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11.
Rashmi C. Kulkarni S. Samundeeswari Farzanabi Shaikh Nirmala S. Naik Jyoti M. Madar Lokesh A. Shastri Vinay A. Sunagar 《Journal of fluorescence》2017,27(5):1613-1619
A variety of new coumarin derivatives containing C-4 bridged 2,6-dicyanoanilines (4a-4d) were synthesized via multicomponent one pot approach. These novel sensors were characterized by spectral analysis and a series of pH sensing fluorescence studies were performed, the results indicating that the sensors are highly selective and more effective at various pH. The fluorescence colour changes at different pH could be directly detected by naked eyes. 相似文献
12.
Madarász J. Beregi E. Sztatisz J. Földvári I. Pokol G. 《Journal of Thermal Analysis and Calorimetry》2001,64(3):1059-1065
Sintering processes in the Y2O3–Al2O3–B2 O3 system and its subsystems (Y2O3–B2O3 and Al2 O3–B2O3) have been investigated by using combined DTA and XRD measurements to get a better understanding of solid state chemical
changes resulting in the formation of yttrium aluminum borate (YAl3(BO3)4, YAB) phase and to study the possible role and contribution of various simple borates formed also in the former processes.
Two new exothermic heat effects of YBO3 formation have been detected by DTA in the Y2O3–B2O3 system between 720 and 980°C. In the Al2O3–B2O3 system a new experimental XRD profile of Al4B2O9 was observed. Formation of these borates seems to promote the nucleation of double borate YAB below 1000°C. Conversion of
Al4B2O9 to Al18B4 O33 was observed after a long term (10 h) sintering at 1050°C. Similarly, an increased formation of YAB has been observed as
a product of the sintering reaction between YBO3 and Al18B4O33 at 1150°C. The two latter single borates are found to be identical with the high temperature decomposition products of YAB.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
13.
O. Demolliens F. Weiss R. Madar J.P. Sénateur J.C. Vallier 《Solid State Communications》1985,56(7):589-593
A laboratory process for long Nb3Ge tapes fabrication by chemical vapor deposition (CVD) has been set up. The Nb3Ge tapes which were fabricated offer the possibility of high current and high field operation at 4.2 K since the values of critical current densities, Jc, measured in high magnetic fields at 20T and 4.2K exceed 5 × 104 A cm?2 which is the generally accepted criterion for producing a superconducting magnet. 相似文献
14.
15.
M. Crişan Ana Brăileanu M. Răileanu D. Crişan V. S. Teodorescu R. Bîrjega V. E. Marinescu J. Madarász G. Pokol 《Journal of Thermal Analysis and Calorimetry》2007,88(1):171-176
Pure TiO2
and S-doped TiO2 sol–gel nanopowders were prepared
by controlled hydrolysis-condensation of titanium alkoxides. The influence
of different Ti-alkoxides (tetraethyl-, tetraisopropyl- and tetrabutyl-orthotitanate)
used in obtaining TiO2 porous materials in similar
conditions (water/alkoxide ratio, solvent/alkoxide ratio, pH and temperature
of reaction) has been investigated. The relationship between the synthesis
conditions and the properties of titania nanosized powders, such as thermal
stability, phase composition, crystallinity, morphology and size of particles,
BET surface area and the influence of dopant was investigated. The nature
of the alkyl group strongly influences the main characteristics of the obtained
oxide powders, fact which is pointed out by thermal analysis, X-ray diffraction,
TEM and BET surface area measurements. 相似文献
16.
Kök M. V. Pokol G. Keskin C. Madarász J. Bagci S. 《Journal of Thermal Analysis and Calorimetry》2004,75(3):781-789
In this study the combustion characteristics of crude oils (Karakuę and Beykan) in the presence of a limestone matrix were
determined using the thermogravimetry (TG/DTG). Experiments were performed at a heating rate of 10°C min-1, whereas the air flow rate was kept constant at 10 L h-1 in the temperature range of 20-900°C. In combustion with air, three distinct reaction regions were identified in all crude
oil/limestone mixtures studied known as low temperature oxidation (LTO), fuel deposition (FD) and high temperature oxidation
(HTO). The individual activation energies for each reaction region may be attributed to different reaction mechanisms, but
they do not give any indication of the contribution of each region to the overall reactivity of the crude oils. Depending
on the characteristics, the mean activation energy of samples varied between 50.3 and 55.8 kJ mol-1.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
17.
The notion of a good quotient relation has been introduced as an attempt to generalize the notion of a quotient algebra to
relations on an algebra which are not necessarily congruences. In order to make it possible to prove generalized versions
of 'power isomorphism theorems', the more restrictive notions of very good, Hoare good and Smyth good relation have been
introduced. In this paper we describe the relationships between Hoare good, Smyth good and very good relations. As a consequence,
we prove that every structure preserving relation on an algebra is very good.
Received September 25, 1998; accepted in final form January 14, 1999. 相似文献
18.
Sebestyén Zoltán Jakab Emma Domán Andrea Bokrossy Péter Bertóti Imre Madarász János László Krisztina 《Journal of Thermal Analysis and Calorimetry》2020,141(1):301-312
Journal of Thermal Analysis and Calorimetry - The refrigerator unit based on electrically driven vapor compression technology consumes high energy, associated with high cost and loss of ecosystem.... 相似文献
19.
Saara Riuttamäki Gergely Laczkó Dr. Ádám Madarász Dr. Tamás Földes Dr. Imre Pápai Anton Bannykh Prof. Dr. Petri M. Pihko 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(45):e202201030
We demonstrate herein the capacity of simple carboxylate salts – tetrametylammonium and tetramethylguanidinium pivalate – to act as catalysts in the isomerization of β,γ-unsaturated thioesters to α,β-unsaturated thioesters. The carboxylate catalysts gave reaction rates comparable to those obtained with DBU, but with fewer side reactions. The reaction exhibits a normal secondary kinetic isotope effect (k1H/k1D=1.065±0.026) with a β,γ-deuterated substrate. Computational analysis of the mechanism provides a similar value (k1H/k1D=1.05) with a mechanism where γ-reprotonation of the enolate intermediate is rate determining. 相似文献
20.
Margit Bán Petra Bombicz J. Madarász 《Journal of Thermal Analysis and Calorimetry》2009,95(3):895-901
A new co-crystal of theophylline and phthalic acid with 1:1 molar ratio has been prepared. It crystallises in the monoclinic crystal system, space group P21/c, a=11.5258(9), b=10.1405(6), c=13.9066(12) Å, β=106.827(4)°. The structure of the co-crystal has been revealed by single crystal X-ray diffraction. An infinite helical polymeric chain is formed by intermolecular hydrogen bonds of the two neutral constituents. The hydroxyl group and carbonyl oxygen atom in one of the carboxyl groups of phthalic acid form hydrogen bonds to O6 and to N(7)H atoms of theophylline, respectively, while the other carboxyl OH group of phthalic acid is in hydrogen bond to N9 atom of theophylline by very strong intermolecular interactions proven by 1883 cm?1 centred peak in FTIR spectrum.Thermal degradation of this new supramolecular compound is a two-step process in air. At first phthalic acid (47.4%) released up to 230°C, meanwhile it loses water and transforms into phthalic anhydride. In EGA-MS spectra, the characteristic fragments of water (m/z=17, 18) appear from about 180°C, while absorption bands of phthalic anhydride are shown in EGA-FTIR spectrum at about 210°C. In the second step theophylline begins to sublime, melts at 276°C, and then evaporates up to 315°C with minute residues. 相似文献