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51.
The present study illustrated the stability of linkage isomers of [Fe(CO)4(NCS)]? and [Fe(CO)4(SCN)]? by the use of PBE quantum method. It also investigated the polarity of solvent effect on dipole moment, structural parameters, and frontier orbital energies of complexes. The results indicated that the polarity of solvent had a significant effect on the frontier orbital energies and HOMO-LUMO gap. The character of Fe-C bonds of molecules was analyzed by Natural bond orbital (NBO) analysis. Back-bonding effect in these bonds was explored with calculation of quadrupole polarization of carbon atom by QTAIM analysis. Also, 14N NQR parameters were used for the illustration of Fe-NCS and Fe-SCN bonds. 相似文献
52.
Mercuric fluoride (HgF2), as a light-sensitive inorganic compound, in the presence of dioxygen is able to convert various α-aryl- and α,α-diarylcarboxylic acids into the corresponding aldehydes and ketones selectively under photoirradiation via trapping of the benzylic radical by O2. 相似文献
53.
Motivated by the recent work of Elizalde et al. [E. Elizalde, S. Nojiri, S.D. Odintsov, D. Saez–Gomez, V. Faraoni, Phys. Rev. D 77 (2008) 106005], we generalize their work to the non-flat case. We consider a universe filled with matter and show that it is possible to obtain both inflation and accelerated expansion at late times by using a single scalar field. Realistic examples are worked out in order to illustrate this fact. Then we extend the problem to the interacting case. 相似文献
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56.
Mohammad Reza Saeb Yousef Mohammadi Amir Saeid Pakdel Alexander Penlidis 《Macromolecular theory and simulations》2016,25(4):369-382
A Kinetic Monte Carlo (KMC) simulation approach has been adopted in this study to capture evolutionary events in the course of free radical copolymerization, through which batch and starved‐feed semibatch processes are compared. The implementation of the KMC code developed in this work: (i) enables satisfactory control of the molecular weight of the copolymer by tracking the profiles of concentrations of macroradicals, monomers, and polymer as well as degree of polymerization, polydispersity, and chain length distribution; (ii) captures the bivariate distribution of chain length and copolymer composition; (iii) comprehensively tracks and analyzes detailed information on the molecular architecture of the growing chains, thus distinguishing between sequence length and polydispersity of chains produced in batch and starved‐feed semibatch operations; (iv) makes possible the screening of products, based on such details as the number and weight fractions of products having different comonomer units located at various positions along the copolymer chains. The aforementioned characteristics are achieved by stochastic calculations through code developed in‐house. This KMC simulator becomes a very useful tool for the development of tailored copolymers through free radical polymerization, with blocks separated with single units of a different type.
57.
NiO nanoparticles with an average size of 15 nm were easily prepared via the thermal decomposition of the tris(ethylenediamine)Ni(II) nitrate complex [Ni(en)3](NO3)2 as a new precursor at low temperature, and the nanoparticles were characterized by thermal analysis (TGA/DTA), X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FT-IR), UV-Vis spectroscopy, BET specific surface area measurement, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and magnetic measurements. The magnetic measurements confirm that the product shows a ferromagnetic behavior at room temperature, which may be ascribed to a size confinement effect. The NiO nanoparticles prepared by this method could be an appropriate photocatalytic material due to a strong absorption band at 325 nm. This method is simple, fast, safe, low-cost and also suitable for industrial production of high purity NiO nanoparticles for applied purposes. 相似文献
58.
NiO nanoparticles with an average size of 12 nm and a high specific surface area of 88.5 m2/g were easily prepared via the thermal decomposition of the complex Ni(dmgH)2 and were characterized by TGA, XRD, FT-IR, TEM and BET surface area measurement. This nanosized transition metal oxide was used as a new heterogeneous catalyst for the reduction of nitroarenes under microwave irradiation. The efficient and selective reduction of aromatic nitro compounds into their corresponding amines was observed by using ethanol as a hydrogen donor (reducing agent) and KOH as a promoter under microwave irradiation. This highly regio- and chemoselective method is fast, simple, inexpensive, high yielding, clean and compatible with several sensitive functionalities, such as halogens, -OH, -OCH3, -CHO, -COCH3, -COOH, -COOEt, -CONH2, -CN, -CHCH2 and -NHCOCH3. This method is suitable for the large scale preparation of different substituted anilines as well as other arylamines. In addition, the catalytic activity of nanosized NiO is higher than that of the bulk sample. 相似文献
59.
Abedi A Safari N Amani V Khavasi HR 《Dalton transactions (Cambridge, England : 2003)》2011,40(26):6877-6885
The complexes [Fe(dm4bt)(3)][FeCl(4)](2) (1) and [Fe(dm4bt)(3)][FeBr(4)](2) (2) were prepared from the reaction of 2,2'-dimethyl-4,4'-bithiazole (dm4bt) with FeCl(3)·6H(2)O and FeBr(3), respectively, in methanol. Both complexes were characterized by IR, UV-Vis and (1)H NMR spectroscopy and their structures were studied by single-crystal diffraction. The methylated bithiazole led to high spin Fe(II) centers in the octahedral cation part of complexes 1 and 2 with Fe-N distance of 2.220 ?, in spite of the low spin octahedral Fe(II) complexes with unsubstituted bithiazole ligands. Crystal structure determination of 2 was performed at 90, 120 and 298 K. Temperature reduction to 90 K resulted in a decrease in the Fe-N bond length to 2.206 ? which is still in the range of high spin Fe(II). Complex 1 shows a reversible mechanochromic effect from the crystalline phase to powder form from red to yellow; it also displays reversible photochromism from yellow to green in solution under sunlight. The magnetic behaviour of the complexes was also studied at 2-300 K. The temperature dependence of χ(m)T curves for the two forms of 1, crystal and powder, demands some changes in their magnetic behavior, causing different colors i.e. red and yellow. At low temperatures, χ(m)T decreases where the decrease starts at around 65 K for compound 1, and at around 100 K for compound 2, due to different counterions. The two complexes exhibit antiferromagnetism at around 4 K. 相似文献
60.
Abbas Afkhami Tayyebeh Madrakian Saeid Soltanbeygi Majid Rezaeivala 《Journal of Molecular Structure》2011,985(1):86-90
The complex formation between a new synthesized Schiff base and the cations Ni2+, Co2+, Cu2+, Zn2+ in dichloromethane (DCM) and chloroform solutions was investigated spectrophotometrically using rank annihilation factor analysis (RAFA). The results of mole ratio plots and continuous variation data show the stoichiometry of complexation were found to be 1:1, and 2:1 metal ion to ligand. The stoichiometry was obtained as 1:1 metal ion to ligand ratio for Co2+, Ni2+ and Zn2+ in chloroform and 2:1 for Cu2+. In DCM the stoichiometry was obtained as 1:1 for Co2+ and 2:1 for Ni2+ and Zn2+ and a consecutive 2:1 metal ion to ligand ratio was obtained for Cu2+. Formation constants of these complexes were estimated by application of RAFA on spectrophotometric data. In this process the contribution of ligand was removed from the absorbance data matrix when the complex stability constant acts as an optimizing object and simply combined with the pure spectrum of the ligand, the rank of the original data matrix can be reduced by one by annihilating the information of the ligand from the original data matrix. 相似文献