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991.
Farzaneh Manouchehri Bahareh Sadeghi Farhood Najafi Mohammad Hossein Mosslemin 《Journal of the Iranian Chemical Society》2018,15(8):1673-1683
Pentachlorid antimony supported on coconut shell as an efficient and novel catalyst for one-pot synthesis of 2-amino-3-phenylsulfonyl-4-aryl-4H-benzo[h]chromen through three-component condensation of \( \alpha \)- naphtol, arylaldehydes and phenylsulfonyl (acetonitrile). Nanocatalyst pentachloride antimony supported on coconut shell was manufactured and characterized by FT-IR, TGA/DTG, XRD, EDX, FESEM and TEM techniques. The present method has advantages such as high activity, high reaction rate, recoverability of nanocatalyst, a simple experimental procedure, without any using of hazardous organic solvents under green conditions. 相似文献
992.
Mohammad Akbari Mostafa Farajpour Mostafa Aalifar Mohammad Sadat Hosseini 《Natural product research》2018,32(3):322-326
The effects of gamma irradiation (GR) on total phenol, anthocyanin and antioxidant activity were investigated in three different Persian pistachio nuts at doses of 0, 1, 2 and 4 kGy. The antioxidant activity, as determined by FRAP and DPPH methods, revealed a significant increase in the 1–2 kGy dose range. Total phenol content (TPC) revealed a similar pattern or increase in this range. However, when radiation was increased to 4 kGy, TPC in all genotypes decreased. A radiation dose of 1 kGy had no significant effect on anthocyanin content of Kale-Ghouchi (K) and Akbari (A) genotypes, while it significantly increased the anthocyanin content in the Ghazvini (G) genotype. In addition, increasing the radiation to 4 kGy significantly increased the anthocyanin content of K and G genotypes. To conclude, irradiation could increase the phenolic content, anthocyanin and antioxidant activity of pistachio nuts. 相似文献
993.
In the present study, the electrochemical oxidation of quercetin (QUR) was investigated using a graphite paste electrode (GPE) modified with multi-walled carbon nanotube and Lewatit FO36 nanoresin (LFONR-MWCNT/GPE). LFONR-MWCNT/GPE could effectively a sensitive anodic peak at around 0.23 V (vs. SCE) in a 0.10 M phosphate buffer solution. Modified electrode revealed that activated with multiwalled carbon nanotube and LFONR was capable of facilitating electron transfer and increasing surface area. The electrochemical oxidation of QUR was studied using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). Some kinetic parameters for electrochemical oxidation of QUR including total number of electrons (n) and standard heterogeneous rate constant (ks) were also determined. The calibration graph consisted of two linear segments of 1.8–25.0 μM, and 25.0–570.0 μM with a detection limit of 0.213 μM (based on 3Sb). The applicability of the method to juice of peach, red grape, sour cherry and Gincora tablets analysis was also evaluated. 相似文献
994.
In this study, NiS2 nanocubes were successfully synthesized by a novel facile solvothermal method using NiC2O4·2H2O microstructures and used as an electrode for high-performance supercapacitors. The electrochemical properties of the prepared NiS2 electrode were studied using galvanostatic charge–discharge analysis, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) studies. Its maximum specific capacitance was 2077 F g?1 at a constant current density of about 0.65 A g?1. Further, the EIS results confirmed the pseudocapacitive nature of the NiS2 electrode. The experimental results suggested that the NiS2 electro-active material demonstrates excellent electrochemical performance with high specific capacitance, low resistance, and excellent cycling stability. 相似文献
995.
The thermochemistry of the reaction of the microsolvated Na+ such as [Na(H2O) n ; n?=?1?6]+, [Na(NH3) n ; n?=?1?6]+ and [Na(H2O) n (NH3) m ; n?+?m?=?2?6]+ with thymine (Thy), as an example of a reaction in the microcosmic environment, have been studied in this work, theoretically. It was found that the increase of the number of solvent molecules in the structure of microsolvated Na+ is accompanied by the decrease of the standard enthalpy (\(\Delta H_{r}^{^\circ }\)) and Gibbs free (\(\Delta G_{r}^{^\circ }\)) energies of the reaction (Thy?+?[Na(X) n ]+→Thy-Na(X) n + ; X?=?solvent molecule). Also, the calculations showed that the electronic intermolecular interaction (?Eint) between the Thy and microslovated Na+ decreased with the increase of solvent molecules. For the interaction of the [Na(H2O) n ; n?=?4, 5 and 6]+ ions with the Thy, there was the probability of forming of the hydrogen bond between water molecules in the structure of solvated Na+ and the Thy. The gas phase infrared (IR) spectra of the complexes of the microsolvated Na+ with the Thy for different values of n were calculated and compared with each other to follow the change in the frequency of the stretching vibration of the interaction path between the C=O group of the Thy and Na (O…Na) with n. Using the calculated values of \(\Delta G_{r}^{^\circ }\) of the reactions, the mole fractions of the complexes of microsolvated Na+ ions with the Thy were calculated at different humidity. 相似文献
996.
Mahdiyeh Bamdad Hossein Farrokhpour Bijan Najafi Mahmud Ashrafizaadeh 《Structural chemistry》2018,29(6):1745-1751
In this work, the interaction of three Li+-doped polycyclic hydrocarbons (Li+-DPH) with H2 and H2O was calculated to investigate the effect of curvature of substrate on the interaction energy (Eint). For this purpose, the Eint and its decomposed energy components (electrostatic (Eelec), exchange (Eexch), induction (Eind), and dispersion energy (Edisp)) were calculated using DF-SAPT (DFT) methodology for the selected systems (Li+-(3,3) carbon nanotube (Li+-CNT33), Li+-(6,6) carbon nanotube (Li+-CNT66), and Li+-graphene). According to the results, Eint does not change significantly with curvature for the interaction between both H2 and H2O gases and the selected Li+-DPH. Since the variation of the Eint with the curvature of Li+-DPH is not significant, the selection of a planar Li+-DPH is a trustworthy model to develop a general force field for describing the interaction between a Li+-DPH and adsorbed gases. The results reveal that, in the case of the H2, the components Eelect, Eexch, Eind, and Edisp have shown a decreasing trend with Li+-DPH’s curvature decrement. However, for the H2O, Eelect, Eexch, and Eind decrease from the Li+-CNT33 to the Li+-CNT66 while they increase from the Li+-CNT66 to the Li+-graphene. In this case, the Edisp increases with a decrease of the curvature of Li+-DPH. Finally, it can be seen that although the variation of the Eint with the curvature of Li+-DPH is not significant, the variation trend of the interaction energy components and the amount of variation depend on the gas molecule and in some cases are not negligible. 相似文献
997.
Nassim Hemmati Mohammad Hossein Ghazanfari 《Journal of Dispersion Science and Technology》2018,39(5):687-699
In this study, kinetics, equilibrium, and mechanisms of SDBS adsorption onto carbonate rock in presence/absence of alkaline/electrolyte, which is not well discussed in the available literature, is analyzed through batch experiments. Analysis of kinetic data showed that adsorption rate of SDBS onto carbonate is controlled by both boundary layer and intraparticle diffusion, also adsorption kinetics meets pseudo second-order model. The coefficient of kinetic model is a linear function of initial and equilibrium concentrations. The adsorption isotherm experiences four distinct regions, with a rising trend in the first regions until reaching to a maximum after which decreases slightly, as the fourth region, due to micellar exclusion. The prevailing mechanisms in other regions were also discussed. Presence of alkaline changes adsorption mechanisms, so that adsorption isotherm matches well with the Langmuir model, while presence of electrolyte does not change the adsorption mechanisms, but it lessens repulsion between surfactant heads which results in a slight reduction in amount of CMC. A new three-parameter equilibrium model is presented which considers all prevailing mechanisms, and matches properly with obtained experimental data, especially the decreasing trend of fourth region which is very difficult to predict along with other regions using a unique isotherm model. 相似文献
998.
999.
Hossein Mehrabi Farzaneh Alizadeh-Bami Reza Ranjbar-Karimi 《Tetrahedron letters》2018,59(20):1924-1927
An efficient and catalyst-free for the synthesis of 1,2,4,5-tetrasubstituted imidazoles has been developed using a one-pot, two-step reaction of arylamins, benzonitriles, arylglyoxals, and Meldrum’s acid. All the products were obtained in good to excellent yields and their structures were established from their spectroscopic data. 相似文献
1000.
Karami Hossein Hossaini Zinatossadat Sabbaghan Maryam Rostami-Charati Faramarz 《Chemistry of Heterocyclic Compounds》2018,54(11):1040-1044
Chemistry of Heterocyclic Compounds - A convenient one-pot three-component synthesis of indeno[1,2-b]pyrrol-4(1H)-ones has been developed. The reaction of ninhydrin, 1,3-dicarbonyl compounds, and... 相似文献