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991.
Based on the Hirota bilinear form, a simple approach without employing the standard perturbation technique, is presented for constructing a novel N-soliton solution for a (3+1)-dimensional nonlinear evolution equation. Moreover, the novel N-soliton solution is shown to have resonant behavior with the aid of Mathematica. 相似文献
992.
采用高温固相法合成了NaBaPOM4:Tb3+绿色荧光粉, 并研究了材料的发光性质. NaBaPOM4:Tb3+材料呈多峰发射, 发射峰位于437、490、543、587和624 nm, 分别对应Tb3+的5D3→7F4和5D4→7FJ=6, 5, 4, 3跃迁发射, 主峰为543 nm; 监测543 nm发射峰, 所得激发光谱由4f75d1宽带吸收(200-330 nm)和4f-4f 电子吸收(330-400 nm)组成, 主峰为380 nm. 研究了Tb3+掺杂浓度, 电荷补偿剂Li+、Na+、K+和Cl-, 及敏化剂Ce3+对NaBaPOM4:Tb3+材料发射强度的影响. 结果显示: 调节激活剂浓度、添加电荷补偿剂或敏化剂均可以在很大程度上提高材料的发射强度. 相似文献
993.
用鲱鱼精DNA (hsDNA)修饰10 nm的纳米金制备了Hg2+的hsDNA修饰纳米金共振散射光谱探针(AuhsDNA). 在pH 7.0 Tris-HCl缓冲溶液中及0.017 mol/L NaCl存在下, Hg2+与AuhsDNA形成稳定的Hg2+-DNA结合物, 引起AuhsDNA中的纳米金析出并聚集形成纳米金簇. 该溶液用150 nm滤膜过滤后, 滤液中过量的AuhsDNA可催化Fehling试剂-葡萄糖反应生成氧化亚铜微粒, 该微粒在580 nm处有一个较强的共振散射峰. 随着汞离子浓度增大, 形成的纳米金簇越多, 滤液中AuhsDNA越少, 生成的氧化亚铜微粒减少, 580 nm处氧化亚铜微粒的共振散射光强度线性降低, 其共振散射光强度降低值?I580 nm与汞离子浓度在1~833 nmol/L范围内成线性, 回归方程、相关系数、检出限分别为
?I580 nm+0.9, 0.9990, 0.3 nmol/L Hg2+. 该法用于废水中Hg2+的检测. 相似文献
994.
In this paper a three-dimensional steady state model has been developed to study heat flow in dermal regions of tapered shape human limbs, which are elliptical in shape. The model incorporates the important biophysical parameters like blood mass flow rate, thermal conductivity and rate of metabolic heat generation. Appropriate boundary conditions have been framed using biophysical conditions. The finite element method has been employed using coaxial elliptical hexahedral elements to solve the problem. MATLAB 7.0 has been used to simulate the model and obtain numerical results. 相似文献
995.
Sumit Vyas 《Chinese Journal of Physics (Taipei)》2018,56(1):117-124
There has been a significant global interest in the thin film transistor (TFT) due to its potential use in flat panel display. A great deal of interest in zinc oxide (ZnO) based TFT has been developed owing to its promising electronic and optoelectronic properties. The performance of a TFT is mainly measured by calculating the turn-on voltage, drain current on-to-off ratio (Ion/Ioff) and channel mobility that depends on many factors like crystallanity of the active layer, quality of the insulator, and the quality of the interface between the different layers (semiconductor, insulator, and metallic contacts). All these factors further depend upon the growth and processing condition of different layers. This paper presents a short review that includes the factors affecting the performance of ZnO-based TFT and the methods to optimize them. The related work of reputed research groups are summarized and discussed systematically in the paper. 相似文献
996.
A dielectric constant of 27 was demonstrated in the as deposited state of a 5 nm thick, seven layer nanolaminate stack comprising Al2O3, HfO2 and HfTiO. It reduces to an effective dielectric constant (keff) of ∼14 due to a ∼0.8 nm interfacial layer. This results in a quantum mechanical effective oxide thickness (EOT) of ∼1.15 nm. After annealing at 950 °C in an oxygen atmosphere keff reduces to ∼10 and EOT increases to 1.91 nm. A small leakage current density of about 8 × 10−7 and 1 × 10−4 A/cm2, respectively at electric field 2 and 5 MV/cm and a breakdown electric field of about 11.5 MV/cm was achieved after annealing at 950 °C. 相似文献
997.
998.
Pb(Zr0.53Ti0.47)O3 (PZT) thin films with different thicknesses (99-420 nm) were prepared on Pt(1 1 1)/Ti/SiO2/Si(1 0 0) substrates by sol-gel method and films were annealed at 450 °C for 30 min using a single-mode cavity of 2.45 GHz microwaves. X-ray diffraction analysis indicated that the pyrochlore phase was transformed to the perovskite phase at above 166 nm films. The grain sizes were increased, surface roughnesses were decreased, and electrical properties were improved with film thickness. The leakage current density was 9 × 10−8 A/cm2 at an applied electrical field of 100 kV/cm. The ohmic and field-enhanced Schottky emission mechanisms were used to explain leakage current behavior of the PZT thin films. These results suggest that microwave annealing is effective for obtaining low temperature crystallization of thin films with better properties. 相似文献
999.
In this paper, by using the symmetry method, the relationships between new explicit solutions and old ones of the (2+1)-dimensional Kaup-Kupershmidt (KK) equation are presented. We successfully obtain more general exact travelling wave solutions for (2+ 1)-dimensional KK equation by the symmetry method and the (G1/G)-expansion method. Consequently, we find some new solutions of (2+1)-dimensional KK equation, including similarity solutions, solitary wave solutions, and periodic solutions. 相似文献
1000.
The π^+π^ transition of heavy quarkonia in decay ψ(2S) →π^+π^-J/ψ is studied. With the BESII data on the decay ψ(2S) →π^+π^-J/ψ, we update the values of coupling constants (gi) and chromopolarizability (αψ(2s)J/ψ) in this process. 相似文献