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71.
Aleksandra Rybak Gabriela Dudek Monika Krasowska Anna Strzelewicz Zbigniew J. Grzywna Petr Sysel 《Chemical Papers》2014,68(10):1332-1340
Ethylcellulose (EC) or linear polyimide (LPI) and magnetic neodymium powder particles MQP-14-12 were used for the preparation of inorganic-organic hybrid membranes. For all the membranes, N2, O2 and air permeability were examined. Mass transport coefficients were determined using the Time Lag System based on dynamic experiments in a constant pressure system. The results showed that the membrane permeation properties were improved by the addition of magnetic neodymium particles to the polymer matrix. The magnetic ethylcellulose and polyimide membranes exhibited higher gas permeability and diffusivity, while their permeability selectivity and solubility were either unchanged or slightly increased. Polyimide mixed matrix membranes were characterised by a higher thermal and mechanical stability, larger filler loading, better magnetic properties and reasonable selectivity in the air separation. 相似文献
72.
Vadim V. Ilyushin Zbigniew Kisiel Heinrich Mäder 《Journal of Molecular Spectroscopy》2010,259(1):26-12194
A new program is described for fitting rotation-torsion energy levels in molecules like toluene, in which the frame (C6H5) has C2v symmetry and the methyl top has C3v symmetry, i.e., for molecules where the internal rotation barrier is expanded in cos6nα, where α is the internal rotation angle and n = 1,2,…. The program is based on the theoretical framework developed by Sørensen and Pedersen in their application of the Longuet-Higgins permutation-inversion group G12 to the microwave spectrum of CH3NO2. It is specifically designed for sixfold barrier molecules, and allows the user to select almost any symmetry-allowed torsion-rotation term for inclusion in the fitting Hamiltonian. This program leads to a very successful fit of transitions in the microwave spectrum of toluene characterized by J ? 30, Ka ? 12, and by the free-rotor quantum number ∣m∣ ? 3. In these fits we included both published and rather extensive unpublished new measurements, for which fits using other torsion-rotation programs have not been very successful. The fit presented here uses 28 parameters to give an overall standard deviation of 7.4 kHz for 372 line frequencies, and results in a much improved value for the sixfold barrier for toluene, V6 = 13.832068(3) cal mol−1. 相似文献
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Two types of biomolecules were tested in the comparison of usefulness of two ways of formation of the intermediate layers at electrodes: a 20‐nucleotide DNA sequence and glucose oxidase. Chronocoulometric, amperometric, electrochemical impedance and PM‐IRRAS experiments proved that the layers obtained by electroreduction of diazonium salts are much more stable and more efficient in the accumulation of biomolecules compared to layers obtained by self‐assembling of appropriate thiols. 相似文献
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78.
Zbigniew GrobelnyAndrzej Stolarzewicz Barbara Morejko-Bu?Adalbert Maercker 《Journal of organometallic chemistry》2002,660(1):6-13
The linear ether bond was exclusively cleaved in benzyl glycidyl ether and triphenylmethyl glycidyl ether under the influence of K−, K+(15-crown-5)2 (1), whereas the strongly strained three-membered oxacyclic ring remained undisturbed. Potassium glycidoxide and benzylpotassium were found as the primary reaction products of benzyl glycidyl ether with 1. Subsequently, benzylpotassium reacted with benzyl glycidyl ether giving the next potassium glycidoxide molecule and bibenzyl. Benzyl phenyl ether was used as a model compound to explain the mechanism of bibenzyl formation. The reaction of triphenylmethyl glycidyl ether with 1 resulted in potassium glycidoxide and stable triphenylmethylpotassium. After treating with a quenching agent a new glycidyl ether or glycidyl ester was obtained from potassium glycidoxide. These results were found when the reaction occurred at the excess of glycidyl ether. In another case, i.e. at the excess of 1 further reactions took place with the participation of potassium anions and various new compounds were observed in the reaction mixture after benzylation or methylation. Thus, the method of substrates delivery influences the course of studied processes in a decisive way. 相似文献
79.
Zusammenfassung Die Bestimmungsmethode für Mikromengen elementaren, in Sulfiden enthaltenen Schwefels mit Natriumazid und Jod wurde modifiziert. Der Analyse geht die Aufspaltung des S8-Ringes voraus, die man dank der nukleophilen Wirkung von N3
– in DMF-Lösung erreicht. Diese Methode wurde auf die Bestimmung des Schwefels in Indium-, Blei-, Antimon- und Wismutsulfid angewandt. Sie ist einfach und empfindlich. Ihre Fehlergrenze liegt bei ± 4%.
Determination of microamounts of sulfur after cleavage of the S8 king in indium, lead, antimony and bismuth sulfides by means of an induced reaction of sodium azide with iodine
Summary The determination of microamounts of elemental sulfur contained in sulfides using sodium azide and iodine was modified. The analysis was preceded by cleavage of the S8 ring, which is achieved by virtue of the nucleophilic action of N3 – in DMF solution. This method was applied to the determination of sulfur in indium, lead, antimony and bismuth sulfides. It is simple and sensitive. Its limit of error is ±4%.相似文献
80.
Marek L. Główka Zbigniew J. Kamiński Gastone Gilli Valerio Bertolasi 《Journal of chemical crystallography》1986,16(4):569-576
C14H17NO4 crystallizes in the monoclinic space groupP21/n (Z=4) witha=10.208(2),b=10.888(2),c=11.909(2) Å, and=90.89(2)°. The structure was solved by direct methods and refined by full-matrix LSQ to anR factor of 0.036. The 4-oxo-1,3-dioxane ring is in a slightly distorted O(1)-sofa conformation flattened at the C(4) end with the 5-isopropyl substituent in a pseudoaxial position and planar lactone group. The molecules form dimers by means of intermolecular N-HO(4) hydrogen bonds of 3.091(2) Å. The1H NMR spectrum of the title compound shows unusual features. 相似文献