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61.
Some new bimetallic carboxylates of tin and germanium with general formula where R1 = m-CH3C6H4, p-CH3C6H4, C6H5, R2 = o-CH3C6H4, p-CH3C6H4, o-CH3OC6H4, C6H5, CH3, have been prepared by the condensation reaction of diethyltin oxide and triarygermyl(substituted)propanoic acid in 1:2 mole ratio, respectively, and characterized by multinuclear (1H, 13C, 119Sn) NMR, 119mSn Mössbauer and IR spectroscopy. The X-ray crystal structure of the ligand I4 [(C6H5)3GeCH(o-CH3OC6H4)CH2COOH] delineate four coordinated germanium atom with a peculiarity of having a molecule of solvent (CHCl3). The chiral center in the synthesized compounds was identified on the basis of 1H NMR data and measurements of angle of rotations. 相似文献
62.
Muhammad Kaleem Khosa Masood Parvez Muhammad Mazhar Saqib Ali Sadiq‐ur‐Rehman 《应用有机金属化学》2005,19(1):202-202
The germanium atom in [(C6H5)3GeCH(4‐ClC6H4)CH2C(C6H5)2OH] is in a distorted tetrahedral geometry. Steric hindrance precludes O? H···O intra‐ or inter‐molecular bonding. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
63.
Nadia Parveen Rabia Nazir Muhammad Mazhar 《Journal of Thermal Analysis and Calorimetry》2013,111(1):93-99
Tris(bipyridine)nickel(II) chloride (1) and bis(bipyridine)nickel(II) chloride (2) pyrolize at heating rate of 50 °C/min to a maximum of 450 °C for 24 h under an inert atmosphere of flowing argon gas, to yield size-controlled nickel nanoparticles. Thermogravimetric studies of the complexes (1) and (2) and GC–MS analysis of the trapped volatile matter evolved during thermal degradation of the complexes indicate their clean decomposition pathway to zero-valent nickel. Both heating rate and argon gas flow rate affect purity, particle size, and shape of the particles. X-ray powder diffractometry and atomic force microscopy showed the formation of face-centered cubic (fcc) structured nickel particles having particle size in the range of 3.5–5.0 nm. Magnetic susceptibility measurements suggest nickel nanoparticles to be ferromagnetic in nature characterized by particle size–dependent Curie temperature and high coercivity that is comparable to the bulk iron. 相似文献
64.
A series of Mn1−xCuxFe2O4, with x=0, 0.25, 0.50, 0.75 and 1.0, spinel ferrites were prepared by standard ceramic method, to study the effect of compositional variation on magnetic susceptibility, saturation magnetization (Ms), Curie temperature (Tc) and magnetic moments (μB). The Curie temperatures have been evaluated by measuring the ac susceptibility using the mutual inductance technique. On increasing Cu contents from 0.0 to 0.50, the saturation magnetization increases while the Curie temperature decreases. On further increase in Cu contents, x>0.50 a decreasing trend in Ms is exhibited while Tc continues to decrease. This effect can be partially related to the low magnetic moments of Cu+2 ions. The dominant interaction in all ferrite samples is A-B interaction which is due to the negative values of the characteristic temperature θ(K) showing that the magnetic ordering is antiferromagnetic. The Y-K angle increases gradually with increasing copper contents and extrapolates to 90° for CuFe2O4. From the computation of Y-K angles for Mn1−xCuxFe2O4, it can be concluded that the mixed copper ferrites exhibit a non-collinearity of the Y-K type while MnFe2O4 shows a Neel type of ordering. 相似文献
65.
Shabana Taj Din Muhammad M. Ashraf Chaudhry Muhammad Mazhar 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(1):79-88
Potassium iron(III) hexacyanoferrate(II) supported on poly methyl methacrylate, has been developed and investigated for the
removal of lithium, rubidium and cesium ions. The material is capable of sorbing maximum quantities of these ions from 5.0,
2.5 and 4.5 M HNO3 solutions respectively. Sorption studies, conducted individually for each metal ion, under optimized conditions, demonstrated
that it was predominantly physisorption in the case of lithium ion while shifting to chemisorption with increasing ionic size.
Distribution coefficient (K
d) values followed the order Cs+ > Rb+ > Li+ at low concentrations of metal ions. Following these findings Cs+ can preferably be removed from 1.5 to 5 M HNO3 nuclear waste solutions. 相似文献
66.
In this article, Laplace decomposition method (LDM) is applied to obtain series solutions of classical Blasius equation. The
technique is based on the application of Laplace transform to nonlinear Blasius flow equation. The nonlinear term can easily
be handled with the help of Adomian polynomials. The results of the present technique have closed agreement with series solutions
obtained with the help of Adomian decomposition method (ADM), variational iterative method (VIM) and homotopy perturbation
method (HPM). 相似文献
67.
Javed Ahmad Muhammad Qadeer AwanMuhammad Ehsan Mazhar Muhammad Naeem Ashiq 《Physica B: Condensed Matter》2011,406(2):254-258
Cobalt substituted nanosized magnesium aluminates having a nominal composition MgAl2−xCoxO4 where x = 0.0, 0.5, 1.0, 1.5, 2.0 were synthesized by the chemical co-precipitation method. Aluminium (Al3+) ions were completely and successfully substituted by Co2+ ions, which yielded an electron rich terminal compound MgCo2O4. All the samples were characterized by means of X-ray diffraction (XRD), thermogravimetry and differential thermal analysis (TG/DTA) and dc electrical resistivity measurements. The investigated samples were found to be spinel single phase cubic close packed crystalline materials as demonstrated by XRD data. Using the Debye Scherer formula, the calculated crystallite size was found Co2+ concentration dependent and varied between 7 and 19 nm. The lattice constant, X-ray density and bulk density were found to increase while percentage porosity decreases on increasing the Co2+ concentration. The dc electrical resistivity was found to decrease as a function of temperature as expected for a typical semiconductor. The doped Co2+ ions are believed to form small polarons and hopping of these small polarons between the adjacent sites seems to be partially responsible for conduction in the system. The activation energy of hopping of small polarons was also calculated. 相似文献
68.
Hassan Abrar Ul Sumrra Sajjad Hussain Zafar Muhammad Nadeem Nazar Muhammad Faizan Mughal Ehsan Ullah Zafar Muhammad Naveed Iqbal Mazhar 《Molecular diversity》2022,26(1):51-72
Molecular Diversity - During the present investigation, two new sulfonamide-based Schiff base ligands, 4-{[(2-hydroxy-3-methoxyphenyl)methylidene]amino}-N-(1,3-thiazol-2-yl)benzene-1-sulfonamide... 相似文献
69.
Comparative evaluation of magnetization transfer MR imaging and in-vivo proton MR spectroscopy in brain tuberculomas 总被引:3,自引:0,他引:3
Gupta RK Husain M Vatsal DK Kumar R Chawla S Husain N 《Magnetic resonance imaging》2002,20(5):375-381
We have compared and analyzed the value of in vivo proton MR spectroscopy (PMRS) and T1 weighted magnetization transfer (MT) MR imaging in tissue characterization of brain tuberculomas. We studied 33 cases of proven intracranial tuberculomas with in vivo PMRS and T1 weighted MT MR imaging. MT ratios from the rim and core of the tuberculomas were calculated and compared with metabolites seen on PMRS. Final diagnosis of tuberculoma was based on histopathology (n = 26) and/or associated tuberculous meningitis (n = 7) in all the cases. Out of the 33 patients who underwent both PMRS and T1 weighted MT MR imaging, spectroscopy showed only lipids at 0.9 ppm, 1.3 ppm, 2.0 ppm, and 2.80 ppm in 26 cases while lipids at 0.9 ppm, 1.3 ppm, 2.0 ppm and 2.80 ppm along with choline at 3.22 ppm was seen in remaining 7 patients. MT ratios from the core or solid necrosis varied from 21-29% while from the rim or cellular region varied from 16-24%. MT ratios from all the 33 lesions were consistent with tuberculomas while PMRS showed choline along with lipids in 7 predominantly cellular lesions simulating a neoplasm. We conclude that T1 weighted MT MR imaging appears to be more consistent in the tissue characterization of brain tuberculomas. 相似文献
70.
A numerical solution of the convective heat transfer in the thermal entry region of the finned double‐pipe is carried out for the case of hydro‐dynamically fully developed flow when subjected to uniform wall temperature boundary condition. Adaptive axial grid size is used in order to cater for the variation of large solution gradients in the axial direction. It has been observed that the thermal entrance region is highly effective and there is a substantial enhancement in the heat transfer coefficient. A maximum of 76.4877% increase has been observed in the thermal entrance region as compared with the fully developed region for 24 fins and H*=0.6 when R?=0.25, whereas for R?=0.5 the maximum increase is 75.0308% for the same number of fins of same height. It has been observed that no geometry consistently perform better throughout the entrance region. However, the geometries that have optimal performance in the fully developed region perform better in the developing region on average terms. Results show that the Nusselt number and the thermal entrance length are dependent upon various geometrical parameters such as ratio of radii of the inner and the outer pipe, fin height and the number of fins. The limiting case results match well with the literature results. This validates our numerical procedure and computer code. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献