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1.
Kherroubi Seddik Benkahla Youb Khaled Labsi Nabila Ragui Karim Bensaci Abdelghani Boutra Abdelkader Ouyahia Seif-Eddine Benzema Mahdi 《Journal of Thermal Analysis and Calorimetry》2021,144(3):623-646
Journal of Thermal Analysis and Calorimetry - Through this paper, three-dimensional fluid flow and heat transfer of Al2O3 nanofluid within ventilated enclosures was taken into consideration.... 相似文献
2.
The applicability of differential electrolytic potentiometry as a detection system in flow injection analysis is investigated. A computer-controlled injector which delivers precise volumes of sample solutions in a reproducible manner was developed. Conditions such as current density employed, the concentrations of the solutions used and the flow rate were optimized. Chloride in water was determined by means of this system. The relation between chloride concentration and the measured signal was found to be Nernstian for solutions of concentrations above 6 μg ml−1 chloride. For solutions below this concentration, the relation is linear. 相似文献
3.
Khaled Al-Takhman 《Journal of Pure and Applied Algebra》2002,173(3):245-271
In this article we defined and studied quasi-finite comodules, the cohom functors for coalgebras over rings. Linear functors between categories of comodules are also investigated and it is proved that good enough linear functors are nothing but a cotensor functor. Our main result of this work characterizes equivalences between comodule categories generalizing the Morita-Takeuchi theory to coalgebras over rings. Morita-Takeuchi contexts in our setting is defined and investigated, a correspondence between strict Morita-Takeuchi contexts and equivalences of comodule categories over the involved coalgebras is obtained. Finally, we proved that for coalgebras over QF-rings Takeuchi's representation of the cohom functor is also valid. 相似文献
4.
Khaled A. Aamer Gregory N. Tew 《Journal of polymer science. Part A, Polymer chemistry》2007,45(6):1109-1121
Supramolecular block‐random copolymers containing [Ir(terpy)2]3+ in the side chain were synthesized via postfunctionalization of a P(S‐b‐ACterpy) block copolymer. Absorbance and emission spectra compared to a model compound show that the polymer backbone has a minor effect on the polymer absorbance but produces a larger shift for the phosphorescence signals to higher wavelength. Dynamic light scattering of the metal complex containing copolymer studied in various solvents showed monomodal aggregation with decreasing aggregate size as the solvent dielectric constant increased. The copolymer precursor P(S‐b‐ACterpy) shows multimodal aggregation in different solvents with the major population consisting of single chains. This difference in behavior between the two polymers is attributed to the electrolytic nature of the complex and the amphiphilicity induced by the charged metal complex. Supramolecular copolymers like these will continue to have interesting self‐organizational properties and may find applications in multicomponent systems for photoinduced charge separation processes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1109–1121, 2007 相似文献
5.
It has been observed that a quantum theory need not be Hermitian to have a real spectrum. We study the non-Hermitian relativistic quantum theories for many complex potentials, and obtain the real relativistic energy eigenvalues and corresponding eigenfunctions of a Dirac-charged particle in complex statically and spherically symmetric potentials. Complex Dirac–Eckart, complex Dirac–Rosen–Morse II, complex Dirac–Scarf and complex Dirac–Poschl–Teller potential are investigated. 相似文献
6.
The effects of oscillatory motions that may present at a wall during vibrating conditions are studied on flow induced by natural convection and heat transfer inside an open-end vertical channel. The governing equations are non-dimensionalized and reduced to simpler forms. Analytical solutions are obtained for several limiting cases. The reduced governing equations are solved for various values of the controlling parameters. It is found that mean values of average Nusselt numbers are mainly affected by the Grashof number and the amplitude of the horizontal vibrations. Further, amplitudes of Nusselt numbers at the vibrated wall are decreased as the Grashof number increases for horizontal vibrations while they are increased as amplitudes of vibrations increase. It is also found that the squeezing/vibrational Reynolds number, Grashof number and amplitudes of vibrations have a great influence on the trends of stream lines and isotherms especially at low Grashof numbers. Finally, correlations that summarize the effects of the different controlling parameters are determined on the Nusselt numbers and their amplitudes at relatively low frequency of vibrations. 相似文献
7.
Condensation of 3,5-dinitro-4-chloro-6-methoxy-2-methylquinoline (1) with benzylamine, ethanolamine and/or thioglycolic acid afforded the quinoline derivatives4 a-c. Cyclization of4 a and4 b with alkali and condensation of1 with glycine in sodium carbonate solution furnish 2H-imidazo[4,5-c]quinoline derivatives5 a-c, respectively. Treatment of5 b with benzaldehyde in presence of zinc chloride gave the styryl derivative6. 1 reacted with sodium azide to give the azido derivative4 d, which upon treatment with phenylhydrazine or sodium borohydride yielded the 4-amino derivative4 3. Moreover,1 was treated with phenylhydrazine to give4 f, which cyclized in 10% sodium hydroxide solution to the corresponding v-triazolo[4,5-c]quinoline 3-oxide derivative7. When however4 f was treated with dilute hydrochloric acid, the corresponding phenylpyrazolo[3,4,5-de]quinoline derivative8 was obtained.
Baseninduzierte Cyclisierung einiger Chinoline. Darstellung höherer Stickstoff-Heterocyclen
Zusammenfassung Kondensation von 3,5-Dinitro-4-chlor-6-methoxy-2-methylchinolin (1) mit Benzylamin, Ethanolamin und/oder Thioglycolsäure ergab die Chinolinderivate4 a-c. Cyclisierung von4 a und4 b mit Alkali und Kondensation von1 mit Glycin in Natriumcarbonatlösung lieferte 2H-imidazo[4,5-c]chinolin-Derivate5 a-c. Behandlung von5 b mit Benzaldehyd in Gegenwart von Zinkchlorid ergab das Styrylderivat6. 1 wurde mit Natriumazid zum Azidoderivat4 d umgesetzt, das mit Phenylhydrazin oder Natriumborhydrid zum 4-Aminoderivat4 e weiterreagierte.1 ergab mit Phenylhydrazin4 f, das in 10% NaOH-Lösung zum entsprechenden Triazolo[4,5-c]chinolin-Derivat7 cyclisierte. Aus4 f wurde mit verdünnter Salzsäure das Phenylpyrazolo[3,4,5-de]chinolin8 erhalten.相似文献
8.
Chouhaid Nasr Prashant V. Kamat Surat Hotchandani 《Journal of Electroanalytical Chemistry》1997,420(1-2)
A photoelectrochemical cell with a coupled SnO2|CdSe nanocrystalline semiconductor electrode has been prepared by sequential deposition of SnO2 and CdSe films onto an optically transparent electrode (OTE), and its photoelectrochemical behavior has been studied. The results show that the coupling of CdSe with SnO2 leads to an improvement in the performance of OTE|SnO2|CdSe over OTE|CdSe cells in terms of increased incident photon-to-current conversion efficiency, increased stability and smaller reversal of current. The favorable positioning of the energy bands of SnO2 and CdSe is responsible for the above observations. Various photoelectrochemical parameters of the OTE|SnO2|CdSe cell obtained for an incident light power of 0.31 mW cm−2 at 470nm, are as follows: Isc ≈ 25–30 μA cm−2, Voc ≈ 0.5–0.6 V, ƒƒ = 0.47 and a power conversion efficiency of about 2.25%. 相似文献
9.
Dimethyl 1′,1′-ureylenedi(1-ferrocenecarboxylate) (1) formed during the synthesis of 1-amino, 1′-ferrocenecarboxylic acid shows virtual molecular centrosymmetry. Electronic coupling between the two Fc groups through the ureylene bridge results in both Fc groups being individually oxidizable (ΔE1/2?0.14 V). The possible existence of intermolecular electronic communication has discussed. The oxidation was followed by spectroelectrochemistry. The separation between the two halfwave potentials ΔE1/2=137±5 mV and the comproportionation constant Kc=207. 相似文献
10.
Time-weighted average sampling of volatile and semi-volatile airborne organic compounds by the solid-phase microextraction device 总被引:1,自引:0,他引:1
The ultimate goal of the chemist is to perform sample preparation, and analysis, if possible at the place where a sample is located rather than moving the sample to laboratory, as is common practice in many cases at the present time. This approach eliminates errors and time associated with sample transport and storage and therefore it would result in more accurate, precise and faster analytical data. In addition to portability, two other important features of ideal field sample preparation technique are elimination of solvent use and integration with a sampling step. A method is developed which addresses these requirements for the determination of time-weighted average concentration of gas phase compounds using a solid-phase microextraction device. Quantification of target analytes in air using this method can be carried out without external calibration. The volatile and semi-volatile organic compounds in air diffuse into the fiber coating which is retracted a known distance into its needle housing during the sampling period. The coatings used are poly(dimethylsiloxane) and poly(dimethylsiloxane)-divinylbenzene. The sampling rate at which gas phase analytes load onto the fiber is determined for a wide range of hydrocarbons. There is a good agreement between the theoretical and experimental sampling rates. Sampling time ranges from 1 min to 24 h depending on the coating used and its retraction distance. Effect of the flow-rate on the uptake rate by the fiber is studied. The method is tested in the field and compared with National Institute of Occupational Health and Safety Method 1550. Good agreement between the results is obtained. 相似文献