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81.
Summary The determination of phenyl hydrazine is done by reaction with ammonium molybdate; the pink colour procedud is extracted inton-butanol. 100–1300g of phenyl hydrazine can be determined at 510 nm. The effect of time, temperature, ammonium molybdate concentration and interferences has been studied.
Zusammenfassung Die Bestimmung von Phenylhydrazin erfolgt auf der Grundlage seiner Reaktion mit Ammoniummolybdat. Die rosa Färbung wird mitn-Butanol extrahiert. 0,1–1,3 mg Phenylhydrazin können bei 510 nm gemessen werden. Der Einfluß der Reaktionszeit, der Temperatur, der Reagenskonzentration sowie auftretende Störungen wurden untersucht.相似文献
82.
P. Sharma S. Kumbhat C. Rawat 《International journal of environmental analytical chemistry》2013,93(3-4):201-207
Abstract A differential pulse polarographic method has been developed for the simultaneous low level determination of nickel and cobalt in the presence of furildioxime in natural waters. The nature of the electrode processes was studied with cyclic voltammetry. Limits of determination of 0.4 μg/L and 0.15 μg/L were achieved for nickel and cobalt respectively 相似文献
83.
Devendra Singh M. S. M. Rawat Ajay Semalty Mona Semalty 《Journal of Thermal Analysis and Calorimetry》2013,111(3):2069-2077
Delivery of poorly soluble drugs results in poor absorption and low bioavailability to the systemic circulation. Chrysophanol (1,8-dihydroxy 3-methyl anthraquinone) a plant derived herbal drug is well known for its strong anti-inflammatory, anti-mutagenic, and anti-carcinogenic activities but poor aqueous solubility (hence the lower dissolution rate), is a major barrier in its intestinal absorption. To improve the bioavailability and prolong its duration in the body system, its phospholipid complex was prepared and evaluated for various physicochemical parameters like encapsulation efficiency, scanning electron microscopy, differential scanning calorimetry (DSC), X-ray powder diffractometry (X-RPD), IR spectroscopy, aqueous/n-octanol solubility, and dissolution study. The phospholipid complex of chrysophanol was found, fluffy and porous with rough surface morphology. FTIR, DSC, and X-RPD data confirmed the complex formation. The 89.1 % of chrysophanol was encapsulated in the phospholipid complex. The aqueous solubility of chrysophanol was improved from 0.60 to 30.09 μg ml?1 in the prepared complex. The improved dissolution was shown by the complex (which showed continuous release up to 83.67 % of chrysophanol) at the end of 12 h, in comparison to free drug (which showed a total of only 45.12 % drug release at the end of 12 h of dissolution study). 相似文献
84.
Parijat Sarkar Kaleeckal G. Harikumar Satinder S. Rawat Sanjib Das Tushar K. Chakraborty Amitabha Chattopadhyay 《Molecules (Basel, Switzerland)》2021,26(13)
Serotonin is a neurotransmitter that plays a crucial role in the regulation of several behavioral and cognitive functions by binding to a number of different serotonin receptors present on the cell surface. We report here the synthesis and characterization of several novel fluorescent analogs of serotonin in which the fluorescent NBD (7-nitrobenz-2-oxa-1,3-diazol-4-yl) group is covalently attached to serotonin. The fluorescent ligands compete with the serotonin1A receptor specific radiolabeled agonist for binding to the receptor. Interestingly, these fluorescent ligands display a high environmental sensitivity of their fluorescence. Importantly, the human serotonin1A receptor stably expressed in CHO-K1 cells could be specifically labeled with one of the fluorescent ligands with minimal nonspecific labeling. Interestingly, we show by spectral imaging that the NBD-labeled ligand exhibits a red edge excitation shift (REES) of 29 nm when bound to the receptor, implying that it is localized in a restricted microenvironment. Taken together, our results show that NBD-labeled serotonin analogs offer an attractive fluorescent approach for elucidating the molecular environment of the serotonin binding site in serotonin receptors. In view of the multiple roles played by the serotonergic systems in the central and peripheral nervous systems, these fluorescent ligands would be useful in future studies involving serotonin receptors. 相似文献
85.
Pramana - This work concerns the modelling of the dynamics of polarisation of a centrosymmetric material subjected to an amplitude-modulated excitation (AME). The dynamic equation obtained for the... 相似文献
86.
S. K. Aggarwal G. Chourasiya R. K. Duggal C. P. Singh A. S. Rawat H. C. Jain 《Fresenius' Journal of Analytical Chemistry》1986,323(2):148-152
Summary A method is described for determining the plutonium concentration by Isotope Dilution Alpha Spectrometry (IDAS) using238Pu as a spike. It involves the addition of a pre-calibrated spike solution to a known aliquot of the plutonium sample solution followed by source preparation using TEG as a spreading agent. The results obtained on a number of samples using this method are compared with those of IDMS using242Pu as a spike as well as with those obtained by IDAS using TTA for purification, with respect to precision and accuracy. Precision of 0.3–0.5% and an accuracy of 0.5% is demonstrated. This method eliminates the need of any separation and purification of plutonium from241 Am and a bulk of other impurities.
Plutoniumbestimmung durch Isotopenverdünnungs-Alpha-Spektrometrie ohne Abtrennung von Americium-241 und anderen Verunreinigungen
Zusammenfassung Bei dem beschriebenen Verfahren der Isotopenverdünnungs-Alpha-Spektrometrie (IDAS) wird238Pu als Spike benutzt. Eine vorgeeichte Spike-Lösung wird zu einem bekannten Aliquot der Probe gegeben und anschließend die Strahlungsquelle unter Verwendung von Tetraethylenglykol als Spreading-Reagens vorbereitet. Die nach diesem Verfahren erhaltenen Ergebnisse werden in bezug auf Präzision und Genauigkeit mit solchen verglichen, die mit Isotopenverdünnungs-Massenspektrometrie unter Verwendung von242Pu als Spike oder mit IDAS unter Verwendung von Thenoyltrifluoraceton zur Reinigung erhalten wurden. Eine Präzision von 0,3–0,5% und eine Genauigkeit von 0,5% wurden erzielt. Durch das beschriebene Verfahren erübrigt sich eine Reinigung des Pu von241Am und anderen Verunreinigungen.相似文献
87.
In this paper, an optical heterodyne interferometric detection model with a frequency-ramped laser diode (LD) has been analyzed. The effect of the nonlinearity of the LD source on the optical heterodyne interferometry has been investigated in two different ways, which are the power-distortion Fourier series analysis and the harmonic distortion analysis. The general formulation between the tangent of the tested phase and the interference fringe have been presented with the analysis of the beat signal in the frequency domain by each methodology. The numerical results of these formulations have been presented. 相似文献
88.
Mössbauer studies of the Itawa-Bhopji meteorite fallen on May 30, 2000 in Rajasthan, India, show that the main iron minerals in it are Fe–Ni (kamacite/taenite), troilite, olivine and pyroxene. These provide characteristic signatures of an ordinary chondrite. Mössbauer absorption areas corresponding to different phases favour its classification as L/LL-type ordinary chondrite. The iron in the olivine is unusually high and the metallic iron is quite low, showing that it has faced oxidizing conditions prior to fall. 相似文献
89.
Usha Chandra Prerana Mudgal Manoj Kumar Rajeev Rawat G. Parthasarathy Nita Dilawar A. K. Bandyopadhyay 《Hyperfine Interactions》2005,163(1-4):129-141
We report here the Mössbauer measurements on nanocrystalline perovskite structured manganite La0.8Sr0.2Mn0.8Fe0.19
57Fe0.01O3 as a function of pressure up to 10 GPa at room temperature. The nanocrystalline sample, prepared by sol–gel technique found to have crystallite sizes of ∼138 ± 10 Å. Zero-field electrical resistivity measurements with temperature support the nanocrystalline nature. At ambient pressure, Fe3+ as well as Fe4+ ions are distributed in two different environments – Fe3+ in low symmetric site surrounded by Mn3+ ions only while Fe4+ in high symmetric site with at least one Mn3+ ion. Pressure seems to affect the higher symmetric site. A sudden increase in isomer shift at 0.52 GPa indicates the first order phase transition representing the transformation of Fe4+ to Fe3+. Another transition at 3.7 GPa, represents the presence of Fe3+ in single kind of environment. Pressure dependence of electrical resistivity measurements verifies the transitions attributing the first order transition to the cross over of localized-electron to band magnetism. 相似文献
90.