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141.
EuP5O14的配位场理论计算 总被引:1,自引:1,他引:0
EuP_5O_(14)的配位场理论计算 范英芳,杨频,潘大丰(山西大学分子科学研究所,山西省农业科学院情报所,太原,030006)关键词配位场理论,C_(2v)对称场,稀土配合物,EuP_5O_(14)EuP5O14是七十年代发现的一种新型发光材料,它... 相似文献
142.
In a preliminary investigation of the bonding between the sub-lattices of lithium and of graphite in intercalation compounds, molecular orbital calculations are performed on systems of Li atoms v8733t217/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0"> complexed to one or both sides of polynuclear aromatic hydrocarbons. Energy wells calculated reveal possible sites offered to the Li atoms above the aromatic plane to form complexes in both central and edge regions of the molecule. The influence of additional complexed Li atoms on the migratory tendency of a given Li atom is also investigated, and observations made on the effect of the complexed Li atoms on the C-C bonds of the hydrocarbon. 相似文献
143.
The nonkeratinous proteins of wool can be partly or completely dissolved by controlled enzymatic digestion. A comparison between the keratose content of intact wool and that of wool which has been hydrolysed for 96 h with pronase confirms that specifically all the nonkeratinous components are dissolved out of the wool composite by pronase. The influence of microbial infection can be excluded.The residue of wool after the hydrolysis, i. e., a wool low in nonkeratinous proteins, has a higher internal volume, as measured by mercury porosimetry. The centrifugal swelling test shows that these wool samples also have increased hygroscopy. 相似文献
144.
Dierk Knittel V. Suryanarayana Rao 《Monatshefte für Chemie / Chemical Monthly》1986,117(10):1185-1193
Cathodic reduction of v415622m36077432/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-azidochalcones under slightly protic conditions proves to be an excellent method for a selective conversion of the azido function to an amino group without affecting other reducible parts of the molecules. The amino-propenones retain theZ-configuration about the C=C-bond of the starting material, whereas N-acetyl derivatives, obtained under mildly acetylating conditions, are partially isomerised. The low reduction potential of N,N-diacetyl-enamines of this type prevents their direct one step synthesis by electrolysis of azidochalcones under strongly acetylating conditions. The voltammetric behaviour of the azides and their reduction pathway is discussed.
Elektrolytische Untersuchungen an Vinylaziden, 6. Mitt.Elektrolytische Reduktion von Azidochalkonen
Zusammenfassung Die kathodische Reduktion von v415622m36077432/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-Azidopropenon erweist sich als ausgezeichneter Weg, um selektiv zu Enaminen zu gelangen, ohne (wie chemische Reduktionsmittel) auch andere Gruppierungen anzugreifen. Durch die Kontrolle von Protonierungs- bzw. Acetylierungsschritten lassen sich die stabileren N-Acetylamine erhalten. Das niedrig liegende Reduktionspotential der N,N-Diacetylamino-propenone verhindert, daß sie in einer Einstufensynthese bei der Reduktion der Azidochalkone unter stark acylierenden Bedingungen erhältlich sind. Das voltammetrische Verhalten der Azide und ihr Reaktionsweg bei der kathodischen Reduktion werden diskutiert.相似文献
145.
V. N. Bagratashvili A. F. Banishev S. A. Gnedoy V. I. Emelyanov A. N. Jerikhin K. S. Merzljakov V.Ya. Panchenko V. N. Seminogov 《Applied Physics A: Materials Science & Processing》1991,52(6):438-444
The formation of periodic ring structures during laser-induced chemical vapor deposition of metals from metal carbonyl is observed experimentally and described by a theoretical model. 相似文献
146.
A. L. Alexe-Ionescu G. Barbero A. Ignatov E. Miraldi 《Applied Physics A: Materials Science & Processing》1993,56(5):453-455
In this paper two types of surface transitions in nematic liquid crystals are theoretically analyzed with a simple model in which the anchoring energy is the result of both steric and electric interactions. The physical model is proper to explain both the transition temperature experimentally observed in homeotropically aligned nematic liquid crystals, and the change in the mean molecular direction due to the variation of the number of surfactant films, piled on the boundary surfaces with the Langmuir-Blodgett technique.Partially supported by the TEMPUS program 相似文献
147.
E. Larsson 《Fresenius' Journal of Analytical Chemistry》1973,266(3):205-206
Ohne ZusammenfassungKgl. Fysiografiska Sällskapet, Lund, und AB Karlshamns Oljefabriker, Karlshamn, haben die Untersuchung unterstützt, wofür bestens gedankt wird. 相似文献
148.
N. Raouafi M. Freytag P. G. Jones K. Boujlel M. L. BenKhoud 《Structural chemistry》2005,16(2):169-172
The preparation of N-[1-(N,N,Nv2739jw4r19407rr/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">,Nv2739jw4r19407rr/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-tetramethylphosphoramidoyl)-1H-benzimidazol-2-yl]-proponimidic ethyl ester 2 has been achieved by the reaction of N-(1H-benzimidazol-2-yl)-proponimidic acid ethyl ester 1 with N,N,Nv2739jw4r19407rr/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">,Nv2739jw4r19407rr/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-tetramethylchlorophosphoramide. The structure of compound 2 has been determined by X-ray diffraction. The results of (1H, 13C, 31P) NMR, IR, EI-MS spectral data are consistent with those obtained from the X-ray diffraction. The compound crystallizes in the triclinic system, following the EsZ conformation. In the crystal, there are two weak C3–H3v2739jw4r19407rr/xxlarge8901.gif" alt="sdot" align="BASELINE" BORDER="0">s1 and C15–H15v2739jw4r19407rr/xxlarge8901.gif" alt="sdot" align="BASELINE" BORDER="0">sO1 intermolecular hydrogen bonds. 相似文献
149.
We consider conditions under which the distributions of sequences of integer-valued nonnegative strongly additive functions can be approximated by the distributions of sums of independent random variables.__________Translated from Lietuvos Matematikos Rinkinys, Vol. 45, No. 2, pp. 270–281, April–June, 2005. 相似文献
150.
Andrzej Urbańczyk Marek K. Kalinowski 《Monatshefte für Chemie / Chemical Monthly》1990,121(11):879-881
Summary Solvent effects on the electronic absorption spectra of oxovanadium(IV) v1837v31/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-diketonates are discussed. It has been found that positions of the long-wave-length bands can be described in terms of the donor-acceptor concept including the donor numbers and the acceptor numbers.
Lösungsmitteleffekte bei den Elektronenspektren von Oxovanadium(IV)-v1837v31/xhuge946.gif" alt="beta" align="MIDDLE" BORDER="0">-diketonaten. Kommentar zu den Arbeiten von Ebraheem et al. (Kurze Mitt.)
Zusammenfassung Es werden Lösungsmitteleffekte bei den Elektronenspektren von Oxovanadium(IV)-v1837v31/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-diketonaten diskutiert. Dabei wurde gefunden, daß die Lage der langwelligen Banden auf Basis eines Donor-Akzeptor-Modells unter Berücksichtigung der Donor- und Akzeptor-Nummern beschrieben werden kann.相似文献