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991.
用于GaAs功率MESFET的新型钝化膜 总被引:3,自引:0,他引:3
用直流反应溅射淀积的AlN薄膜对GaAs功率MESFET进行了钝化。给出了钝化后器件的直流特性。器件的直流参数BVGD、IDSS和Vp在钝化后几乎没有改变。还给出了器件的微波特性。实验证明,AlN钝化的器件性能较好,它是一种很有前途的GaAs钝化材料。 相似文献
992.
993.
《Progress in Solid State Chemistry》2014,42(4):157-174
The impact of different formulation methods, involving related process technologies, as well as the influence of dispersing intensity on the structural and electrical coating layer properties of LiMn2O4/LiNi0,80Co0,15Al0,05O2 (LMS/NCA) blends are studied. Findings are finally correlated with the electrochemical rate-capability in order to derive process-structure–property functions to facilitate systematical electrode development. LMS was found to be sensitive according mechanical stress but by processing LMS/NCA blend electrodes this problem can be avoided. In general carbon black (CB) agglomerate size and its distribution in the binder network were identified to be significant factors influencing rate-capability. Both were found to influence pore structure by utilizing representative low and high energy methods for the formulation of the suspensions. The specific pore volume in the pore size region of 10 μm ≥ dp ≥ 0.5 μm was discovered to strongly influence rate-capability. These highways for lithium-ion transport allow for higher mass of lithium-ions per unit time penetrating into the inner surface of the coating layer. Specific volume and thus rate-performance can either be increased by a binder solution based formulation method or by decreasing the specific energy input during dispersing process. Hence no superior formulation method exists. The adjustment of mixing intensity and therewith the achieved CB agglomerate size, referring to the formulation method used, is essential. Thus comparable electrochemical rate performance was found for the same specific volume of approximately 0.25 cc g−1 but for different dispersing intensities. Further, the pore size region of 1.5 μm > dp > 0.03 μm was identified to be characteristic for the CB agglomerate size and the corresponding CB treatment method used. Peakedness of the pore size distribution was found to follow electrode conductivity which was the largest for a distributive dry mixing method. For electrodes showing a good CB agglomerate distribution in the binder network rate-capability was found to be limited by the pore structure of the coating layer and, thus, preliminarily by the corresponding ion transport kinetic. Based on the findings a model concept on processes occurring during dispersing was proposed and discussed to describe viscosity evolution over dispersing time. 相似文献
994.
Molecular aggregates in conjugated polymer(CP) solution can propagate into mesoscale morphology of the relevant film and further dominate the optoelectronic property. Herein, we probed the aggregation behavior of poly(9,9-dioctylfluorene-2,7-diyl)(PFO) and studied its influence on the photophysical property in 1,2-dichloroethane(DCE) solution, where the contents of β-phase or-aggregates increased with prolonged aging time. Thereinto, high quality β-film was fabricated from DCE solution with critical aggregate time of 6 min. The film exhibited excellent surface morphology and characteristic emission of β-phase. Meanwhile, films prepared from aged DCE solutions exhibited high crystallinity, which was promising to obtain higher photoluminance efficiency and charge transport ability simultaneously. Therefore, it is significant to get deep insight into the aggregation behavior of CP, which is involved not only with the solution-processing technology of plastic device, but also with the optoelectronic property of CP. 相似文献
995.
996.
997.
利用定量相场模型研究了强各向异性、表面吸附率以及界面动力学作用条件下六方Ga N螺旋结构的表面形貌与生长机理.通过引入小面相各向异性的相场修正方程,研究了不同各向异性的稳态螺旋形貌,发现各向异性通过改变台阶尖端的曲率作用影响螺旋生长.弱各向异性下稳态螺距及界面动力学特征相对稳定,各向异性较强时尖端的过饱和度随着各向异性的增强而增大,并使得界面平衡态向着有利于螺旋台阶推进的方向移动.研究了表面吸附率对小面相螺旋生长的作用机理,发现吸附率的增加导致了稳态螺旋间距的降低,通过分析螺旋间距随台阶宽度的变化趋势,发现增强的表面吸附和各向异性强度降低了螺旋间距的收敛性,并且具体分析了收敛性误差;通过探讨界面动力学作用条件下螺旋形貌特征以及螺旋间距变化趋势,发现界面动力学系数通过改变稳态螺旋间距与特征指数因子调控螺旋生长的动力学机理,与各向同性相比小面相螺旋生长表现出较低的界面动力学系数依赖性. 相似文献
998.
Yumeng Xu Dr. Xing Guo Prof. Zhenhua Lin Qingrui Wang Prof. Jie Su Prof. Jincheng Zhang Prof. Yue Hao Prof. Keke Yang Prof. Jingjing Chang 《Angewandte Chemie (International ed. in English)》2023,62(33):e202306229
Perovskite solar cells (PSCs) are considered as a promising photovoltaic technology due to their high efficiency and low cost. However, their long-term stability, mechanical durability, and environmental risks are still unable to meet practical needs. To overcome these issues, we designed a multifunctional elastomer with abundant hydrogen bonds and carbonyl groups. The chemical bonding between polymer and perovskite could increase the growth activation energy of perovskite film and promote the preferential growth of high-quality perovskite film. Owing to the low defect density and gradient energy-level alignment, the corresponding device exhibited a champion efficiency of 23.10 %. Furthermore, due to the formation of the hydrogen-bonded polymer network in the perovskite film, the target devices demonstrated excellent air stability and enhanced flexibility for the flexible PSCs. More importantly, the polymer network could coordinate with Pb2+ ions, immobilizing lead atoms to reduce their release into the environment. This strategy paves the way for the industrialization of high-performance flexible PSCs. 相似文献
999.
Jiaqi Tang Dr. Zuozhong Liang Haonan Qin Xiangquan Liu Binbin Zhai Zhen Su Qianqian Liu Dr. Haitao Lei Prof. Dr. Kaiqiang Liu Prof. Dr. Chuan Zhao Prof. Dr. Rui Cao Prof. Dr. Yu Fang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(1):e202214449
Synthesizing large-area free-standing covalent organic framework (COF) films is of vital importance for their applications but is still a big challenge. Herein, we reported the synthesis of large metalloporphyrin-based COF films and their applications for oxygen electrocatalysis. The reaction of meso-benzohydrazide-substituted metal porphyrins with tris-aldehyde linkers afforded free-standing COF films at the liquid-air interface. These films can be scaled up to 3000 cm2 area and display great mechanical stability and structural integrity. Importantly, the Co-porphyrin-based films are efficient for electrocatalytic O2 reduction and evolution reactions. A flexible, all-solid-state Zn-air battery was assembled using the films and showed high performance with a charge–discharge voltage gap of 0.88 V at 1 mA cm−2 and high stability under bent conditions (0° to 180°). This work thus presents a strategy to synthesize functionalized COF films with high quality for uses in flexible electronics. 相似文献
1000.
Continuous mullite ceramic fibers were fabricated by a sol–gel dry spinning technique. The sol was prepared from an aqueous
solution of aluminum nitrate (AN), aluminum isopropoxide (AIP) and tetraethylorthosilicate (TEOS). The sol–gel transition
was investigated by measuring the volume, the solid content, the viscosity and the rheological properties of the solution.
Shear viscosity η of the mullite sol varied dynamically with concentrating time and temperature. Combine size analysis of
sol particles and TEM analysis on this basis, the growth character of sol particles agglomeration and its structural evolution
were discussed. By adjusting the temperature, the gelling degree could stabilize at a certain value and the sol–gel transition
could be transferred to the spinning line. Continuous fibers were spun from such sols immediately before gelling in a laboratory
dry spinning apparatus. The spinneret contained thirty circular holes, each having a diameter of 0.2 mm. The temperature inside
the spinning channel was 100–120 °C, the winding speed was 100–300 m/min. Sintering of the precursor fibers at 1,100 °C yields
crack-free mullite ceramic fibers. 相似文献