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排序方式: 共有862条查询结果,搜索用时 15 毫秒
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Hossein Soltani Hadi Beitollahi Abdol-Hamid Hatefi-Mehrjardi Somayeh Tajik Masoud Torkzadeh Mahani 《Ionics》2014,20(10):1481-1488
A carbon paste electrode modified with benzoylferrocene (BF) and carbon nanotubes (CNTs) have been applied to the electrocatalytic oxidation of homocysteine which reduced the overpotential by about 165 mV with an obvious increase in the current response. The transfer coefficient (α) for the electrocatalytic oxidation of homocysteine and diffusion coefficient of this substance under the experimental conditions were also investigated. In a phosphate buffer solution (PBS) of pH 7.0, the oxidation current increased linearly with two concentration intervals of homocysteine; one is 0.1 to 10.0 μM, and the other is 10.0 to 80.0 μM. The detection limit (3σ) obtained by square wave voltammetry (SWV) was 50.0 nM. The proposed method was successfully applied to the determination of homocysteine in real samples. 相似文献
794.
Masoud Bezi Javan Samaneh Ebrahimi 《Applied Physics A: Materials Science & Processing》2014,114(2):529-536
We studied the structural, electronic, and magnetic properties of C59Ir, C58Ir2, and C69Ir heterofullerenes by employing density functional theory and the generalized gradient approximation. There are six distinct isomers of C58Ir2 with high probability to form stable structures. The most stable structure of the C69Ir heterofullerene was investigated by comparing the iridium binding energies at the different atomic sites on the D5h C70 cage. There is a strong hybridization between the atomic orbitals of the iridium and those of the carbon atoms, leading to the spin quenching of the iridium atoms in the most stable C58Ir2 heterofullerene. 相似文献
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Alireza Bazmandegan-Shamili Ali Mohammad Haji Shabani Shayessteh Dadfarnia Mahboubeh Saeidi Masoud Rohani Moghadam 《Journal of the Iranian Chemical Society》2017,14(4):843-851
A vortex-assisted dispersive liquid–liquid microextraction method in combination with UV–Vis spectrophotometry was developed for the simultaneous extraction and determination of iron species. In this method, Fe2+ and Fe3+ were complexed with pyridine-2-amidoxime, neutralized through ion pair formation with sodium dodecyl sulfate, and extracted into the fine droplets of chloroform. After centrifugation, the absorbance of the extracted complexes was recorded in the wavelength range of 360–700 nm. The parameters affecting the extraction efficiency such as the pH, the type and volume of the extraction solvent, ligand concentration, and sample volume were optimized. The individual iron species was then determined by means of the orthogonal signal correction–generalized partial least squares method. Under the optimized conditions, the calibration curves were linear over the range of 2.0–100 and 3.0–200 µg L?1 with detection limits of 0.4 µg L?1 for Fe2+ and 0.8 µg L?1 for Fe3+, respectively. The relative standard deviations for intra- and inter-day assays (n = 5) were 2.3 and 4.0 for Fe2+ at 50 µg L?1 and 2.7 and 4.3 for Fe3+ at 30 µg L?1, respectively. The enhancement factors of 77 and 69 were achieved for Fe2+ and Fe3+, respectively. The proposed method was successfully applied to the determination of iron species in water samples. 相似文献
798.
Masoud?Taleb Roman?Ivanov Sergei?Bereznev Sayed?Habib?Kazemi Irina?HussainovaEmail authorView authors OrcID profile 《Mikrochimica acta》2017,184(12):4603-4610
The authors describe the fabrication of an interconnected edge-exposed graphene nanostructure via chemical vapor deposition (CVD) of foliated graphene onto a network of alumina nanofibers. The fibers such obtained are shown to enable ultra-sensitive voltammetric determination of dopamine (DA), uric acid (UA) and ascorbic acid (AA). The electrode displays powerful and persistent electro oxidative behavior and excellent electron transport properties. Cyclic voltammetry and differential pulse voltammetry demonstrate excellent selectively and sensitivity for AA, DA and UA, with typical peaks at ?0.08 V, +0.19 V, and +0.34 V (vs. SCE), respectively. Under optimum conditions, the calibration plots are linear in the 1–80 μM range for DA, in the 1–60 μM range for UA, and in the 0.5–60 μM range for UA, with detection limits of 0.47 μM, 0.28 μM and 0.59 μM, respectively. The sensor was successfully applied to the simultaneous determination of DA and UA in the presence of AA in spiked urine sample. 相似文献
799.
Masoud Vakili Maryam Karami Shahram Delfani Soheila Khosrojerdi Koosha Kalhor 《Journal of Thermal Analysis and Calorimetry》2017,129(2):629-637
The purpose of this study is to predict the thermal conductivity of copper oxide (CuO) nanofluid by using feed forward backpropagation artificial neural network (FFBP-ANN). Thermal conductivity of CuO nanofluid is measured experimentally using transient hot-wire technique in temperature range of 20–60 °C and in volume fractions of 0.00125, 0.0025, 0.005 and 0.01% for neural network training and modeling. In addition, in order to evaluate accuracy of modeling in predicting the coefficient of nanofluid thermal conductivity, indices of root-mean-square error, coefficient of determination (R 2) and mean absolute percentage error have been used. FFBP-ANN with two input parameters (volume fraction and nanofluid temperature) and one output parameter (nanofluid thermal conductivity) in addition to two hidden layers and one outer layer which purelin, logsig and tansig functions are used was considered as the most optimum structure for modeling with neuron number of 4–10–1. In this study, among common methods of theoretical modeling of nanofluid thermal conductivity, theoretical method of Maxwell and also multivariate linear regression model was used for explaining the importance of modeling and predicting the results using neural network. According to this research, the results of indices and predictions show high accuracy and certainty of ANN modeling in comparison with empirical results and theoretical models. 相似文献
800.
Azizolla Beheshti Kimia Nozarian Carmel T. Abrahams Hossein Motamedi 《Journal of Coordination Chemistry》2017,70(19):3394-3408
A 3-D cadmium-based coordination polymer, [CdCl2L]n (1) (where L = 1,1-(1,6-hexanediyl)bis(1,3-dihydro-3-methyl-1H-imidazole-2-thione), was synthesized and structurally characterized. The capability of the polymer as an efficient sorbent for Congo red (CR) removal from aqueous solution has been evaluated. Compound 1 has a tetrahedral arrangement with a CdS2Cl2 core. L in 1 is bidentate to two neighboring CdII centers via the methimidazole sulfurs to create 1D chains propagating along the c-axis. The remaining coordination sites are occupied by two terminal chlorides. The chains are further stabilized by intermolecular C–H?Cl hydrogen bonds between the chlorides and hydrogens of the imidazole rings. Parallel chains stack in the 3-D structure. The CdII polymer sorbent was characterized by infrared spectroscopy, elemental analysis, UV–vis, solid fluorescence and X-ray single-crystal diffraction. Sorption kinetics were studied by three kinetic models, second order, Elovich and intraparticle diffusion. The results indicate that the mechanism of the sorption process followed Elovich kinetic model. Sorption equilibrium was also studied with Langmuir, Temkin, and Freundlich isotherm models. The sorption process followed the Temkin isotherm. MIC, MBC, and DNA cleavage activities of 1 were also studied. Furthermore, the UV–vis and solid state fluorescence spectra of 1 were measured. 相似文献