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91.
Quantification of tenatoprazole in rat plasma by HPLC: validation and its application to pharmacokinetic studies 总被引:1,自引:0,他引:1
Nirogi R Kandikere V Mudigonda K Bhyrapuneni G 《Biomedical chromatography : BMC》2007,21(12):1240-1244
A simple, reliable HPLC method with UV detection (295 nm) in rat plasma was developed and validated for quantification of tenatoprazole, a novel proton pump inhibitor, which is in clinical trials. Following a single-step liquid-liquid extraction, the analyte and internal standard were separated using an isocratic mobile phase on a reverse phase C(18) column. The lower limit of quantitation was 20 ng/mL, with a relative standard deviation of less than 10%. A linear dynamic range of 20-6000 ng/mL was established. This HPLC method was validated with between-batch and within-batch precision of 2.9-6.3 and 1.4-5.8%, respectively. The between-batch and within-batch accuracy was 95.1-104.1 and 92.4-101.0%, respectively. This validated method is simple and repeatable enough to be used in pharmacokinetic studies. 相似文献
92.
Nirogi RV Kandikere VN Shukla M Mudigonda K Maurya S Komarneni P 《Biomedical chromatography : BMC》2007,21(2):209-216
A rapid high-performance liquid chromatography/positive ion electrospray tandem mass spectrometry method was developed and validated for the quantification of fexofenadine in human plasma using mosapride as internal standard. Following solid-phase extraction, the analytes were separated using an isocratic mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M+H]+ ions, m/z 502/466 for fexofenadine and m/z 422/198 for the IS. The method exhibited a linear dynamic range of 1-500 ng/mL for fexofenadine in human plasma. The lower limit of quantification was 1 ng/mL with a relative standard deviation of less than 5% for fexofenadine. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. The total chromatographic run time of 2 min for each sample made it possible to analyze more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies. 相似文献
93.
Branched macromolecular structures are now an important area of research for enhanced two-photon absorption (TPA) cross sections. The mechanism of this enhancement has been suggested as a complex interplay between intramolecular interactions and the extent of charge-transfer character in the branches. In order to probe these processes more clearly, excited-state dynamics of multibranched chromophores by means of femtosecond transient absorption spectroscopy are reported. Investigations have been carried out on the PRL dye series (PRL-101, PRL-501, PRL-701), which have shown cooperative enhancement of the TPA cross section. Upon photoexcitation, transient absorption measurements have shown the presence of a localized charge-transfer (intramolecular charge transfer, ICT) state independent of branching. The results point to ultrafast localization of charge in this particular system of chromophores. Pump-probe measurements in highly polar solvents have shown the presence of a nonemissive charge-transfer state which is a solvent stabilized and conformationally relaxed state. The population of this nonemissive state increases from monomer to trimer, and thus, it has been used as indicator of the polar nature of the Franck-Condon state. These results have shown an increase of charge-transfer character of the excited state with an increase in branching, and this explains the relative increase in the two-photon cross section of the PRL series. 相似文献
94.
P. V. Subba Rao G. Krishna Rao K. Ramakrishna G. Rambabu A. Satyanarayana 《国际化学动力学杂志》1997,29(3):171-179
Iron(III)-2,2′-bipyridyl complex obtained, in situ, by direct mixing of iron(III) and 2,2′-bipyridyl, oxidizes aniline, thiourea, and ascorbic acid. The reaction is markedly accelerated by sodium dodecyl sulphate. The rate-[surfactant] profile exhibits a maximum. The kinetic analysis of the micellar effect has been carried out using Berezin's approach. The binding constants of 2,2′-bipyridyl, aniline, thiourea, and ascorbic acid have been determined. © 1997 John Wiley & Sons, Inc. Int J Chem Kinet 29: 171–179, 1997. 相似文献
95.
Raunak Tamrakar Vikas Dubey N. Kumar Swamy Ratnesh Tiwari S. V. N. Pammi P. V. Ramakrishna 《Research on Chemical Intermediates》2013,39(8):3919-3923
The present paper reports thermoluminescence (TL) glow curves of Eu3+-doped Y2O3 phosphor with different ultraviolet (UV) exposure times. The glow peak shows second-order kinetics of Eu3+-doped Y2O3, and corresponding kinetic parameters were evaluated using the peak shape method. Calculations of trap depth were carried out using different methods. The kinetics order, activation energy, and frequency factor were calculated. The recorded glow curve shifts towards higher intensity with longer UV exposure. The heating rate used for recording TL was 3.0 °C s?1. Particle size and structure were verified by X-ray diffraction (XRD) pattern and morphology by scanning electron microscopy (SEM) imaging. 相似文献
96.
P. Lakshmi Praveen Ramakrishna D. S. Durga P. Ojha 《Molecular Crystals and Liquid Crystals》2017,643(1):76-82
In the present article, UV spectral characterization of a smectic-C liquid crystal 4,4′-bis(n-alkoxy)azoxybenzene (n = 14) (C40H66N2O3) has been carried out. Structure of the molecule has been optimized using the Density functional B3LYP with 6-31+G (d) basis set using crystallographic geometry as input. The absorption spectra have been estimated in the UV region by employing the DFT method, semiempirical CNDO/S and INDO/S parameterizations. The oscillator strength (f) and vertical transition energy (EV) have been reported corresponding to absorption wavelength (λmax). These values have been compared with the experimental value reported in the literature to offer theoretical support to the experimental value. Further, some electrochemical properties have been reported for the molecule. 相似文献
97.
Sadagopan Raghavan A. RajenderM.Abdul Rasheed S.Ramakrishna Reddy 《Tetrahedron letters》2003,44(45):8253-8256
A novel, unprecedented transformation of δ-hydroxysulfoxides into substituted tetrahydrofurans by a silicon promoted Pummerer type reaction is disclosed. The transformation is shown to be general and is brought about under very mild reaction conditions. The products with the sulfide group at the anomeric carbon provide a suitable handle to carry out further transformations. 相似文献
98.
Bada Jayappa Rudresha Badekai Ramachandra Bhat Dileep Ramakrishna John Kiran Anthony H.W. Lee F. Rotermund 《Optics & Laser Technology》2012,44(4):1180-1183
A femtosecond differential optical Kerr gate (DOKG) and Z-scan techniques, have been applied to investigate the third-order optical nonlinearity of composite film of the coordination complex [PdLPPh3] (L=N-(2-pyridyl)-N′-(salicylidene)hydrazine, PPh3=triphenylphosphine). Film exhibits superior nonlinear optical properties in the near-infrared spectral region. The nonlinear response time and third-order nonlinear optical susceptibility of complex were found to be≤90 fs and 3.9×10?10 esu, respectively. The Z-scan result shows that saturable absorption property of the film and its nonlinear absorption coefficient of the sample was found to be ?23 cm/GW. 相似文献
99.
Biswanath Das Boddu Shashi Kanth Anjoy Majhi Kongara Ravinder Reddy 《Heteroatom Chemistry》2008,19(6):630-633
(Bromodimethyl)sulfonium bromide has efficiently been employed for chemo‐ and stereoselective conversions of β‐dicarbonyl compounds into β‐enaminones and β‐enaminoesters by a treatment with amines at room temperature under solvent‐free conditions. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:630–633, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20477 相似文献
100.
Galla Raju Rajesh NomulaKallaganti V.S. Ramakrishna Palakodety Radha Krishna 《Tetrahedron letters》2014
The first total synthesis of (6Z,9S)-3,4-trans-9-hydroxy-3-methyldodec-cis-6-en-4-olide and (6Z)-3,4-trans-9-oxo-3-methyldodec-cis-6-en-4-olide was achieved in a convergent pathway. The salient features of our synthesis include Ohira–Bestmann reaction, regioselective alkyne addition to terminal epoxide, TEMPO/BAIB mediated oxidative lactonization, and partial hydrogenation. 相似文献