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91.
92.
A small library of squamocin analogues has been prepared and screened biologically (cytotoxicity, inhibition of mitochondrial complex I and complex III). To centre diversity on a crucial part of the molecule (i.e., the α,β-unsaturated lactone), an original and reliable lactone opening reaction has been discovered and exploited among other efficient reactions. 相似文献
93.
The temperature of 110° C is quite suitable for drying ammonium chloride, prior to weighing. If the residual platinum from the pyrolysis of ammonium chloroplatinate is weighed it. is necessary to ignite, either between 407° and 538° C, or above 811° C. 相似文献
94.
With the aid of the chevenard thermobalance the authors have traced the pyrolysis curve of the following compounds of rubidium : chloride, perchlorate, sulphate, hexanitritocobaltate, hexachlorostannate, hexachloroplatinate; they have determined the ternperatures of commencement of dissociation of these substances, shown the different behaviour of the neutral and the acid sulphates, and demonstrated that the hexamtritocobaltate (colialtinitrite) cannot be employed for gravimetric analysis and the hexachlorostannate (stannichloride) requires a special method of preparation in order to give accurate results. 相似文献
95.
Giacomo Quaranta Clara Argerich Martin Ruben Ibañez Jean Louis Duval Elias Cueto Francisco Chinesta 《Comptes Rendus Mecanique》2019,347(5):445-454
The present paper analyzes different integration schemes of solid dynamics in the frequency domain involving the so-called Proper Generalized Decomposition – PGD. The last framework assumes for the solution a parametric dependency with respect to frequency. This procedure allowed introducing other parametric dependences related to loading, geometry, and material properties. However, in these cases, affine decompositions are required for an efficient computation of separated representations. A possibility for circumventing such difficulty consists in combining modal and harmonic analysis for defining an hybrid integration scheme. Moreover, such a procedure, as proved in the present work, can be easily generalized to address nonlinear parametric dynamics, as well as to solve problems with non-symmetric stiffness matrices, always operating in the domain of low frequencies. 相似文献
96.
Gilles Chaumat Florent Duval Rémi Blinder Pierre-Alain Bayle Michel Bardet 《Magnetic resonance in chemistry : MRC》2020,58(9):820-829
Conservation treatment of degraded archaeological osseous materials is still an open challenge, since no specific conservation protocol is currently available for restorers or museum curators. This work aims to test the efficiency of two original consolidant solutions in consolidating archaeological material. Archaeological osseous materials remain rare and sparsely available, it is a real drawback for optimization of conservation treatments, therefore in the present work a set of representative samples was chosen. The consolidants tested were a solution of disodium sebacate and a novel polyalcohol (SG1.2) obtained by esterification of 5 succinic diacids with 6 molecules of glycerol at 150°C. Characterization studies of archaeological bones, combining SEM microscopy, IR spectroscopy and high-resolution solid-state 13C NMR investigations, have been carried out to assess the effective permeation of bone by the consolidant solutions and to determine their chemical interactions with the residual components of archaeological bones. Although both water solutions significantly impregnate bone, we show that, the solution with disodium sebacate leads to chemical attack on the mineral component due to preferential precipitation of endogenous calcium by the sebacate ions. Such deleterious behaviour is not observed at all with the SG1,2 chemicals. The added value of the polyalcohol treatment as strengthening agent suitable for archaeological bony materials should be further demonstrated by mechanical and ageing tests. 相似文献
97.
98.
Ming Li Maoyu Shang Hugues F. Duval W. Robert Scheidt 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(10):1206-1207
The precise structure of the title compound, [Fe2O(C44H24Br4N4)2]·2CH2Cl2, is reported. The Fe—N distances are non‐equivalent in pairs because of the asymmetric peripheral substitution; the values are 2.098 Å to the brominated rings and 2.041 Å to the other two rings. The Fe—O bond distance is 1.7583 (4) Å. The molecule has required twofold symmetry so that there is one unique porphyrin macrocycle and one Fe—O bond length in contrast to a previous report on the same species. 相似文献
99.
Vaughn AE Bassil DB Barnes CL Tucker SA Duval PB 《Journal of the American Chemical Society》2006,128(33):10656-10657
Photolysis of the uranyl(VI) Schiff base complex UO2(tBu4-salphen)(THF) (1a) with cobaltocene in THF affords [Cp2Co][UO2(tBu4-salphen)(OH)] (2) in high yield while irradiation in toluene yields no reaction. Electronic emission spectra of 1a reveal a large Stokes' shift in toluene similar to that observed in the free ligand, while in THF the structural rearrangement responsible for this shift is blocked. Instead, the ligand-centered excited state is redirected to the uranyl(VI) center by way of energy transfer, thus generating 2 from the intramolecular activation of a coordinated THF molecule. 相似文献
100.
Kannan S Vaughn AE Weis EM Barnes CL Duval PB 《Journal of the American Chemical Society》2006,128(43):14024-14025
In a dramatic reversal of the normal trend of observed reactivity in uranyl(VI) coordination chemistry, an unprecedented retention of the normally labile equatorial coordination plane accompanies facile and reversible axial oxo/alkoxide exchange during both the photochemical reduction of cationic uranyl(VI) phosphine-oxide complexes with organic substrates and subsequent hydrolysis of the uranium(IV) alkoxide complexes to regenerate the uranyl(VI) starting complex. 相似文献