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61.
Summary Kinetics of formation of [PdCl4]2– from [Pd(ox)2]2– and [Pd(mal)2]2– has been studies in aqueous acid media in the presence of an excess of chloride ion by stopped-flow spectrophotometry. Both the complexes undergo the transformation in two well separated consecutive steps. In 0.02–0.05 M acid with 0.2 M Cl–, Pd(AA)2– dissociates leading to the formation of [Pd(AA)Cl2]2– (where AA =ox2– or mal2–), which in 0.1–0.6 M acid and 1 M Cl– forms [PdCl4]2– in a relatively slow step. For both steps kabs=k0+k2[H+][Cl–]. Activation parameters corresponding to k0 and k2 have been determined. Results indicate that [Pd(mal)2]2– is much more labile to substitution than [Pd(ox)2]2– and for both the lability is far greater than that of [Pd(bigH)2]2+ and [Pt(ox)2]2– reported earlier. 相似文献
62.
P. Anna E. Zimonyi A. Márton A. Szép Sz. Matkó S. Keszei Gy. Bertalan Gy. Marosi 《Macromolecular Symposia》2003,202(1):245-254
Polypropylene-based composites were prepared containing non-treated and various treated cotton fibre and wood flakes. A correlation was observed among the fibre treatment and compounding parameters, mechanical and discoloration properties. The structural changes in fibres were demonstrated by Raman spectroscopic and DSC measurements. The possibility for forming cellulose fibre containing flame retardant composites was also investigated. The efficiency of various treatments on compounding, discoloration and mechanical properties enhance in the following order: no treatment < non ionic surfactant < reactive silicone segment containing non ionic surfactant < special silylation treatment. The best results obtained with the special silylation treatment were explained with the more organophilic character and by the thermal stability of the treated fibres. Cellulose fibre as a polyol-charring component and ammonium-polyphosphate together constitute a high performance intumescent flame retardant system in the PP matrix. 相似文献
63.
Sándor Keszei Péter Anna Györgi Marosi Andrea Márton Györgi Bertalan Ferenc Valló 《Macromolecular Symposia》2003,202(1):235-244
Flame retarded polyethylene compounds were prepared using a series of aluminium hydroxide of different particle size applying a milling processes and special precipitation technologies. The processability and flame retardant efficiency of the flame retarded systems were compared. The effects of various surface modifications were analysed in case of one selected type of aluminium hydroxide. A silicone terminated reactive surfactant promoted not only the processability but also the flame retardant efficiency. Noise damping sheets were prepared by simultaneous application of aluminium hydroxide and barium sulphate in an elastomer blend matrix. V0 flame retardant grade could be achieved this way accompanied with improvement in the acoustic properties and maintenance of the mechanical properties. 相似文献
64.
Suggestions for the mechanism of electron solvation in methanol during the last three decades were mostly based on limited time resolution measurements, or indirect observations. The two-channel solvation scheme proposed by Lewis and Jonah (1986) based on indirect observations in electron scavenging experiments is checked here to see if it is in accordance with recent sub-picosecond pump-and-probe laser experimental results. We confirm the applicability of this solvation mechanism and calculate quantitative kinetic and spectral parameters involved. 相似文献
65.
Shyamapada Shit Soma Sen Samiran Mitra David L. Hughes 《Transition Metal Chemistry》2009,34(3):269-274
Two new square-planar Ni(II) complexes, [NiL1(NCS)] (1) and [NiL2(N3)] (2) have been synthesized with the unsymmetrical tridentate Schiff base ligands [(CH3)2NCH2CH2N=C(CH3)CH=C(OH)(C6H5)], L
1
H, derived from benzoylacetone and 2-dimethylaminoethylamine and [(CH3CH2)2NCH2CH2N=C(CH3)CH=C(OH)(C6H5)], L
2
H, derived from benzoylacetone and 2-diethylaminoethylamine, respectively. The complexes have been characterized by elemental
analysis, FT-IR, UV-Vis spectroscopy, electrochemical and thermal methods (where applicable). Structures have been established
by the single-crystal X-ray diffraction technique which reveals the discrete nature of the complexes in which the metal centers
adopt a distorted square planar geometry. Coordination environments of the metal ions in the complexes are satisfied with
two different unsymmetrical Schiff base ligands having similar N2O donor sets and a terminal pseudohalide anion (thiocyanate for 1 and azide for 2). 相似文献
66.
In this study, bisphenol A polyetherimide was sulfonated to various degrees (22, 48, and 62%) by trimethylsilylchlorosulfonate (TMSCS). Novel anhydrous proton conducting polyelectrolytes were prepared by the incorporation of 1H‐1,2,4‐triazole (Taz) as proton solvent in sulfonated polyetherimide (SPEI) matrix. The conductivity reached about 2 × 10–3 S/cm at 80 °C and 10–2 S/cm at 140 °C. The temperature dependence proton conductivity of the polyelectrolytes followed Arrhenius equation. The conductivity improved considerably at a temperature close to the triazole melting temperature in SPEI(X)H matrix. It was proposed that the high mobility of the triazolium ions (vehicle diffusion), in addition to structure diffusion, contribute to the high conductivity of these proton conducting electrolytes above the melting temperature of triazole. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 2178–2187, 2009 相似文献
67.
T. Soma 《Solid State Communications》1980,34(5):375-378
The thermal expansion of GaP is estimated theoretically as a function of temperature using the experimental pressure dependence of elastic stiffness constants and phonon frequencies. The numerical values of the linear expansion coefficient and the Grüneisen constant do not become negative at low temperatures, contrary to other tetrahedrally bonded covalent solids. This positive thermal expansion of GaP at low temperatures is closely connected with the small values of the transverse acoustical mode Grüneisen parameter and with the large value of the metallic phase transition pressure from the linear correlation obtained by Weinstein. 相似文献
68.
69.
70.
Does there exist any equivalence between the notions of inconsistency and consequence in paraconsistent logics as is present
in the classical two valued logic? This is the key issue of this paper. Starting with a language where negation (?{\neg}) is the only connective, two sets of axioms for consequence and inconsistency of paraconsistent logics are presented. During
this study two points have come out. The first one is that the notion of inconsistency of paraconsistent logics turns out
to be a formula-dependent notion and the second one is that the characterization (i.e. equivalence) appears to be pertinent
to a class of paraconsistent logics which have double negation property. 相似文献