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221.
222.
We investigate the morphologies and maximum packing density of thin wires packed into spherical cavities. Using simulations and experiments, we find that ordered as well as disordered structures emerge, depending on the amount of internal torsion. We find that the highest packing densities are achieved in low torsion packings for large systems, but in high torsion packings for small systems. An analysis of both situations is given in terms of energetics and comparison is made to analytical models of DNA packing in viral capsids. 相似文献
223.
Habibi Khorassani SM Ebrahimi A Maghsoodlou MT Shahraki M Price D 《The Analyst》2011,136(8):1713-1721
In the present work, for the first time, investigation of the initial fast step of reaction between 1,1,1-trichloro-3-methyl-3-phospholene (TCMP) and methanol was studied under a dry inert atmosphere by a newly constructed CSF apparatus by means of a further development in the configuration of the previous stopped-flow spectrophotometer (SFS). Hence, it was necessary to make many changes to the stopped-flow apparatus: replacement of the spectrophotometer amplifier with a conductance amplifier and the use of a conductivity cell to replace the optical one. The conductivity cell was made of polyethylene capillary tube (1 mm internal diameter; i.d.) and its inside dimensions were 1 mm i.d. × 3 mm long. Two tube electrodes which are made of stainless steel (0.8 mm i.d. × 14 mm long) were fixed at opposite ends of the observation cell and their outer surfaces were connected to the conductivity bridge amplifier by the two lead wires. The mixer was a 3-way Teflon valve and the distance between the mixer and the end of the observation cell was 30 mm. For each run, at least 24 μL of solution was required for a typical trace with a dead time of about 5 ms. Because of the extreme sensitivity of TCMP to moisture, the stopped-flow (CSF) apparatus was used inside a glove bag under a dry nitrogen atmosphere. Kinetic parameters for pseudo first-order reaction involving k(obs) = 30 s(-1) at 22 °C and activation energy E(a) = 13.55 KJ mol(-1) were successfully calculated for the initial fast step of the reaction between TCMP and methanol at 22 °C. 相似文献
224.
Synthesis of 1‐(Cyclohexylamino)‐2‐(aryl)pyrrolo[1,2‐a]quinoline‐3‐carbonitrile Derivatives Using a Mild,Four‐Component Reaction
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Malek Taher Maghsoodlou Nourallah Hazeri Khatereh Khandan‐Barani Sayyed Mostafa Habibi‐Khorasani Alireza Abedi 《Journal of heterocyclic chemistry》2014,51(Z1):E152-E155
1‐(Cyclohexylamino)‐2‐(aryl)pyrrolo[1,2‐a]quinoline‐3‐carbonitrile derivatives were synthesized in an efficient method from four‐component condensation reaction between cyclohexyl isocyanide, quinoline, malononitrile, and aromatic aldehydes in the presence of a catalytic amount of titanium dioxide (TiO2) in CH2Cl2 at ambient temperature in good yields. Silica gel column chromatography was employed for HCN elimination and then 1, 3 hydrogen shift was led to form final products 5a , 5b , 5c , 5d , 5e . 相似文献
225.
Mohammad Hossein Habibi Shahram Tangestaninejad A. Fallah-Shojaie I. Mohammadpoor-Baltork S. F. Tayyari 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):1863-1871
Several preparative routes to bis[N(substituted-phenyl) 4-nitro-thiobenzamidato] mercury(II) complexes are presented, including the reaction of mercury(II) oxide, fluoride, chloride, bromide, cyanide, acetate, and nitrate with N(substituted-phenyl) 4-nitro-thiobenzamide derivatives. 1 H-NMR, Raman, and IR measurements confirmed the complexation of mercury to sulphur. 相似文献
226.
Quantum mechanical study of tautomerism of methimazole and the stability of methimazole–I2 complexes
DFT and ab initio theoretical methods were used to calculate the relative stability of tautomers in the methimazole (MMI). The calculations show that the thione form of MMI 1 is more stable than the thiol tautomer in good agreement with the experimental results. The DFT and ab initio calculations were also used to determine the stability of MMI–I2 complexes. All methods suggest that the methimazole in the MMI–I2 complex exists almost exclusively as the thione tautomer. The Gibbs free energy difference between planar and perpendicular forms of thione tautomer of MMI–I2 complex indicates that the planar form is the predominant complex. The counterpoise corrected Gibbs free energy also shows that the MMI–I2(plan.) complex is more stable than the MMI–I2(perp.) complex. These predictions are in good agreement with the experimental results. By using the natural bond orbital (NBO) approach, the effects of charge transfer interactions on the stability of MMI–I2 complexes were investigated. The LP3(S)→σ*(I–I) and LP3(I)→σ*(N–H) charge transfer interactions may be very important in the stability of the planar form. The results show that the LP3(S)→σ*(I–I) charge transfer interaction causes a greater increase in the σ*(I–I) antibond occupation number, and concomitantly, a greater increase in the corresponding I–I bond length in the planar complex with respect to the perpendicular complex. The LP3(S)→σ*(I–I) charge transfer interaction is assisted by NHI intermolecular hydrogen bonding. The atom in molecule (AIM) analysis shows that the charge density and its Laplacian at the SI bond critical point of the planar complex is greater than the perpendicular complex. 相似文献
227.
228.
Mohammad Hossein Habibi Shahram Tangestaninejad Abdollah Fallah‐Shojaie Iraj Mohammadpoor‐Baltork Reza Mokhtari Neil R. Brooks William Clegg 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(11):m494-m495
The molecule of the title compound, [Hg(C13H9N2O2S)2], has approximate twofold rotation symmetry, with the Hg atom in an essentially linear two‐coordinate HgS2 environment supported by secondary π interactions with the nitrophenyl rings of both ligands. The ligands are in the imine–thiolate rather than the amine–thione tautomeric form. 相似文献
229.
The thioacetalisation of a variety of heterocyclic, aromatic, and aliphatic carbonyl compounds (1 mmol) with ethane-1,2-dithiol (1 mmol) using silica sulphuric acid (SSA) is presented as an efficient heterogeneous catalyst under mild and solvent-free conditions at 60°C. The thioacetals were formed within a short reaction time (1–34 min) and isolated with 90–98 % yield following an extractive procedure and chromatography on silica gel. The competitive protection reaction between aldehyde and ketone with ethane-1,2-dithiol afforded the protected derivatives of benzaldehyde and acetophenone with 92 % and 8 % yields, respectively, indicating some selectivity. 相似文献
230.
Ghasem Marandi Nourallah Hazeri Malek T. Maghsoodlou Sayyed M. Habibi‐Khorassani Niloufar Akbarzadeh Torbati Faramarz Rostami‐Charati Brian W. Skelton Mohamed Makha 《Journal of heterocyclic chemistry》2013,50(3):568-572
1,10‐Phenanthroline reacts with malonitrile and aldehydes in the presence of isocyanides as domino‐Knoevenagel‐nucleophilic cycloaddition for generation of a new class of 10‐(aryl)‐11‐(alkyl‐ or arylamino‐)pyrrolo[1,2‐a][1,10]phenanthroline‐9‐carbonitrile compounds in excellent yield. All compounds are fully characterized with one structurally authenticated by a single X‐ray diffraction study. 相似文献