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排序方式: 共有182条查询结果,搜索用时 15 毫秒
81.
This paper presents the development and evaluation of three adaptive network fuzzy inference system (ANFIS) models for a laboratory scale anaerobic digestion system outputs with varied input selection approaches. The aim was the investigation of feasibility of the approach-based-control system for the prediction of effluent quality from a sequential upflow anaerobic sludge bed reactor (UASBR) system that produced a strong nonlinearship between its inputs and outputs. As ANFIS demonstrated its ability to construct any nonlinear function with multiple inputs and outputs in many applications, its estimating performance was investigated for a complex wastewater treatment process at increasing organic loading rates from 1.1 to 5.5 g COD/L d. Approximation of the ANFIS models was validated using correlation coefficient, MAPE and RMSE. ANFIS was successful to model unsteady data for pH and acceptable for COD within anaerobic digestion limits with multiple input structure. The prediction performance showed a high feasibility of the model-based-control system on the anaerobic digester system to produce an effluent amenable for a consecutive aerobic treatment unit. 相似文献
82.
Iron corroles modified with a xanthene scaffold are delivered from easily available starting materials in abbreviated reaction times. These new iron corroles have been spectroscopically examined with particular emphasis on defining the oxidation state of the metal center. Investigation of their electronic structure using (57)Fe Mo?ssbauer spectroscopy in conjunction with density functional theory (DFT) calculations reveals the non-innocence of the corrole ligand. Although these iron corroles contain a formal Fe(IV) center, the deprotonated corrole macrocycle ligand is one electron oxidized. The electronic ground state of these complexes is best described as an intermediate spin S = 3/2 Fe(III) site strongly antiferromagnetically coupled to the S = 1/2 of the monoradical dianion corrole [Fe(III)Cl-corrole(+?)]. We show here that iron corroles as well as xanthene-modified and hangman xanthene iron corroles are redox active and catalyze the disproportionation of hydrogen peroxide via the catalase reaction, and that this activity scales with the oxidation potential. The meso position of corrole macrocycle is susceptible toward nucleophilic attack during catalase turnover. The reactivity of peroxide within the hangman cleft reported here adds to the emerging theme that corroles are good at catalyzing two-electron activation of the oxygen-oxygen bond in a variety of substrates. 相似文献
83.
Madenci D Salonen A Schurtenberger P Pedersen JS Egelhaaf SU 《Physical chemistry chemical physics : PCCP》2011,13(8):3171-3178
Mixed lecithin-bile salt micelles are known to have a cylindrical or worm-like structure. We investigated their shape, length, flexibility and cross-sectional structure using small-angle neutron scattering (SANS). A broad range of sample compositions was studied varying both the total amphiphile concentration and the molar ratio of bile salt (sodium taurochenodeoxycholate, NaTCDC) to lecithin (egg yolk phosphatidylcholine, EYL). The length of the micelles was quantitatively linked to the micellar composition by introducing a simple model. The model takes into account the partitioning of lecithin and bile salt between the bulk, cylindrical parts and the end caps of the micelles. The model also sheds light on the organization of the micelles, both in their cylindrical regions and end caps. 相似文献
84.
In this study, the radiation-induced degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide in aqueous solution was studied under various conditions as a function of irradiation dose in the absence and presence of hydrogen peroxide. The obtained data confirmed that largest yield of radiolytic degradation is obtained in oxidation processes/ionizing radiation, where oxidation is carried out with hydroxyl radicals. For complete degradation of 50?ppm 2,4-D, a required dose was lower in the presence of hydrogen peroxide. The formed major toxic phenolic intermediates were 2,4-dichlorophenol (2,4-DCP) and 4-chlorophenol (4-CP). The chemical analysis of the 2,4-D and the intermediates resulted from the radiolytic degradation were performed using a gas chromatography associated to mass spectrometry (GC?CMS) with ion trap dedector (ITD) and ion chromatography (IC). The formation of chlorophenols in addition to chloride, formaldehyde and carboxylic acids was studied as a function of absorbed dose. 相似文献
85.
In this study, structural alterations in the biomolecular profile of the Cladonia convoluta exposed to lead were investigated considering the potential of lichens in biomonitoring practices. Particularly, qualitative and quantitative changes in the lipids, polysaccharides, proteins, and nucleic acids along with various organic acids in lead-exposed lichen were analytically analyzed using infrared spectroscopy. Moreover, the quantitative changes in chlorophyl and malondialdehyde levels were measured by independent biochemical assays. Chlorophyll content analysis revealed a dose- and time-dependent decrease in chlorophyl content, whereas malondialdehyde content analysis revealed lipid peroxidation as a result of lead exposure. Lead exposure diminished total nucleic acid quantity, which can be an important parameter for the elucidation of heavy metal tolerance mechanisms in lichens. Furthermore, lead exposure increased the quantity of usnic acid, signifying its importance in the lichen-based decontamination of metal polluted areas. 相似文献
86.
Özgür Delice Pınar Kirezli Dilek K. Çiftci 《General Relativity and Gravitation》2013,45(11):2251-2272
We consider a $D$ D dimensional Kasner type diagonal spacetime where metric functions depend only on a single coordinate and electromagnetic field shares the symmetries of spacetime. These solutions can describe static cylindrical or cosmological Einstein–Maxwell vacuum spacetimes. We mainly focus on electrovacuum solutions and four different types of solutions are obtained in which one of them has no four dimensional counterpart. We also consider the properties of the general solution corresponding to the exterior field of a charged line mass and discuss its several properties. Although it resembles the same form with four dimensional one, there is a difference on the range of the solutions for fixed signs of the parameters. General magnetic field vacuum solution are also briefly discussed, which reduces to Bonnor-Melvin magnetic universe for a special choice of the parameters. The Kasner forms of the general solution are also presented for the cylindrical or cosmological cases. 相似文献
87.
Ayhan Usta Mehmet Birey Nursen Sari Aliye Altundas Dilek Nartop 《Journal of Physical Organic Chemistry》2012,25(4):309-313
Ethyl 2‐amino‐4,5,6,7‐tetrahydrobenzo[b]thiophene‐3‐carboxylate [C11H15NO2S] was synthesized by the Gewald method. Its single crystals were grown from an alcohol/ethyl acetate solution at 15 °C and characterized using IR and 1H‐NMR. These single crystals were irradiated for 72 h at 298 K by a 60Co gamma source with a dose speed of 0.864 kGy/h. After irradiation, electron spin resonance (ESR) measurements were carried out to study radiation‐induced radicals in the temperature range from 120 to 450 K. Additionally, for the single crystal, ESR angular dependencies were measured in the xy, xz and yz planes of the substance. This irradiated single crystal was analyzed based on the ESR spectra. Analysis of the spectra revealed that the radical was formed by a C–H bond fission at the carbon end of the substance. It was also observed that the color of the sample changed after irradiation. The hyperfine and g parameters were determined from the experimental spectra. It was inferred from these results that the hyperfine parameters and g value exhibited anisotropic behavior. The average values of these parameters were calculated as follows: g = 2.0088, AH1=H2 = 20.70 G, AH3=H4 = 10.80 G, AHa = 4.59 G, AHb = 3.24 G and, AN = 6.10 G. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
88.
In this work, the dependence of the ethanol production using Saccharomyces cerevisiae 251TP(3-2) on calcium, sodium, and magnesium ion concentration and interaction effects were studied with the use of a statistical
experimental design. The parameters of the ethanol concentration model proposed on the basis of Box–Wilson experimental design
method were evaluated with the use of the experimental data. Comparison of the predicted values from the model with the experimentally
observed values showed that the model is a good fit. From the analysis of model equation, it was seen that sodium ion concentration
has significant main effects on ethanol production, and there is interactive effect only between calcium and magnesium. With
the use of developed model, maximum ethanol concentration of 3.73% (v/v) was obtained when calcium, sodium, and magnesium concentration were 1,515, 930, and 128 mg/L, respectively, for the 10%
sugar concentration in synthetic molasses. 相似文献
89.
In this study, acrylamide (AAm)/aconitic acid (ACA) copolymers were prepared with two different mol% of aconitic acid 4%, 17% and were irradiated with gamma irradiation at different irradiation doses (4 - 25kGy). The percent yield was assigned by gravimetrical method. The effect of irradiation dose, pH and involved amounts of monomers (AAm/ACA) in hydrogels on swelling properties were investigated. The conversion of monomers to hydrogels was 100% at 25kGy. Poly(acrylamide-co-aconitic acid) P(AAm/ACA) hydrogels have been used for the adsorption of some aqueous solutions of dyes such as Methylene Blue (MB) and Safranine-O (S). The hydrogels were swollen in distilled water at pH 3, 5, 7, 8 and in aqueous solutions of dyes. The initial swelling rates of hydrogels are increased by increasing of pH. The effects of concentration of the aqueous solutions of dye and hydrogel composition on the adsorption were investigated. The adsorption is increased and changed depending on the structure of dye and composition of hydrogel. 相似文献