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411.
Sonia de Almeida Giseli Bernabé Marisa S. Crespi Clóvis A. Ribeiro Evaneide Nascimento Lima 《Journal of Thermal Analysis and Calorimetry》2011,105(2):461-465
The organic fraction of urban solid residues disposed of in sanitary landfills during the decomposition yields biogas and
leachate, which are sources of pollution. Leachate is a resultant liquid from the decomposition of substances contained in
solid residues and it contains in its composition organic and inorganic substances. Literature shows an increase in the use
of thermoanalytical techniques to study the samples with environmental interest, this way thermogravimetry is used in this
research. Thermogravimetric studies (TG curves) carried out on leachate and residues shows similarities in the thermal behavior,
although presenting complex composition. Residue samples were collected from landfills, composting plants, sewage treatment
stations, leachate, which after treatment, were submitted for thermal analysis. Kinetic parameters were determined using the
Flynn–Wall–Ozawa method. In this case they show little divergence between the kinetic parameter that can be attributed to
different decomposition reaction and presence of organic compounds in different phases of the decomposition with structures
modified during degradation process and also due to experimental conditions of analysis. 相似文献
412.
Additive manufacturing or 3D printing is the advanced method of manufacturing monolithic adsorbent materials. Unlike beads or pellets, 3D monolithic adsorbents possess the advantages of widespread structural varieties, low heat and mass transfer resistance, and low channeling of fluids. Despite a large volume of research on 3D printing of adsorbents having been reported, such studies on porous carbons are highly limited. In this work, we have reported direct ink 3D printing of porous carbon; the ink consisted of commercial activated carbon, a gel of poly(4-vinylphenol) and Pluronic F127 as plasticizer, and bentonite as the binder. The 3D printing was performed in a commercial 3D printer that has been extensively modified in the lab. Upon 3D printing and carbonization, the resultant 3D printed porous carbon demonstrated a stable structure with a BET area of 400 m2/g and a total pore volume of 0.27 cm3/g. The isotherms of six pure-component gases, CO2, CH4, C2H6, N2, CO, and H2, were measured on this carbon monolith at 298 K and pressure up to 1 bar. The selectivity of four gas pairs, C2H6/CH4, CH4/N2, CO/H2, and CO2/N2, was calculated by Ideally Adsorbed Solution Theory (IAST) and reported. Ten continuous cycles of adsorption and desorption of CO2 on this carbon confirmed no loss of working capacity of the adsorbent. 相似文献
413.
P.Michelin Lausarot M. Turini G.A. Vaglio M. Valle A. Tiripicchio M.Tiripicchio Camellini P. Gariboldi 《Journal of organometallic chemistry》1984,273(2):239-246
The reaction of PhCN with Ru3 (CO)12 in the presence of acetic acid gives H4Ru4(CO)12, (I), (μ-H)Ru3(CO)10(μ-NCHPh) (II) and (μ-H)Ru3(CO)10(μ-NH-CH2Ph) (III) as the main products. Reaction under 110 atm of H2 gives more III and also gives benzylamine. Replacement of acetic acid by H2 at atmospheric pressure gives only II. When H4Ru4CO)12 reacts with PhCN alone or in the presence of NaOH, II is formed as the only product.The structures of II and III have been fully elucidated by X-ray methods. The nitrogen atom of the NCHPh ligand in II and that of the NHCH2Ph ligand in III, interact with the isosceles-triangular metal cluster, symmetrically bridging the shortest Ru(1)-Ru(2) edge. A hydride ligand in both II and III bridges the same Ru(1)-Ru(2) edge of the cluster. Under mild conditions acetic acid is an essential requirement for the activation of Ru3(CO)12 for reaction with PhCN to give III, which cannot be obtained under these conditions from II. 相似文献
414.
Vívian Aparecida Ricardo Teixeira Ernesto Clóvis Augusto Ribeiro Ossamu Hojo Fernando Luis Fertonani Marisa Spirandeli Crespi 《Journal of Thermal Analysis and Calorimetry》2009,97(2):653-656
Bagasse samples from four different sugarcane were directly collected as the residues of milling in a processing plant. The
samples were dried at 105 °C, compressed to small granules and then their TG/DTA and DSC curves in synthetic air were recorded.
Similar thermogravimetric curves were obtained for the different samples and they exhibited four mass loss steps. However,
the analysis of the exotherm DSC peaks showed that the oxidation of the organic matter resulted different enthalpy values
(ΔH/kJ g−1). 相似文献
415.
Cabeza M Flores E Heuze I Sánchez M Bratoeff E Ramírez E Francolugo VA 《Chemical & pharmaceutical bulletin》2004,52(5):535-539
The in vitro antiandrogenic activity of four new progesterone derivatives: 4, 5, 6 and 7 (8 is a known compound) was determined. These compounds were evaluated as 5alpha-reductase inhibitors as well as by their capacity to bind to the androgen receptor in gonadectomized hamster prostate. The IC(50) value was determined using increasing concentrations of 4, 5, 6, 7 and 8 in the presence of [(3)H]T and the microsomal fraction of the hamster prostate containing the 5alpha-reductase enzyme. In this paper we also demonstrated the effect of increasing concentrations of the novel steroids upon [(3)H]DHT binding to the androgen receptors from hamster prostate which produces competition for the androgen receptor sites. The in vitro studies showed that steroids 4, 5, 6, 7 and 8 had an inhibitory activity for the 5alpha-reductase with IC(50) of: 4 (0.17 microM), 5 (0.19 microM), 6 (1 microM), 7 (4.2 microM), and 8 (2.7 microM). On the other hand, the IC(50) value for compounds 4, 5, 6, 7, 8 and DHT showed the following order of affinity for the androgen receptor: 6>7>5>DHT. Surprisingly compounds 4 and 8 did not bind to the androgen receptor. The overall data indicate that all synthesized compounds are inhibitors for the enzyme 5alpha-reductase present in the hamster prostate. In contrast, compounds 5, 6 and 7, which have a cyclohexyl group in the side chain showed a high affinity for the androgen receptor. 相似文献
416.
By reacting thiosemicarbazides substituted on the aminic nitrogen with 5-formyluracil, several new 5-formyluracil thiosemicarbazones (H3ut) derivatives were synthesised and characterized. These ligands, treated with copper chloride and nitrate, afforded two different kinds of compounds. In the complexes derived from copper chloride the metal atom is pentacoordinated, being surrounded by the neutral ligand binding through SNO donor atoms and by two chlorines, while the nitrate derivatives consist of monocations and nitrate anions. The copper coordination (4 + 2) involves the SNO ligand atoms, two water oxygens and an oxygen atom of a monodentate nitrate group. On varying the substituents on the thiosemicarbazidic moiety, remarkable modifications of the coordination geometry are not observed for the complexes with the same counterion. For all the compounds, interactions with DNA (calf thymus) were studied using UV–Vis spectroscopy; the nuclease activity was verified on plasmid DNA pBR 322 by electrophoresis. 相似文献
417.
Pattacini R Barbieri L Stercoli A Cauzzi D Graiff C Lanfranchi M Tiripicchio A Elviri L 《Journal of the American Chemical Society》2006,128(3):866-876
Reaction of RNHC(S)PPh2NPPh2C(S)NR (HRSNS; R = Me, Et) with M(I) (M = Cu, Ag, Au) salts afforded zwitterionic complexes of the general formula [M(RSNS)] (M = Cu, Ag, Au). The ligand was found in the solid state in S,S-kappa2 and S,N,S-kappa3 coordination fashions. [Cu(RSNS)] and [Ag(RSNS)] can be used as metalloligand building blocks for the assembly of pentanuclear multizwitterionic Cu5, Cu3Ag2 and Ag5 core clusters of the general formula [M'2{M(RSNS)}3]2+ (M = Cu, M' = Cu, Ag; M = M' = Ag) upon reaction with suitable M' salts. The crystal structures of the most significant compounds are reported herein. Compound [Ag2{Ag(RSNS)}2(OTf)2] was also isolated and structurally characterized, representing a model for the intermediate species of the aforementioned assembly. 相似文献
418.
419.
420.
Jefferson L. M. A. Gomes Nlio Henderson Marisa C. G. Rocha 《Macromolecular theory and simulations》2001,10(9):816-826
This work presents the vapor–liquid equilibrium calculations in an isothermal flash, applied to polymer solutions, using the Peng–Robinson cubic equation of state modified by Stryjek–Vera, and the mixing rule introduced by Wong–Sandler. This rule allows combining the rigid lattice thermodynamic model of Flory–Huggins to the Peng–Robinson–Stryjek–Vera equation of state. As the Gibbs free energy must be minimum in the equilibrium state, a stochastic optimization method, the simulated annealing algorithm, was used to find out the extreme of this thermodynamic potential. 相似文献