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111.
Jong-Seong Kim 《Tetrahedron letters》2005,46(2):277-279
The synthesis of new difunctional (i.e., light-emitting and hole-transporting) fluorophore molecules, 2,2′-difuryl-4,4′-(N,N,N′,N′-tetraphenyl)diaminobiphenyl and 5,5′-bis(4-N,N′-diphenylaminophenyl)-2,2′-bifuryl, which contain hole-transporting triphenylamino units, are reported. These difunctional molecules emit intense blue photoluminescence and further reveal high HOMO energy values as well as high glass transition temperatures. 相似文献
112.
Juan Du Zhen Chen Yu‐Long Wu Ming‐De Yang Jie Dang Jian‐Jun Yuan 《Crystal Research and Technology》2014,49(12):959-964
Four methods including hydrothermal method, glycol‐hydrothermal method, microwave‐hydrothermal method and glycol‐microwave‐hydrothermal method were used to prepare magnesium oxide precursor by the reaction of MgSO4·7H2O with (NH4)2CO3. The composition, crystallinity, morphology, aspect ratio, yield, functional groups, atom distribution, and interplanar spacing of the sample were investigated by X‐ray diffraction (XRD), Scan Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FT‐IR), and High Resolution Transmission Electron Microscope (HRTEM). The properties of Magnesium Oxide precursor were compared with each other. The results of FT‐IR and XRD showed that the crystals were all nesquehonite. However, it was shown by FT‐IR results that the crystals prepared by glycol‐microwave‐hydrothermal method contained OH− and HCO3− groups, which indicated that the Mg(OH)(HCO3)·2H2O type crystals would be facilitated by this method. The glycol‐hydrothermal method can create high quality Magnesium Oxide precursor with a high degree of crystallinity, high purity, high aspect ratio, smooth surface, and good dispersibility. 相似文献
113.
《代数通讯》2013,41(8):3227-3245
Abstract We determine the number of elements of order two in the group of normalized units V(𝔽2 G) of the group algebra 𝔽2 G of a 2-group of maximal class over the field 𝔽2 of two elements. As a consequence for the 2-groups G and H of maximal class we have that V(𝔽2 G) and V(𝔽2 H) are isomorphic if and only if G and H are isomorphic. 相似文献
114.
J.L. Fry 《Annals of Physics》2010,325(12):2668-2678
Quantum and classical mechanics are two conceptually and mathematically different theories of physics, and yet they do use the same concept of classical mass that was originally introduced by Newton in his formulation of the laws of dynamics. In this paper, physical consequences of using the classical mass by both theories are explored, and a novel approach that allows formulating fundamental (Galilean invariant) theories of waves and particles without formally introducing the classical mass is presented. In this new formulation, the theories depend only on one common parameter called ‘wave mass’, which is deduced from experiments for selected elementary particles and for the classical mass of one kilogram. It is shown that quantum theory with the wave mass is independent of the Planck constant and that higher accuracy of performing calculations can be attained by such theory. Natural units in connection with the presented approach are also discussed and justification beyond dimensional analysis is given for the particular choice of such units. 相似文献
115.
116.
在DEA数据标准化、基于弱有效和算术平均的方向距离函数模型效率测量方法的基础上,定义了一组基于强有效和广义平均的具备单位不变性的方向距函数效率测量方法,并进一步定义了基于强有效和广义平均的效率测量方法,克服了效率测量投入指标和产出指标作用不平衡的问题. 相似文献
117.
在单目标、单约束条件下,建立了三状态并-串联系统的优化模型,采用选取重要部件的方法优化系统可靠度,并相应地给出优化算法,最后通过例子,验证了该算法的有效性. 相似文献
118.
现代图形处理器(graphics processing units,GPU)具有较强的并行数值运算功能.该文简单介绍了GPU的硬件结构,基于GPU通用计算的数据结构和实现方法,以及用于编写片元程序的OpenGL着色语言.介绍了应用GPU计算大规模力学问题的研究进展.简要介绍了以下内容:应用GPU模拟自然界的流体现象,其实质是使用有限差分法求解Navier-Stokes方程;应用GPU实现有限元法计算,使用基于GPU的共轭梯度法求解有限元方程组;应用GPU实现分子动力学计算,用GPU计算原子间短程作用力,并生成邻近原子列表;应用GPU实现量子力学Monte Carlo计算;应用GPU实现n个物体的引力相互作用,用GPU纹理存储n个物体的位置、质量、速度和加速度等.对基于图象处理器和中央处理器的计算作比较,已完成了以下基于GPU的计算:实现求解线性方程组的高斯消元法和共轭梯度法,并应用于大规模的有限元计算;加速无网格法计算;加速线性和非线性分子结构力学方法计算;用于计算分析碳纳米管的力学性能.指出GPU在大规模力学计算中的研究方向. 相似文献
119.
A new sodium hydroxygallophosphate containing tetrameric gallium units: Na3[Ga4O(OH)(H2O)(PO4)4]·H2O
A new sodium hydroxygallophosphate, Na3Ga4O(OH)(H2O)(PO4)4·H2O, has been prepared by hydrothermal synthesis. Its structure has been determined from a single-crystal X-ray diffraction study. It crystallizes in the P21/c space group with the cell parameters a=9.445(2) Å, b=9.028(1) Å, c=19.209(3) Å, β=102.08(2), V=1603.4(4) Å3. Its three-dimensional framework can be described from PO4 monophosphate groups sharing their apices with original Ga4O16(OH)(H2O) tetrameric building units, which result from the assembly of one GaO4 tetrahedron, one GaO5 trigonal bipyramid and two octahedra: GaO5(OH) and GaO4(OH)(H2O). The sodium cations and one water molecule are located in tunnels running along b. 相似文献
120.
M. T. Oms R. Forteza V. Cerdà F. García A. L. Ramos 《International journal of environmental analytical chemistry》2013,93(1-4):1-14
Abstract The use of variable-angle fluorescence spectra together with multilinear curve-fitting techniques for the resolution of mixtures of polycyclic aromatic hydrocarbons (PAHs), is described. Only one spectrum is necessary to determine four compounds in a mixture even when a severe overlap occurs. The PAHs are quantified at ng/ml levels. 相似文献