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151.
Roberto Mattioli Daniel Di Risola Rodolfo Federico Alessia Ciogli Francesco Gasparrini Claudio Villani Mario Fontana Anna Maggiore Maria dErme Luciana Mosca Antonio Francioso 《Molecules (Basel, Switzerland)》2022,27(7)
trans-Resveratrol is a natural bioactive compound with well-recognized health promoting effects. When exposed to UV light, this compound can undergo a photochemically induced trans/cis isomerization and a 6π electrochemical cyclization with the subsequent formation of 2,4,6-trihydroxyphenanthrene (THP). THP is a potentially harmful compound which can exert genotoxic effects. In this work we improved the chromatographic separation and determination of the two resveratrol isomers and of THP by using a non-commercial pentafluorophenyl stationary phase. We assessed the effect of natural deep eutectic solvents (NaDES) as possible photo-protective agents by evaluating cis-resveratrol isomer and THP formation under different UV-light exposure conditions with the aim of enhancing resveratrol photostability and inhibiting THP production. Our results demonstrate a marked photoprotective effect exerted by glycerol-containing NaDES, and in particular by proline/glycerol NaDES, which exerts a strong inhibitory effect on the photochemical isomerization of resveratrol and significantly limits the formation of the toxic derivative THP. Considering the presence of resveratrol in various commercial products, these results are of note in view of the potential genotoxic risk associated with its photochemical degradation products and in view of the need for the development of green, eco-sustainable and biocompatible resveratrol photo-stable formulations. 相似文献
152.
153.
Riet Dams Elena Bernabe Anna Nicoletti Claudio Loda Luca Martini Damiano Papini 《Rapid communications in mass spectrometry : RCM》2010,24(17):2650-2654
The introduction of Quality by Design (QbD) in Drug Development has resulted in a greater emphasis on chemical process understanding, in particular on the origin and fate of impurities. Therefore, the identification and quantitation of low level impurities in new Active Pharmaceutical Ingredients (APIs) play a crucial role in project progression and this has created a greater need for sensitive and selective analytical methodology. Consequently, scientists are constantly challenged to look for new applications of traditional analytical techniques. In this context a normal‐phase liquid chromatography/electrospray ionization mass spectrometry (LC/ESI‐MS) method was developed to determine the amount of a de‐fluorinated analogue impurity in Casopitant Mesylate, a new API under development in GlaxoSmithKline, Verona. Normal‐phase LC provided the selectivity needed between our target analyte and Casopitant, while a single quadrupole mass spectrometer was used to ensure the sensitivity needed to detect the impurity at <0.05%w/w. Standard solutions and samples were prepared in heptane/ethanol (50:50, v/v) containing 1% of 2 M NH3 in ethanol; the mobile phase consisted of heptane/ethanol (95:5, v/v) with isocratic elution (flow rate: 1.0 mL/min, total run time: 23 min). To allow the formation of ions in solutions under normal‐phase (apolar) conditions, a post‐column infusion of a solution of 0.1% v/v of formic acid in methanol was applied (flow rate: 200 µL/min). The analysis was carried out in positive ion mode, monitoring the impurity by single ion monitoring (SIM). The method was fully validated and its applicability was demonstrated by the analysis of real‐life samples. This work is an example of the need for selective and accurate methodology during the development of a new chemical entity in order to develop an appropriate control strategy for impurities to ultimately ensure patient safety. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
154.
Knut Bakke Claudio Furtado J. R. Nascimento 《The European Physical Journal C - Particles and Fields》2009,60(3):501-507
We investigate the relativistic and non-relativistic quantum dynamics of a neutral spin-1/2 particle subject to an external
electromagnetic field in the presence of a cosmic dislocation. We analyze the explicit contribution of the torsion in the
geometric phase acquired in the dynamics of this neutral spinorial particle. We discuss the influence of the torsion in the
relativistic geometric phase. Using the Foldy–Wouthuysen approximation, the non-relativistic quantum dynamics is studied and
the influence of the torsion on the Aharonov–Casher and He–McKellar–Wilkens effects are discussed.
An erratum to this article can be found at 相似文献
155.
Lucas Pizzuti Luciana A. Piovesan Alex F.C. Flores Frank H. Quina Claudio M.P. Pereira 《Ultrasonics sonochemistry》2009,16(6):728-731
An efficient and green synthesis of thiocarbamoyl-3,5-diaryl-4,5-dihydro-1H-pyrazoles via the condensation of chalcones with thiosemicarbazide in ethanol and KOH under ultrasound irradiation is reported. The products were isolated in good yields after short reaction times. 相似文献
156.
157.
158.
Pierluigi?Contucci Cristian?Giardinà Claudio?GibertiEmail author Giorgio?Parisi Cecilia?Vernia 《Journal of statistical physics》2011,143(1):1-10
We numerically investigate the spin glass energy interface problem in three dimensions. We analyze the energy cost of changing
the overlap from −1 to +1 at one boundary of two coupled systems (in the other boundary the overlap is kept fixed to +1).
We implement a parallel tempering algorithm that simulates finite temperature systems and works with both cubic lattices and
parallelepiped with fixed aspect ratio. We find results consistent with a lower critical dimension D
c
=2.5. The results show a good agreement with the mean field theory predictions. 相似文献
159.
160.
Tiecco M Testaferri L Santi C Tomassini C Marini F Bagnoli L Temperini A 《Chemistry (Weinheim an der Bergstrasse, Germany)》2002,8(5):1118-1124
The synthesis of the new chiral non-racemic sulfur-containing diselenide, di-2-methoxy-6-[(1S)-1-(methylthio)ethyl]phenyl diselenide, is described. When treated with ammonium persulfate this diselenide is transformed into the corresponding selenenyl sulfate, which acts as a strong electrophilic reagent and adds to alkenes, in the presence of methanol or water, to afford the products of selenomethoxylation or selenohydroxylation, respectively, with excellent diastereoselectivities. Starting from alkenes containing internal nucleophiles, asymmetric cyclofunctionalization reactions also resulted in good chemical yields, complete regioselectivities, and high diastereoselectivities. This sulfur-containing diselenide can also be used in catalytic amounts to promote one-pot selenenylation-deselenenylation processes, from which several types of products can be obtained in high yield and with good enantiomeric excess. 相似文献