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121.
Rodolfo Nesi Stefano Chimichi Francesco De Sio Roberto Pepino Piero Tedeschi 《Tetrahedron letters》1982,23(42):4397-4400
In contrast with a previous report, permanganate oxidation of the title compound gives the nitroisoxazolone and not 3-methyl-4- nitroisoxazole-5-carboxylic acid ; a reaction pathway, involving the spirocyclisation of the carboxylate , is suggested. 相似文献
122.
123.
124.
Alfredo Camparini Fabio Ponticelli Piero Tedeschi 《Journal of heterocyclic chemistry》1977,14(3):435-438
The synthesis and properties of 4,6-dichloro- (IV), 4-chloro- (XII) and 6-chloro-3-methyl-isoxazolo[5,4-b]pyridine (XI) are described. Depending on the reaction conditions compound IV with hydrazine or methoxide gave mono- or bi-substituted products. The halogen atom at the 4-position was shown to be the more mobile. 相似文献
125.
126.
2-(Methylpyridyl or quinolyl)benz-X-azoles were synthesized by the general reaction between carboxylic acids and o-bifunctional compounds. By reaction of the bases with methyl iodide, a series of salts were recovered which were identified and when possible transformed into the corresponding polymethine dyes. The main spectroscopic features of these compounds are briefly discussed. 相似文献
127.
Piero Macchi 《Annali dell'Universita di Ferrara》1970,15(1):103-112
Riassunto Si studia il concetto di classe di algebre associato ad un insieme di identità regolari nel senso diPlonka [3] mediante un operatore di ?Pseudo prodotto? che viene introdotto.
Lavoro eseguito nell'ambito dell'attività del Consiglio Nazionale per la Matematica del C.N.R. (Contratto n. 115218205174 anno 1970). 相似文献
Summary We introduce an operator ?Pseudo prodotto? to study the concept of class of algebras associated to a set of regular equations (Pzonka [3]).
Lavoro eseguito nell'ambito dell'attività del Consiglio Nazionale per la Matematica del C.N.R. (Contratto n. 115218205174 anno 1970). 相似文献
128.
Giambattista Consiglio Denis A. von Bzard Franco Morandini Piero Pino 《Helvetica chimica acta》1978,61(5):1703-1707
In the hydroformylation of 1,1,1-trideuterio-2-butene with Rh4 (CO)12 the deuterated pentanals formed contain 75% of 5,5,5-trideuterio-pentanal, the rest being substantially 2,2-dideuterio-pentanal. On the contrary, using Co2 (CO)8 as the catalyst precursor, position 1 and 4 are formylated to the same extent. 相似文献
129.
Akbayeva DN Di Vaira M Costantini SS Peruzzini M Stoppioni P 《Dalton transactions (Cambridge, England : 2003)》2006,(2):389-395
Treatment of [CpRu(PPh(3))(2)Cl] 1 with the stoichiometric amount of H(3)PO(2) or H(3)PO(3) in the presence of chloride scavengers (AgCF(3)SO(3) or TlPF(6)) yields compounds of formula [CpRu(PPh(3))(2)(HP(OH)(2))]Y (Y = CF(3)SO(3) 2a or PF(6) 2b) and [CpRu(PPh(3))(2)(P(OH)(3))]Y (Y = CF(3)SO(3) 3aor PF(6) 3b) which contain, respectively, the HP(OH)(2) and P(OH)(3) tautomers of hypophosphorous and phosphorous acids bound to ruthenium through the phosphorus atom. The triflate derivatives 2a and 3a react further with hypophosphorous or phosphorous acids to yield, respectively, the complexes [CpRu(PPh(3))(HP(OH)(2))(2)]CF(3)SO(3) 4 and [CpRu(PPh(3))(P(OH)(3))(2)]CF(3)SO(3) 5 which are formed by substitution of one molecule of the acid for a coordinated triphenylphosphine molecule. The compounds 2 and 3 are quite stable in the solid state and in solutions of common organic solvents, but the hexafluorophosphate derivatives undergo easy transformations in CH(2)Cl(2): the hypophosphorous acid complex 2b yields the compound [CpRu(PPh(3))(2)(HP(OH)(2))]PF(2)O(2) 6, whose difluorophosphate anion originates from hydrolysis of PF(6)(-); the phosphorous acid complex 3b yields the compound [CpRu(PPh(3))(2)(PF(OH)(2))]PF(2)O(2) 7, which is produced by hydrolysis of hexafluorophosphate and substitution of a fluorine for an OH group of the coordinated acid molecule. All the compounds have been characterized by elemental analyses and NMR measurements. The crystal structures of 2a, 3a and 7 have been determined by X-ray diffraction methods. 相似文献
130.
Kretz T Bats JW Losi S Wolf B Lerner HW Lang M Zanello P Wagner M 《Dalton transactions (Cambridge, England : 2003)》2006,(41):4914-4921
Cationic dinuclear Cu(II) complexes 3 and 4 have been prepared using the novel hydroquinone-based imine chelators 2,5-((i)Pr(2)NCH(2)CH(2)N[double bond, length as m-dash]CH)(2)-1,4-(OH)(2)-C(6)H(2) (1) and 2,5-(pyCH(2)CH(2)N[double bond, length as m-dash]CH)(2)-1,4-(OH)(2)-C(6)H(2) (2), respectively (py = 2-pyridyl). X-Ray quality crystals of both complexes were grown from their DMF solutions. The sterically more encumbered compound crystallizes in the form of discrete dinuclear entities with Cu(II) centres in a distorted square-planar ligand environment (one coordination site is occupied by a DMF molecule). The pyridyl derivative 4 features dinuclear hydroquinone-bridged subunits similar to 3. However, the Cu(II) ions are now six-coordinate with two DMF molecules at an axial and an equatorial position of a Jahn-Teller-distorted octahedron. Moreover, the dinuclear subunits are no longer isolated but linked with each other via bridging hydroquinone oxygen atoms which occupy the second apical position of each octahedron. The structure suggests that the magnetic properties of the resulting coordination polymer of 4 could be described by a model valid for dimerized spin chains. As a result of this analysis the antiferromagnetic coupling constants J(1)/k(B) = 9.9 K (intradimer) and J(2)/k(B) = 0.9 K (interdimer) are obtained. Both in 3 and in 4, the hydroquinone --> semiquinone transition of the central bridging unit (E degrees ' = + 0.57 V, 3; E degrees ' = + 0.51 V, 4; DMF; vs. SCE) displays features of chemical reversibility. In the case of , reduction of Cu(II) centres requires a peak potential of E(p) = - 0.42 V. 相似文献