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311.
Saeed Dehghanpour Richard Welter Aliou Hamady Barry Farzaneh Tabasi 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(4):1236-1243
Synthetic methods for several novel phosphoramidate compounds containing the P(O)NHC(O) bifunctional group were developed. These compounds with the general formula R1C(O)NHP(O)(N(R2)(CH2C6H5))2, where R1 = CCl2H, p-ClC6H4, p-BrC6H4, o-FC6H4 and R2 = hydrogen, methyl, benzyl, were characterized by several spectroscopic methods and analytical techniques. The effects of phosphorus substituents on the rotation rate around the P–Namine bond were also investigated. 1H NMR study of the synthesized compounds demonstrated that the presence of bulky groups attached to the phosphorus center and electron withdrawing groups in the amide moiety lead to large chemical-shift non-equivalence (ΔδH) of diastereotopic methylene protons. The crystal structures of CCl2HC(O)NHP(O)(NCH3(CH2C6H5))2, p-ClC6H4C(O)NHP(O)(NCH3(CH2C6H5))2, CCl2HC(O)NHP(O)(N(CH2C6H5)2)2 and p-BrC6H4C(O)NHP(O)(N(CH2C6H5)2)2 were determined by X-ray crystallography using single crystals. The coordination around the phosphorus center in these compounds is best described as distorted tetrahedral and the P(O) and C(O) groups are anti with respect to each other. In the compound Br-C6H4C(O)NHP(O)(N(CH2C6H5)2)2 (with two independent molecules in the unit cell), two conformers are connected to each other via two different N–H?O hydrogen bonds forming a non-centrosymmetric dimer. In the crystalline lattice of other compounds, the molecules form centrosymmetric dimers via pairs of same N–H?O hydrogen bonds. The structure of CCl2HC(O)NHP(O)(N(CH2C6H5)2)2 reveals an unusual intramolecular interaction between the oxygen of CO group and amine nitrogen. 相似文献
312.
Raissi H Moshfeghi E Farzad F 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,62(4-5):1004-1015
The molecular structure, intramolecular hydrogen and vibrational frequencies of 4-methylamino-3-penten-2-one were investigated by a series of density functional theoretical (DFT) calculations and ab initio calculation at the post-Hartree-Fock (MP2) level. Fourier transform infrared and Fourier transform Raman spectra of this compound and its deuterated analogue were clearly assigned. The calculated geometrical parameters show a strong intramolecular hydrogen bond with a N...O distance of 2.622-2.670 A. This bond length is about 0.02 A shorter than that in its parent, 4-amino-3- penten-2-one which is in agreement with spectroscopic results. Furthermore, the conformations of methyl groups with respect to the plane of the molecule and with respect to each other were investigated. 相似文献
313.
Different phenomenological equations based on plasticity, primary creep (as a viscoplastic mechanism), secondary creep (as another viscoplastic mechanism) and different combinations of these equations are presented and used to describe the material inelastic deformation in uniaxial test. Agreement of the models with experimental results and with the theoretical concepts and physical realities is the criterion of choosing the most appropriate formulation for uniaxial test. A model is thus proposed in which plastic deformation, primary creep and secondary creep contribute to the inelastic deformation. However, it is believed that the hardening parameter is composed of plastic and primary creep parts. Accordingly, the axial plastic strain in a uniaxial test may no longer be considered as the hardening parameter. Therefore, a proportionality concept is proposed to calculate the plastic contribution of deformation. 相似文献
314.
A. Tcharkhtchi S. Farzaneh B. Esmaeillou F. Nony A. Baron 《International Journal of Polymer Analysis and Characterization》2014,19(7):571-584
This study concerns the effect of thermal aging on mechanical properties of polyurethane. Polyurethane samples were exposed at 85° and 120°C under inert atmosphere. Mechanical tests were carried out on these samples the aging period. Tensile tests were performed to see the effect of aging on elastic modulus (E), stress (σr), and strain (?r) at break. It was shown that there are two distinct periods. Due to aging, E and σr increase in the first period, then they decrease in the second period. ?r decreases first and then increases. Fatigue tests were performed on unaged and aged samples. It was shown that the fatigue behavior of polyurethane (PU) is improved the same way during the first stage of aging. In the second step, the number of cycles to failure increases due to aging. The results show that aging has an important effect on mechanical properties of PU. The strain at break decreases during the first step of aging due to post-cross-linking and then increases due to chain scission in the network. Based on these results, the effect of cross-linking and chain scission on the mechanical properties of PU was discussed. 相似文献
315.
In this study, a simple, rapid and efficient method, dispersive liquid-liquid microextraction (DLLME) combined gas chromatography-electron capture detection (GC-ECD), for the determination of chlorobenzenes (CBs) in water samples, has been described. This method involves the use of an appropriate mixture of extraction solvent (9.5 μl chlorobenzene) and disperser solvent (0.50 ml acetone) for the formation of cloudy solution in 5.00 ml aqueous sample containing analytes. After extraction, phase separation was performed by centrifugation and the enriched analytes in sedimented phase were determined by gas chromatography-electron capture detection (GC-ECD). Our simple conditions were conducted at room temperature with no stiring and no salt addition in order to minimize sample preparation steps. Parameters such as the kind and volume of extraction solvent, the kind and volume of disperser solvent, extraction time and salt effect, were studied and optimized. The method exhibited enrichment factors and recoveries ranging from 711 to 813 and 71.1 to 81.3%, respectively, within very short extraction time. The linearity of the method ranged from 0.05 to 100 μg l−1 for dichlorobenzene isomers (DCB), 0.002-20 μg l−1 for trichlorobenzene (TCB) and tetrachlorobenzene (TeCB) isomers and from 0.001 to 4 μg l−1 for pentachlorobenzene (PeCB) and hexachlorobenzene (HCB). The limit of detection was in the low μg l−1 level, ranging between 0.0005 and 0.05 μg l−1. The relative standard deviations (R.S.D.s) for the concentration of DCB isomers, 5.00 μg l−1, TCB and TeCB isomers, 0.500 μg l−1, PeCB and HCB 0.100 μg l−1 in water by using the internal standard were in the range of 0.52-2.8% (n = 5) and without the internal standard were in the range of 4.6-6.0% (n = 5). The relative recoveries of spiked CBs at different levels of chlorobenzene isomers in tap, well and river water samples were 109-121%, 105-113% and 87-120%, respectively. It is concluded that this method can be successfully applied for the determination of CBs in tap, river and well water samples. 相似文献
316.
Mahsa Kiani Mojtaba Bagherzadeh Soraya Meghdadi Farzaneh Fadaei-Tirani Kurt Schenk-Joß Navid Rabiee 《应用有机金属化学》2020,34(4):e5531
The complexes PdII(qcq)(OAc) and PtII(qcq)Cl have been synthesized using environmentally benign synthesized ligands and characterized by elemental analyses: Fourier transform infrared spectroscopy, UV–visible spectroscopy, 1H NMR spectroscopy, and X-ray diffraction. The catalytic activity of the complex was assessed, in different media, for the Mizoroki–Heck coupling reaction for typical aryl halides and terminal olefins under aerobic conditions. Since the base and the solvent were found to influence the efficiency of the reaction, reaction conditions, temperature, time, and the amount of K3PO4 and a mixture of H2O/PEG, were optimized. We found, for the Mizoroki–Heck reaction coupling less reactive aryl chloride derivatives with olefins, promising activity for palladium catalysts. The electrochemical behavior of Hqcq and the Pd(II) complex was investigated by cyclic voltammetry and irreversible PdII/I reductions were observed. Hqcq and the Pd(II) and Pt(II) complexes were also screened for their in vitro antibacterial activity. They showed promising antibacterial activity comparable to that of the antibiotic penicillin. 相似文献
317.
Shadlaghani Arash Farzaneh Mahsa Shahabadi Mohammad Tavakoli Mohammad Reza Safaei Mohammad Reza Mazinani Iman 《Journal of Thermal Analysis and Calorimetry》2019,135(2):1429-1442
Journal of Thermal Analysis and Calorimetry - In this paper, the effect of internal serrated fins and eccentricity on natural convection heat transfer between annular spaces with the equivalent... 相似文献
318.
319.
Sara Sobhani Fatemeh Nasseri Farzaneh Zarifi 《Journal of the Iranian Chemical Society》2018,15(12):2721-2732
320.
Zahra Azarkamanzad Faezeh Farzaneh Mahboobeh Maghami Jim Simpson Mohammad Azarkish 《应用有机金属化学》2018,32(3)
The 2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine (tptz) undergoes hydrolysis in the presence of VO(SO4) in an alkaline solution, affording mainly the bis(2‐pyridyl carbonyl)amid ) VO2 complex, designated as [VO2(bpca)]. Single‐crystal X‐ray crystallography revealed that the coordination of V in complex is a distorted square‐pyramid coordinated with three nitrogen of bis(2‐pyridyl carbonyl)amid ) ligand and two binding oxygen atoms. The prepared complex which successfully supported on modified Fe3O4 nanoparticles using tetraethylorthosilicate (TEOS) and (3‐aminopropyl)trimethoxysilane(APTMS)was designated as Fe3O4@SiO2@APTMS@[VO2(bpca)] complex (nanocatalyst). The complex and nanocatalyst were characterized by means of FT‐IR, XRD, VSM, SEM and TEM. The catalytic activity of [VO2(bpca)] complex and Fe3O4@SiO2@APTMS@complex as catalysts 1 and 2 were evaluated by the epoxidation of geraniol , 3‐methyl‐2‐buten‐1‐ol , trans‐2‐hexen‐1‐ol and 1‐octen‐3‐ol with 70–98% conversions and 95–100% selectivities. Based on the obtained results, the heterogeneity and reusability of the catalyst seems promising. In addition, the in vitro antibacterial activity of [VO2 (bpca)] complex have also been evaluated and compared to the activities of other vanadium complexes, tptz ligand and two standard antibacterial drugs, Nalidixic acid and Vancomycin. 相似文献