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101.
《Physics letters. A》2014,378(30-31):2020-2023
102.
梯形箱梁剪力滞后效应的精细化分析 总被引:1,自引:1,他引:0
引入剪滞翘曲应力自平衡条件的影响,考虑了剪切变形和剪滞效应等因素,设置了三个不同的剪滞纵向位移差函数以准确反映梯形箱梁不同宽度翼板的剪滞变化幅度,提出了一种能对工程中常用箱梁静力学特性分析的精确解法。本文以能量变分原理为基础建立了薄壁箱梁的弹性控制微分方程和自然边界条件,获得了相应广义位移的闭合解。算例中,分析了不同荷载形式、跨宽比和悬臂板长度等因素对箱梁静力学特性的影响,结果显示出引入剪滞翘曲应力自平衡条件的必要性。 相似文献
103.
We study the electron transport properties of graphene anti-dot and periodic graphene anti-dot arrays using the nonequilibrium Green?s function method and Landauer–Büttiker formula. Fano resonant peaks are observed in the vicinity of Fermi energy, because discrete states coexist with continuum energy states. These peaks move closer to Fermi energy with increasing the width of anti-dots, but move away from the Fermi energy with increasing the length of anti-dots. When N periodic anti-dots exist in the longitude direction, a rapid fluctuation appears in the conductance with varying resonance peaks, which is mainly from the local resonances created by quasibound state. When P periodic anti-dots exist in the transverse direction, P-fold resonant splitting peaks are observed around the Fermi energy, owing to the symmetric and antisymmetric superposition of quasibound states. 相似文献
104.
This paper is concerned with the existence, uniqueness and asymptotic behavior of solutions for the quasilinear parabolic systems with mixed quasimonotone reaction functions endowed with Dirichlet boundary condition, in which the elliptic operators are allowed to be degenerate. By the method of the coupled upper and lower solutions and its monotone iterations, it is shown that a pair of coupled upper and lower solutions ensures that the unique positive solution exists and is globally stable if the quasisolutions are equal. Moreover, we study the asymptotic behavior of solutions to the Lotka-Volterra predator-prey model with the density-dependent diffusion. 相似文献
105.
在Rayleigh散射Doppler激光雷达的风场反演过程中,除了温度、压强等因素之外,风速反演结果的 准确性还受到Mie散射信号的影响.当Mie散射信号较强时,尤其是遇到高层云或火山灰等情况,如果仍不考虑 气溶胶信号,由于温度不确定度和气溶胶信号的综合影响,风速反演结果将与真值偏差很大.本文提出了利用 激光雷达在垂直方向的测量信号同时反演后向散射比和大气温度的非线性迭代算法,并优化给出了最佳的 初始发射激光工作点.仿真试验结果表明:该方法可以准确有效地反演后向散射比;将该方法结合非线性迭代 风速反演方法,可以有效消除气溶胶后向散射信号的影响,进一步提高大气风速和温度的反演精度. 相似文献
106.
107.
OH− and Cl− doped Bi4Ge3O12 (BGO) single crystals had been grown by Vertical Bridgman (VB) method. The structure of these crystals was determined by XRD, the transmittance and emission spectra in near infrared region (NIR) were measured at room temperature. 5% OH− doped BGO shows a significant emission band peaking around 1181 nm under 808 nm laser diodes (LDs) excitation, and the 5% Cl− doped BGO exhibits a relatively weak emission band as well. 100% and 5% OH− doped BGO show noticeable emission band centered at about 1346 nm under 980 nm LDs excitation. 相似文献
108.
2.0 mol% (relative to Ba2+) Yb3+ doped α-BaB2O4 (α-BBO) crystal was obtained by the Czochralski method. The doped crystal structure was determined by means of an X-ray diffraction analysis. The absorption, near-infrared (NIR) luminescence spectra and fluorescence decay curve of Yb3+ doped α-BBO crystal were investigated. NIR emission under 940 nm and 980 nm LDs (laser diodes) excitation was observed in the Yb doped α-BBO crystal. 相似文献
109.
《Solid State Sciences》2012,14(4):445-450
A novel 3d-4f heterometallic coordination polymer, {[Tm5(μ3-OH)2(BDC)6(IN)2Cu(H2O)2]·(H2O)3}n (1) [BDC = benzene-1,2-dicarboxylate, IN = isonicotinate], has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction, FTIR, elemental analysis, powder X-ray diffraction and thermogravimetric analysis. The compound crystallizes in monoclinic system, space group P21/c (No. 14), a = 13.7302(5) Å, b = 23.5428(3) Å, c = 21.5789(2) Å, β = 91.491(3)°, V = 6973.0(3) Å3, and Z = 4. The structure exhibits unusual two-dimensional Tm-carboxylate layer, which is constructed from the expansion of novel pentanuclear {Tm5} clusters. More interestingly, the heterometallic Cu(I) ions were successfully planted into such Ln-carboxylate layer by the bifunctional IN bridging ligands, resulting in the formation of an unprecedented 2D heterometallic lanthanide-transition-metal framework. 相似文献
110.
The saturation molality of α-d-xylose(cr) in water was measured by using HPLC and is m(sat) = (8.43 ± 0.42) mol · kg−1 at T = 298.15 K. It was also established that the anhydrous form of α-d-xylose(cr) is the crystalline form that is in equilibrium with the aqueous solution at T = 298.15 K. Solution calorimetry was used to measure the following standard molar enthalpies of solution at T = 298.15 K: = (12.10 ± 0.12) kJ · mol−1 for α-d-xylose(cr); = −(8.1 ± 2.7) kJ · mol−1 for 1,4-β-d-xylobiose(am); and = −(24.1 ± 6.4) kJ · mol−1 for 1,4-β-d-xylotriose(am). It was observed that both 1,4-β-d-xylobiose(am) and 1,4-β-d-xylotriose(am) were amorphous substances and that they form thick gels in water in which no solid phase is present. Consequently, it is not possible to measure m(sat) for these two substances. All substances were carefully characterized by using both HPLC and Karl Fischer analysis. NMR was used to measure the anomeric purity of the α-d-xylose(cr). Thermodynamic network calculations were used to calculate standard molar formation properties for the aforementioned substances. 相似文献