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1.
We have calculated the spherical v0 and anisotropic radial components v2 and v4 in the usual Legendre expansion for the rigid rotor He-N2 potential using the method of Tang and Toennies Potential curves covering the range of internuclear distances from 2.5 to 8.0 Å, which includes the minimum region, arc presented and compared with a recent experimental potential derived from differential total cross sections. 相似文献
2.
用ICP-AES法测定了东太平洋深海锰结核样品中二十多种主,次及微量元素,结果表明,表面瘤状和表面光滑两种类型锰结核的化学元素含量有较明显的区别,如表面光滑的锰结核TiO2含较高,而表面瘤状的锰结核Mn/Fe之值较高等。 相似文献
3.
用原子吸收光谱法测下了“东北水三七”根、茎、叶的21种化学元素,结果表明,不同部位的元素含量有一定差别。 相似文献
4.
CLIMATIC CHANGE SINCE LITTLE ICE AGE RECORDED BY DUNDE ICE CAP 总被引:21,自引:0,他引:21
The climatic change since the Little Ice Age recorded in the Dunde Ice Cap is presentedin this paper. There have been three cold periods and three warm periods since 1400AD.Among them, the coldest one was in the 17th century. Many evidences verified the three coldand warm variations recorded in the Dundc Ice Cap. But it was found from the comparison between the Dunde Icc Cap climatic record and thewinter temperature record in Shanghai that there was a temporal dfference in climatic changebetween East China and West China. The general trend is that the cooling and warmingprocesses in West China were earlier than that in East China. In the Dunde Ice Cap, it isnow in an anomalous warm period, while it is not as warm as in Dunde Ice Cap recordaccording to the winter temperature in Shanghai. In addition to the possible cause of temporaldifference in climatic change between West China and East China, another possible cause isthat the greenhouse effect of CO_2 may already be recognizable in the Dunde Ice Cap a 相似文献
5.
The phases occurring in samples of gross composition BaxWO3 (0.01 < x < 0.33) heated at temperatures between 1073 and 1373°K have been determined using X-ray diffraction and electron microscopy. At all temperatures a tetragonal tungsten bronze phase with a narrow homogeneity range of x = 0.20?0.21 was observed to form. In addition, at temperatures up to 1273°K, a series of orthorhombic intergrowth bronzes forms within a restricted composition range around x = 0.04. The latter phases are unstable at higher temperatures and were not found in preparations made at 1323°K. Similarly a new type of bronze phase forms at x = 0.14?0.16 at temperatures up to 1323°K, but not at 1373°K. The structure of this phase is unknown. Aspects of the crystal chemistry of the barium bronzes and the relationships to other bronze phases are discussed. 相似文献
6.
AlSiP3 is formed by heating aluminum and silicon powder with red phosphorus and adding small amounts of iodine or AlCl3. Small, black crystals with metallic lustre grow at 1200°K. The compound crystallizes in the orthorhombic space group Pmnb (No. 62) with a = 987.2 pm, b = 586.1 pm, c = 608.8 pm and four formula units. In the structure isolated P atoms as well as P2 pairs are present (PP = 218.2 pm). Silicon is tetrahedrally bonded (SiP = 224.2 ? 228.2 pm) whereas aluminum has octahedral coordination (AlP = 244.2 – 260.8 pm). The structure can be described as an intergrowth structure of wurtzite and pyrite type. 相似文献
7.
R. Lefbvre 《Chemical physics letters》1980,70(3):430-433
The complex rotation method is applied to the determination of widths and shifts of an harmonic oscillator predissociated by a linear potential, for when exact analytical formulas are available in the limit of small interchannel coupling. Excellent agreement is obtained. 相似文献
8.
The 57Fe Mössbauer effect in [Fe(pythiaz)2] (BF4)2 (I) and [Fe(pythiaz)2] (C&O4)2 (II) has been studied between 298 and 4.2°K (pythiaz = 2,4-bis(2-pyridyl)thiazole). At 298°K compound I shows a doublet with ΔEQ(5T2) = 1.29 mm sec?1 and δ1S(5T2) = +0.93 mm sec?1 characteristic of a 5T2 ground state. At 236°K, a second doublet, typical for a 1A1 ground state appears. The transition 5T2 å 1A1 progresses as the temperature is lowered but levels off below ≈ 120°K. At 4.2°K, 59% of the intensity is due to the 1A1 state, and ΔEQ(1A1) = 1.59 mm sec?1 and δ1S(1A1) = +0.26 mm sec?1. In an applied magnetic field, Vzz(1A1) < 0 has been determined Similar results have been obtained with compound II.Debye-Waller factors f5T2 and f1A1. were determined from the Mössbauer spectra under the assumption of Curie-Weiss dependence of the magnetism for the 5T2 and constant μeff for the 1A1 ground state. The resulting temperature dependence of f1A1 is highly unusual thus suggesting complicated magnetic behaviour of both ground states in the transition region. Two mechanisms for the nature of the transition are discussed, a “spin-flip” mechanism being the physically more reasonable one. The assumption of a simple Boltzmann distribution (“spin equilibrium”) may be ruled out for the solid but could be encountered in solutions. 相似文献
9.
C.N.R. Rao D.D. Sarma P.R. Sarode E.V. Sampathkumaran L.C. Gupta R. Vijayaraghavan 《Chemical physics letters》1980,76(3):413-415
The valence state of Yb in some of its intermetallics, YbNi2Ge2, YbCu2Si2 and YbPd2Si2 has been investigated by LIII(Yb) absorption edges and X-ray pnotoelectron spectra in the 4f and 4d regions. These studies establish the presence of mixed valence in all three systems and illustrate the utility of 4f and 4d spectra in the study of mixed valence in Yb compounds. 相似文献
10.