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Groch Paweł Dziubek Katarzyna Czaja Krystyna Sacher-Majewska Beata 《Journal of Thermal Analysis and Calorimetry》2020,142(4):1447-1456
Journal of Thermal Analysis and Calorimetry - This paper reported thermal properties of ethylene copolymers with di- and tri-alkenylsilsesquioxanes (POSS) synthesized by bis(phenoxy-imine) Ti, Zr,... 相似文献
174.
Beata Skrzypiec Paweł Jodłowski Jerzy W. Mietelski 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(1):771-775
Paper presents results of the plutonium deposition measurements in Gorce Mountains—a small part of western Polish Carpathians, Southern Poland where a national park was established in 1981. Samples were collected in both forest and alp areas. They were analyzed by means of alpha spectrometry preceded by radiochemical treatment. The results for activity concentration are then used to calculate cumulated deposition which range from 45.7 ± 4.3 to 164 ± 19 Bq/m2, what means that it reach in maximum almost three times higher value than UNSCEAR average for global fallout, expected for our latitude. The isotopic activity ratio 238Pu to 239+240Pu indicates global fallout as the main if not the only source of Pu. Nevertheless, presented results for plutonium reveal more uniform Pu deposition pattern in Gorce Mountains than it was observed for 137Cs in earlier study using the same samples. 相似文献
175.
Dorota Tuwalska Damian Trzybiński Artur Sikorski Beata Liberek 《Journal of carbohydrate chemistry》2013,32(6):299-314
Single-crystal x-ray diffraction data for methyl (methyl 3-azido-2,3-dideoxy-β-L-lyxo- and β-D-arabino-hexopyranosid)uronates are presented. Three independent molecules in the asymmetric part of the unit cell of the β-D-arabino stereoisomer were found. These differ slightly in the geometry of the groups bound to the pyranose rings. Conformations and the geometry parameters of all the molecules as well as the planarity of the carbomethoxy group, the linearity of the azido group, and the orientation of the aglycone in the crystal lattice are discussed. Influence of the hybridization, resonance, and crystal packing on the geometry parameters is shown. 相似文献
176.
Gregory B. Kharas Emi Hanawa Jamie Lachenberg Beata Brozek Patricia Miramon Audris C. Mojica 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(6):420-424
Electrophilic trisubstituted ethylene monomers, some ring‐substituted 2‐phenyl‐1,1‐dicyanoethylenes, RC6H4CH?C(CN)2 (where R is 3‐Br, 4‐CH3O; 5‐Br, 2‐CH3O; 4‐Cl, 3‐NO2; 5‐Cl, 2‐NO2; 2‐CN, 3‐CN, 4‐CN, and 4‐(CH3)2N), were synthesized by piperidine catalyzed Knoevenagel condensation of ring‐substituted benzaldehydes and malononitrile, and characterized by CHN elemental analysis, IR, 1H‐ and 13C‐NMR. Novel copolymers of the ethylenes and vinyl acetate were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H and 13C‐NMR, GPC, DSC, and TGA. High T g of the copolymers, in comparison with that of polyvinyl acetate, indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 190–800°C range. 相似文献
177.
Roman Mazurkiewicz Beata Fryczkowska Rafał Gabański Roman Luboradzki Andrzej Włochowicz Wojciech Mól 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2589-2598
A reaction of g -carbonyl phosphorus ylides with imidoyl halides gives hitherto unknown g -( N -acylamino)vinylphosphonium salts. The same product can be obtained using the N-monosubtituted amide/Ph 3 PBr 2 /Et 3 N system instead of imidoyl halide. The key step of the reaction probably involves an intramolecular [1,3] O-to-N migration of the vinyl group, converting the primary O -imidoylation product into g -( N -acylamino)vinylphosphonium salt. 相似文献
178.
Joanna Pałdyna Beata Krasnodębska‐Ostręga Monika Sadowska Justyna Gołębiewska 《Electroanalysis》2013,25(8):1926-1932
A sensitive voltammetric method (DPASV) was developed for the determination of Tl(I) and Tl(III) in plant extracts. To limit the influence of the organic matrix on the measurements, UV irradiation and addition of Amberlite XAD‐7 resin was studied. The application of 0.5 g of the resin allowed defining thallium speciation in 10.0 mL of a solution containing 0.20 mL of Sinapis alba extract. The quantification limit of 0.5 ng mL?1 Tl(I) was found for only 10 min of preconcentration, and is low enough to allow dilution of the sample before thallium determination. The procedure was validated using the recovery study and intermethod comparison with HPLC ICP MS. 相似文献
179.
Beata Paczosa-Bator 《Mikrochimica acta》2014,181(9-10):1093-1099
The potentiometric properties of all-solid-state nitrate-selective electrodes based on plasticized PVC and containing different types of nanosized carbon black were investigated. The use of a carbon black interlayer is shown to significantly improve the potentiometric response. The electrodes display a close-to-Nernstian slope in the range from 10?1 to 10?6 M, highly stable potentials and low membrane resistance. However, different analytical features were found depending on the type of carbon black used. The best long-term potential stability was observed for the electrode with Printex XE2-B carbon black that has a relatively high BET surface area (1000 m2?·?g?1) and an average particle size of 30 nm. Nevertheless, the electrodes with the Vulcan XC-72 (BET surface: 240 m2?·?g?1; average size: 55 nm) showed the most repeatable and reproducible standard potential. The lowest detection limit for nitrate (2.5·10?7 M) is observed for an electrode containing Vulcan XC-72. Figure
The comparison of the potentiometric behavior of all-solid state ion-selective electrodes with the different types of the furnace carbon black is presented by employing the nitrate-selective membrane. The electrodes display a close-to-Nernstian slope, highly stable potentials and low membrane resistance 相似文献
180.
A one-pot process leading to complex aromatic heterocyclic compounds has been designed. Kröhnke methodology has been used to synthesize indolizines bearing an aldimino-substituent at position 1. Further reaction of these compounds with 1,2-diketones and ammonium acetate led to tetra-substituted imidazoles in 5–28% overall yield. The resulting compounds display strong absorption of UV radiation and emission of a blue light accompanied with large Stokes shifts. Replacing the aryl substituents with thiophene at position 3 of the indolizine and position 2 of the imidazole produce a further red shift of the absorption (vs products with substituted benzene rings) as a result of a more planar conformation in the ground state. 相似文献