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991.
Algarra AG Basallote MG Fernández-Trujillo MJ Hernández-Molina R Safont VS 《Chemical communications (Cambridge, England)》2007,(29):3071-3073
Kinetic and DFT studies indicate that the stabilization of a single pyramidal H(3)PO(2) molecule at the M' site of [Mo(3)S(4)M'] clusters requires the participation of two tetrahedral H(3)PO(2) molecules, the role of the second one being assisting tautomerization of a previously coordinated tetrahedral H(3)PO(2). 相似文献
992.
993.
This paper describes the COMAR database for certified reference materials (CRMs). The Web-based version of COMAR is freely
accessible via the Internet. COMAR was established to assist laboratories in finding the CRMs needed. The database is maintained
in a collaboration of the world’s major CRM producers. The planned changes in the database as agreed at the last COMAR council
meeting in Prague in May 2006 are indicated.
相似文献
Thomas SteigerEmail: |
994.
Hernández Molina R Kalinina I Sokolov M Clausen M González Platas J Vicent C Llusar R 《Dalton transactions (Cambridge, England : 2003)》2007,(5):550-557
The reaction of PdCl(2) with [W3S4(H2O)9]4+ in the presence of hypophosphorous acid in 2 M HCl gives cuboidal cluster [W3(PdCl)S4(H2O)9]3+ (1) which undergoes condensation and crystallises from Hpts solutions as edge-linked double cubane cluster [{W3PdS4(H2O)9}2](pts)(8).19H2O (pts = p-toluenesulfonate) (1'). The substitution of Cl- in (1) by different ligands was explored. The Pd atom in the cluster shows an exceptionally high reactivity in the isomerisation of the hydrophosphoryl H2P(O)(OH), HP(O)(OH)2, HPPh(O)(OH) and HPPh2(O) molecules into the corresponding hydroxo tautomers HP(OH)2, P(OH)3, PhP(OH)2 and Ph2P(OH) stabilised by coordination at Pd. The reactions were followed by UV-Vis spectrophotometry and 31P NMR. Formation constants of the 1 : 1 coordination of [M3(PdCl)S4(H2O)9]3+ (M = Mo, W) with HP(OH)2 and As(OH)3 were obtained. The structures of cucurbit[6]uril (C36H36N24O12, CUC[6]) adducts [W3(PdP(OH)3)S4(H2O)8Cl]-(C36H36N24O12)Cl3.12.5H2O (2), and [W3Pd(PhP(OH)2)S4(H2O)7Cl2]2(C36H36N24O12)Cl4.9H2O (3) were determined by single-crystal X-ray diffraction. 相似文献
995.
Chaudhuri P Bill E Wagner R Pieper U Biswas B Weyhermüller T 《Inorganic chemistry》2008,47(13):5549-5551
The redox-active ligand 2-(3,5-dimethoxyanilino)-4,6-di- tert-butylphenol, H 2L (OCH3), results in, as expected, a trisradical complex with a low-spin Co(III) center, [Co (III)(L (OCH3) (*)) 3] ( 1), whereas the Ga(III) center yields a coordinated new hexadentate monoradical ligand, [Ga (III)L (*) 1] ( 2), presumably due to the ligand-derived redox activity involving C-H activation. 相似文献
996.
Sartorel A Carraro M Scorrano G De Zorzi R Geremia S McDaniel ND Bernhard S Bonchio M 《Journal of the American Chemical Society》2008,130(15):5006-5007
Solid state and solution evidence confirms the embedding of an adamantane-like, Ru4O6 fragment by the divacant, gamma-decatungstosilicate ligand. The resulting complex catalyzes water oxidation to oxygen with TON up to 500 and TOF > 450 h-1. 相似文献
997.
Luigi Busetto Fabio Marchetti Rita Mazzoni Stefano Zacchini 《Journal of organometallic chemistry》2008,693(13):2383-2391
The zwitterionic vinyliminium complex [Fe2{μ-η1:η3-C(R′)C(S)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)2] (2a) (R′ = p-Me-C6H4 (Tol), Xyl = 2,6-Me2C6H3) undergoes electrophilic addition at the S atom by HSO3CF3, MeSO3CF3, SiMe3Cl, BrCH2Ph, ICH2CHCH2 affording the complexes [Fe2{μ-η1:η3-C(Tol)C(SX)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)2][Y] (X = H, Y = SO3CF3, 4a; X = Me, Y = SO3CF3, 4b; X = SiMe3, Y = Cl, 4c; X = CH2Ph, Y = Br, 4d; X = CH2CHCH2, Y = I, 4e).Compound 2a and the corresponding vinyliminium complexes 2b and 2c (R′ = CH2OH, 2b; R′ = Me, 2c) react also with etherated BF3 leading to the formation of the corresponding S-adducts [Fe2{μ-η1:η3-C(R′)C(SBF3)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)2] (R′ = Tol, 5a; R′ = CH2OH, 5b; R′ = Me, 5c).In analogous reactions, the zwitterionic vinyliminium complexes undergo S-metalation upon treatment with in situ generated [Fp]+[SO3CF3]− [Fp = Fe(CO)2(Cp)], leading to the formation of [Fe2{μ-η1:η3-C(R′)C(S-Fp)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)2][SO3CF3](R′ = CH2OH, 6a; R′ = Me, 6b; R′ = Bun, 6c).Similarly, zwitterionic vinyliminium containing Se in the place of S also undergo Se-electrophilic addition. Thus, the complexes [Fe2{μ-η1:η3-C(R′)C(SeX)CN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] (R = X = Me, R′ = Tol, 7a; R = Xyl, R′ = Me, X = Fp+, 7b) are obtained upon treatment of the neutral zwitterionic precursors with MeSO3CF3 and [Fp][SO3CF3], respectively.Alkylation at the S or Se atom of the bridging ligand is also accomplished by CH2Cl2, used as solvent, although the reaction is slower compared to more efficient alkylating reagents. The complexes formed by this route are [Fe2{μ-η1:η3-C(R′)C(E-CH2Cl)CN(Me)(R)}(μ-CO)(CO)(Cp)2][X] [E = S, R = Xyl, R′ = Tol, X = Cl, 8a; E = S, R = Xyl, R′ = Me, X = Cl, 8b; E = Se, R = R′ = Me, X = BPh4, 8c].Finally, treatment of the zwitterionic vinyliminium complexes with I2 results in the oxidative coupling with formation of S-S (disulfide) or Se-Se (diselenide) bond. The reactions, performed in the presence of NaBPh4 afford the tetranuclear complexes [Fe2{μ-η1:η3-C(R′)C(E)CN(Me)(R)}(μ-CO)(CO)(Cp)2]2[BPh4]2 [R = Xyl, R′ = CH2OH, E = S, 9a; R = Xyl, R′ = Me, E = S, 9b; R = Xyl, R′ = Bun, E = S, 9c; R = Xyl, R′ = Me, E = Se, 9d; R = Me, R′ = Bun, E = Se, 9e].The molecular structures of 4a, 8c and 9e have been determined by X-ray diffraction studies. 相似文献
998.
Rodríguez-Gonzalo E Domínguez-Alvarez J Ruano-Miguel L Carabias-Martínez R 《Electrophoresis》2008,29(19):4066-4077
CZE was assayed for the separation of carbamate pesticides susceptible to protonation (Pirimicarb, Carbendazim). Different electrophoretic media with high organic contents were explored, adequate separation and resolution being achieved when a BGE based on ACN with acetic acid in the presence of SDS as an ionic additive was used. With a view to increasing the sensitivity of the method, an in-capillary SPE step prior to the electrophoretic separation was developed. We employed a monolithic polymer formed in situ within the capillary as a medium for analyte retention. The synthesized monolithic bed exhibited high porosity and allowed samples to be loaded at flow rates of about 65 microL/min by applying a pressure of 12 bar. A 5-cm length of monolithic sorbent was used to preconcentrate the target analytes from aqueous samples. The analytes retained were eluted from the polymeric phase directly in the separation capillary with the same electrophoretic medium used for their further separation by CZE. For a 15-min preconcentration time, the in-line SPE-CZE approach proposed here permitted the determination of these pesticides in drinking water at a concentration level of 0.1 microg/L, as demanded by current EU legislation. 相似文献
999.
Nanoparticles (Ag, Pd) were prepared by heterogeneous nucleation on the interlayer space of layered montmorillonite and kaolinite
minerals in aquatic dispersion. Interlamellar incorporation of nanoparticles was monitored by X-ray diffraction and verified
by transmission electron microscopy (TEM). After the reduction of adsorbed metal ions, a new Bragg reflection appeared, proving
the formation of nanoparticles in the interlamellar space of clay mineral. Lamellar structure of layered silicates is partly
destroyed by the particle formation. TEM images showed that larger nanoparticles were formed by UV irradiation and hydrazine
hydrate than in the case of reduction by NaBH4. Aqueous solutions of polyvinyl pyrrolidone and clay minerals were used for the stabilization of Pd° nanoparticles. The size
of particles generated on the surface of clay minerals by heterogeneous nucleation increased with increasing metal concentration.
When polymer is added to this system, particle size can be decreased by increasing polymer concentration. In this case, the
particles are stabilized by the concerted action of the support and the macromolecule. The polymers promoted intercalation
of nanoparticles into the clay mineral. In the absence of nanoparticles, the intercalation of polymers was significantly less
extensive. 相似文献
1000.
Chirlene Nascimento Botelho Alan Silva de Menezes Saimon Moraes Silva Lauro Tatsuo Kubota Flávio Santos Damos Rita de Cássia Silva Luz 《Electroanalysis》2023,35(10):e202200572
The COVID-19 pandemic is still a continuing worldwide challenge for public health systems. Early and ultrasensitive identification of the infection is essential for preventing the spread of COVID-19 by pre-symptomatic or asymptomatic individuals, particularly in the community and in-home settings. This work presents a versatile photoelectrochemical (PEC) immunosensor for SARS-CoV-2 detection based on a composite material formed by bismuth vanadate (BiVO4) and strontium titanate (SrTiO3). The PEC platform was denoted as BiVO4/SrTiO3/FTO, and it can be tuned for the detection of either Spike (S) or Nucleocapsid (N) protein by simply altering the antibody immobilized on the platform's surface. Chemical, morphological, and electrochemical characterizations were performed by X-Ray Diffraction, Scanning Electron microscopy, Energy-dispersive X-ray spectroscopy, Electrochemical Impedance Spectroscopy, and Amperometry. With a simple sensing architecture of the PEC platform, it was possible to achieve a linear response range of 0.1 pg mL−1 to 1000 ng mL−1 for S protein and 0.01 pg mL−1 to 1000 ng mL−1 for N protein. The PEC immunosensors presented recovery values for the two SARS-CoV-2 proteins in artificial saliva samples between 97 % and 107.20 % suggesting a good accuracy for the proposed immunosensors. 相似文献