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31.
Valeria Alzari Daniele Nuvoli Davide Sanna Andrea Ruiu Alberto Mariani 《Journal of polymer science. Part A, Polymer chemistry》2016,54(1):63-68
The frontal ring opening metathesis polymerization (FROMP) of dicyclopentadiene (DCPD) in the presence of limonene, using second generation Grubbs’ catalysts, is reported. The effect of limonene on the amount of catalyst and the typical frontal polymerization parameters, as maximum temperature (Tmax) and velocity of the front (Vf), is studied. In addition, the influence of limonene on the mechanical properties of the polymeric samples is reported. Finally, a deep study on the swelling properties of polymers is done. It has been demonstrated that limonene acts as both inhibitor and solvent of the catalyst. The Tmax, Vf, Tg, and Young modulus values decrease as the amount of limonene increases, and the polymer samples swell in THF depending on the amount of limonene. All results indicate that the limonene addition on FROMP of results in advantages on the polymerization reaction and its parameters and on the final polymer properties. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 63–68 相似文献
32.
The effect of infiltrating on a La0.85Sr0.15MnO3/Ce0.9Gd0.1O1.95 11-layer electrochemical reactor with CeO2 and Ce0.8Pr0.2O2?δ was studied in propene oxidation at open-circuit voltage and under polarization as a function of reaction temperature. This work outlined the importance of catalytic and electrochemical properties of infiltrated material on the ability to increase propene conversion under polarization with good faradaic efficiency. Electrochemical impedance spectroscopy was used to study the effect of infiltration material on electrode properties. The infiltration of a mixed ionic and electronic conductor, like Ce0.8Pr0.2O2?δ , increased the electrode performance at low temperature but decreased the lifetime of the oxygen ion promoters on the catalyst/electrode surface, reducing the faradaic efficiency of the reaction. The infiltration of CeO2 provided high propene conversion at open circuit and high effect of polarization associated with good faradaic efficiency, especially at low temperature. 相似文献
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34.
Monia Renzi Antonietta Specchiulli Davide Baroni Tommaso Scirocco Lucrezia Cilenti Silvia Focardi 《International journal of environmental analytical chemistry》2013,93(6):676-697
Samples of surface sediments and tissues (liver and muscle) of commercially available European silver eels (Anguilla anguilla L.) collected from Varano lagoon (Italy) were analysed to determine trace element contents. Univariate and multivariate analyses were performed to highlight both the differences between sampling sites and the influence of channel discharges. Atomic ratios indices for sediment data and biological enrichment factors (BEF) for eel tissues were calculated in order to evaluate the enrichment factor due to human activities. The highest levels of As (11.9?µg?g?1) and Zn (14.1?µg?g?1) were observed in the south-eastern zone of the lagoon, which is influenced by urban and agricultural discharges. The low levels of Hg observed in this study (0.04?µg?g?1) led us to exclude both natural and human local sources of this element. Trace element concentrations of all elements were lower in muscle than in liver tissue. Significant enrichment of Cu and Zn was found in livers. 相似文献
35.
Antonio Tognazzi Arduino M. Dattilo Luca Bracchini Claudio Rossi Davide Vione 《International journal of environmental analytical chemistry》2013,93(15):1679-1688
It is known that the compound 2,4-dichloro-6-nitrophenol (2,4DC6NP) is formed upon nitration of 2,4-dichlorophenol, which in turn is a transformation intermediate of the herbicide dichlorprop. However, the chemical and spectroscopic characteristics of 2,4DC6NP, as well as its toxicity, are poorly known. This work shows that 2,4DC6NP behaves as a diprotic acid in aqueous solutions, with pKa values of 3.0?±?0.9 and 4.9?±?0.5. At pH?<?3, 2,4DC6NP would undergo protonation. The absorption spectra suggest that anionic 2,4DC6NP, which prevails at pH?>?5 would have an ortho-quinoid structure that is responsible for the absorption peak centred at 428?nm. Considering that 2,4DC6NP has been detected in the brackish lagoons of the Rhône delta (southern France), where its levels are comparable to those of the parent herbicide, it is necessary to examine the possible effects of 2,4DC6NP on the species living in that environment. For this reason, the acute toxicity of the anionic form of 2,4DC6NP was assessed for the brine shrimp Artemia salina, a zooplankton species that lives both in brackish and in saline aquatic environments. The toxicity test yielded a LC20 value of 8?±?2?mg?L?1 and a LC50 value of 18.7?±?0.8?mg?L?1. Such values are safely higher than the maximum detected concentration of 2,4DC6NP in the Rhône delta lagoons. Further studies should be concentrated on the long-term effects of 2,4DC6NP, and in particular on its potential genotoxicity. 相似文献
36.
Dr. Alessandro Barge Marina Caporaso Prof. Giancarlo Cravotto Dr. Katia Martina Dr. Paolo Tosco Prof. Silvio Aime Dr. Carla Carrera Dr. Eliana Gianolio Dr. Giorgio Pariani Dr. Davide Corpillo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(36):12086-12092
We report the synthesis and characterization of a water‐soluble, star‐shaped macromolecular platform consisting of eight β‐cyclodextrin (β‐CD) units anchored to the narrower rim of a γ‐CD core through bis(triazolyl)alkyl spacers. The efficient synthetic protocol is based on the microwave (MW)‐promoted Cu‐catalyzed 1,3‐dipolar cycloaddition of CD monoazides to CD monoacetylenes. The ligand‐hosting capability of the construct has been assessed by relaxometric titration and nuclear magnetic relaxation dispersion (NMRD) profiling, which showed it to be good, and this was supported by molecular dynamics simulations. To demonstrate the feasibility of obtaining supramolecular structures with high hosting ability, we designed a dimeric platform, formed by joining two nonamers through the γ‐CD cores through a bis(lithocholic acid) linker. With a view to the potential biological applications, cytotoxicity and extent of binding to human serum albumin were assessed. The properties of this dendrimeric multicarrier make it suitable for pharmaceutical and diagnostic purposes, ranging from targeted drug delivery to molecular imaging. 相似文献
37.
We investigate the thermal conductivity of single-wall carbon nanotubes (SWCNT) either isolated or in contact with external media by using equilibrium molecular dynamics and the Boltzmann transport equation. We show that, contrary to existing controversies, both methods yield a finite value of the thermal conductivity for infinitely long tubes, as opposed to the case of 1D, momentum-conserving systems. Acoustic and flexure modes with mean free paths of the order of a few microns are identified as major contributors to the high value of SWCNT conductivity. We also find that the interaction with an external medium may substantially decrease the lifetime of the low-frequency vibrations, reducing the thermal conductivity by up to 2 orders of magnitude. 相似文献
38.
Cristina Cornaro Simona Bartocci Davide Musella Cecilia Strati Alessandro Lanuti Simone Mastroianni Stefano Penna Andrea Guidobaldi Fabrizio Giordano Eleonora Petrolati Thomas M. Brown Andrea Reale Aldo Di Carlo 《Progress in Photovoltaics: Research and Applications》2015,23(2):215-225
New generation photovoltaic (PV) devices such as polymer and dye sensitized solar cells (DSC) have now reached a more mature stage of development, and among their various applications, building integrated PVs seems to have the most promising future, especially for DSC devices. This new generation technology has attracted an increasing interest because of its low cost due to the use of cheap printable materials and simple manufacturing techniques, easy production, and relatively high efficiency. As for the more consolidated PV technologies, DSCs need to be tested in real operating conditions and their performance compared with other PV technologies to put into evidence the real potential. This work presents the results of a 3 months outdoor monitoring activity performed on a DSC mini‐panel made by the Dyepower Consortium, positioned on a south oriented vertical plane together with a double junction amorphous silicon (a‐Si) device and a multi‐crystalline silicon (m‐Si) device at the ESTER station of the University of Rome Tor Vergata. Good performance of the DSC mini‐panel has been observed for this particular configuration, where the DSC energy production compares favorably with that of a‐Si and m‐Si especially at high solar angles of incidence confirming the suitability of this technology for the integration into building facades. This assumption is confirmed by the energy produced per nominal watt‐peak for the duration of the measurement campaign by the DSC that is 12% higher than that by a‐Si and only 3% lower than that by m‐Si for these operating conditions. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
39.
Christian Gentzsch Kerstin Seier Antonios Drakopoulos Dr. Marie-Lise Jobin Dr. Yann Lanoiselée Dr. Zsombor Koszegi Dr. Damien Maurel Dr. Rémy Sounier Dr. Harald Hübner Prof. Dr. Peter Gmeiner Dr. Sébastien Granier Prof. Dr. Davide Calebiro Prof. Dr. Michael Decker 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(15):6014-6020
μ-Opioid receptors (μ-ORs) play a critical role in the modulation of pain and mediate the effects of the most powerful analgesic drugs. Despite extensive efforts, it remains insufficiently understood how μ-ORs produce specific effects in living cells. We developed new fluorescent ligands based on the μ-OR antagonist E-p-nitrocinnamoylamino-dihydrocodeinone (CACO), that display high affinity, long residence time and pronounced selectivity. Using these ligands, we achieved single-molecule imaging of μ-ORs on the surface of living cells at physiological expression levels. Our results reveal a high heterogeneity in the diffusion of μ-ORs, with a relevant immobile fraction. Using a pair of fluorescent ligands of different color, we provide evidence that μ-ORs interact with each other to form short-lived homodimers on the plasma membrane. This approach provides a new strategy to investigate μ-OR pharmacology at single-molecule level. 相似文献
40.
IRMPD Spectra of Protonated Hydroxybenzaldehydes: Evidence of Torsional Barriers in Carboxonium Ions
Prof. Barbara Chiavarino Prof. Otto Dopfer Prof. Maria Elisa Crestoni Dr. Davide Corinti Dr. Philippe Maître Prof. Simonetta Fornarini 《Chemphyschem》2020,21(8):749-761
Protonation at the formyl oxygen atom of benzaldehydes leading to the formation of carboxonium ions yields two distinct isomers, depending on the relative orientation of the proton either cis or trans with respect to the hydrogen atom on the adjacent carbon. In this context, the IR multiple photon dissociation (IRMPD) spectra of protonated ortho, meta, and para-hydroxybenzaldehydes ( OH−BZH+ ), delivered into the gas phase by electrospray ionization of hydro-alcoholic solutions, are reported in the 3200–3700 cm−1 spectral range. This range is characteristic of O−H stretching modes and thus able to differentiate cis and trans carboxonium isomers. Comparison between IRMPD spectra and DFT calculations at the B3LYP/6-311++G(2df2p) level suggests that for both p- OH−BZH+ and m- OH−BZH+ only cis conformers are present in the ion population analyzed. For o- OH−BZH+ , IRMPD spectroscopy points to a mixture comprising one trans and more than one cis conformers. The energy barrier for cis–trans isomerization calculated for each OH−BZH+ isomer is a measure of the degree of π-electron delocalization. Furthermore, IRMPD spectra of p- OH−BZH+ , m- OH−BZH+ and protonated phenol (this last used as reference) were recorded also in the fingerprint range. Both the observed C−O and O−H stretching vibrations appear to be a measure of π-electron delocalization in the ions. 相似文献