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71.
Vilsmeier-formylation of the copper(II) complex of chlorin-e6 trimethyl ester (2), under mild conditions, gives selective substitution in the 3-vinyl group. In contrast chlorination of 2 is shown to lead to selective substitution at position 20 of the macrocycle. A similar result is found for [3-ethyl]-isochlorin-e4 dimethyl ester (17) although further reaction leads to more highly chlorinated products which have been isolated and identified. 13C NMR data for some of these compounds and several related chlorin derivatives are reported. In particular, after correction of the literature, many of the quaternary carbon signals of the macrocycle are assigned and substituent effects assessed. Consideration of the shifts of the α-pyrrolic carbons confirms that chlorin and its derivatives exist in a tautomeric form with the two inner H atoms on diagonally opposite pyrrole rings A and C. Such a form allows a satisfactory explanation of the substituent chemical shifts of the formyl group at positions 15 and 20 to be made. 相似文献
72.
M.P. Sánchez-Sánchez J.M. Salas-Peregrín M.A. Romero-Molina A. Mata-Arjona 《Thermochimica Acta》1985,88(2):355-361
The thermodynamic protonation constants of 4-amino-1,6-dihydro-2-methylthio-5-nitroso-6-oxo-pyrimidine (MTH), 4-amino-5-nitroso-6-oxo-1,2,3,6,-tetrahydro-2-thiopyrimidine (TANH) and 2-thioxanthine (TXH) in aqueous media at 25, 30, 40 and 50 ± 0.1°C, have been determined potentiometrically by Bjerrum and Robinson's methods. The ionic strength was maintained constant by using 0.1 M NaNO3 as the supporting electrolyte.The stability constants and thermodynamic functions for Zn(II) and Cd(II) complexes of MTH and TXH, at different ionic strengths and temperatures, have been calculated. 相似文献
73.
The preparation of η-C3H5V(CO)5 from allyl chloride and sodium hexacarbonylvanadate (–I) is reported. Composition, IR and NMR spectra are in accordance with a π-bonded C3H5-moiety; the preparation has been extended to give complexes with substituted allyl groups. Furthermore (1-3-η-2-butenyl)pentacarbonylvanadium can be obtained by the addition of butadiene to HV (CO)6. 相似文献
74.
A.S. Berenblyum A.P. Aeeva L.I. Lakhman I.I. Moiseev 《Journal of organometallic chemistry》1982,234(2):237-248
[(PPh3)3(PPh2)2Pd3Cl] Cl, benzene and aniline hydrochloride were isolated as products of the reactions of (PPh3)2PdCl2]2 or [(PPh3)PdCl2]2 with H2 in organic amines (Am). Similar products were obtained when (Ph3P)2Pd(Ph)Br was treated with H23 Both in amines and aromatic solvents. The reaction between H2 and [(PBu3)PdCl2]2 resulted in the formation of [(PBu3(PBu2)PdCl2 ·. 2 Am The kinetic data for H2 absorption by solutions of palladium(II) complexes are consistent with the heterolytic mechanism of cleavage fo hte HH bond in the coordination sphere of palladium(II); the function of the H+ acceptor being performed by the bases (e.g. Am or Ph). The reaction between the palladium complexes and H2 is autocatalytic. Reduction of the initial PdII complexes leads to lower oxidation state palladium complexes, which catalyse the reduction of PdII complexes. In the coordination sphere of the lower oxidation state palladium complexes, the oxidative addition of PR3 to Pd takes place with formation of compounds containing a Pd-R bond. It is the reaction between these complexes and H2 that yields palladium compounds with PR2 ligands. 相似文献
75.
Two methods for the determination of polyethylene glycols (PEGs) in aqueous solution by precipitation with iodine have been developed. For PEGs with molecular weight 4 x 10(3)-2 x 10(4) the excess of iodine is titrated with thiosulphate, and for PEGs with average m.w. > 2 x 10(4) turbidimetric measurement is used. Both methods are relatively simple and give accurate and reproducible results. 相似文献
76.
A. Van Baalen C.J. Groenenboom H.J. De Liefde Meijer 《Journal of organometallic chemistry》1974,74(2):245-253
The synthesis and the properties of the complexes Cp2TaCl2, Cp2M(allyl), Cp2M(1-methylallyl) and Cp2M(2-methylallyl) with M Nb, Ta are described. The complex Cp2TaCl2 has one unpaired electron per tantalum atom, while the allyl complexes are diamagnetic. The IR and PMR spectra indicate that the allyl group is π-bonded to the metal. The mass spectra of the complexes are discussed; the thermal stability of the Cp2Nb- and Cp2Ta-(allyl) complexes was investigated by differential thermal analysis. The properties of the niobium and tantalum complexes are compared with those of the corresponding titanium complexes. 相似文献
77.
Two new intermetallic compounds have been synthetized and structurally studied by single crystal diffractometric data: Ca7Au3 (oP80, space groupPbca,a = 20.742(8), b = 18.036(8), c = 6.665(2) A?,Z = 8, R = 0.051) and Ca5Au4 (mP18, space groupP21/c, a = 8.028(3), b = 8.019(6), c = 7.727(3) A?, β = 109.16(6)°,Z = 2, R = 0.104). Both atomic arrangements, which represent new structural types, are based on Au-centered Ca trigonal prisms and are geometrically related to the Th7Fe3 and Pu5Rh4 structures. 相似文献
78.
The photophysical characteristics of poly 4(2-acryloxybenzophenone), poly-ABP, and its model compound 4(2-methylpropionyloxy)benzophenone, IBP, have been determined by steady state and pulse methods. In IBP the observed properties are mainly due to the n,π1 triplet of the benzophenonic moiety. In poly-ABP, the formation of singlet excimers competes with the intersystem crossing leading to benzophenonic triplet. The triplet lifetime in polymer is reduced, compared to the model compound. This fact is explained in terms of intramolecular hydrogen abstraction of the triplet. 相似文献
79.
A new reaction of organolithium compounds with phosphonium salts is described; reaction of t-butyllithium with dibenzylaminophosphonium or tetraphenylphosphonium bromides takes place through addition of the t-butyl group on a benzene ring at the position para to the phosphorus atom, the ylid formed reacts in a characteristic Wittig reaction with p-tolylaldehyde. 相似文献
80.
E.P. Schram 《Journal of organometallic chemistry》1976,120(1):C21-C22
The catinic complex trans-[FeCl(CCHPh)(depe)2]+ (depe = bis(diethylphosphino)ethane has been prepared by interaction of trans-[FeCl2(depe)2] with penylacetylene in methanol solution in the presence of NaX (X = BPh4 or PF6. 相似文献