the thermal behaviour of the obtained complexes. Processes such as water elimination, fragmentation and oxidative degradation of the organic ligand as well as chloride elimination occurred during thermal decomposition. The antimicrobial assays demonstrate that the compounds exhibited good antibacterial activity, especially against S. aureus and E. coli strains, the most active being the copper(II) complex, which also exhibited the most prominent anti-biofilm effect, suggesting its potential use for the development of new antimicrobial agents. The biological activity was correlated with log P ow values. All complexes disrupt the membrane integrity of HCT 8 tumour cells. 相似文献
27.
Sunto Fissata una superficie algebrica liscia X sopra un campo algebricamente chiuso e di caratteristica 0, e una curva ridotta C su X, si introduce, per ogni -upla di numeri naturali m1,..., m, uno schema W=W(C, m1,..., m), parametrizzante le curve del sistema lineare ¦C¦ con punti multipli ordinari di molteplicità almeno m1,..., m. Si studia W in relazione con la configurazione delie singolarità e delle componenti irriducibili di C. Si prova in particolare un teorema di «virtuale connessione», che permette di stabilire l'esistenza di curve irriducibili in alcuni di tali schemi W.
Membro del G.N.S.A.G.A. del C.N.R. 相似文献
Membro del G.N.S.A.G.A. del C.N.R. 相似文献
28.
Prof. Piotr Bałczewski Dr. Emilia Kowalska Dr. Ewa Różycka-Sokołowska Dr. Joanna Skalik Dr. Krzysztof Owsianik Dr. Marek Koprowski Dr. Bernard Marciniak Dr. Dariusz Guziejewski Prof. Witold Ciesielski 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(62):14148-14161
The highly substituted mono-aryl/alkylthio-(hetero)acenes prepared in this study have been found to be thermally more stable (Tdecomp.=331–354 °C) than the known di-aryl/alkylthio-substituted acenes by an average of 25 °C. They are also much more photostable at 254 and 365 nm (in both argon and air) than the parent anthracene and other reported anthracenes. The most photostable aryl/alkylthio-anthracenes at 254 nm were found to be 60–70 (in air) and 130 (in argon) times more stable in solution than the unsubstituted anthracene, and much more stable than known EDG/EWG-substituted anthracenes (EDG=electron-donating group, EWG=electron-withdrawing group) with an extended aromatic core. Furthermore, the acenes showed significantly higher photostability at 365 nm in both air and argon. The anthracenes were obtained by the novel thio-Friedel–Crafts/Bradsher cyclization reaction of hitherto unknown [o-(1,3-dithian-2-yl)aryl](aryl)methyl thioethers. The developed approach provides a general access to mono-aryl/alkylthio-substituted (hetero)acene frameworks containing at least three fused (hetero)aromatic rings. The characteristic feature of this approach, which leads to highly substituted acenes, is that the substituents, unlike in other methods, may be introduced at an early stage of the synthesis. DFT and TD-DFT calculations confirmed the stabilizing role of the aryl/alkylthio substituent in the mono-aryl/alkylthio-substituted anthracenes, which are the most stable anthracenes prepared to date. Their high photostability is mainly due to the quenching of singlet oxygen by the acene and the quenching of the acene S1 state by molecular oxygen. 相似文献
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