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21.
磁敏智能软材料是一类将微米或纳米尺度的磁性颗粒分散在不同基体中制备而成的多功能复合材料.由于其流变性能在外磁场的调控下可以实现连续、快速、可逆的改变,因此在建筑、振动控制和汽车工业等领域得到了广泛地应用.本文首先介绍了磁敏智能软材料发展历史及分类,分析了不同种类的磁敏智能软材料的特点和存在的科学问题;然后从实验和理论两个方面讨论了磁流变机理的研究现状;最后从实际应用的角度对这类材料未来的发展方向进行了展望.  相似文献   
22.
小波变换特征提取的复合材料损伤检测   总被引:3,自引:0,他引:3  
论述了小波变换及其快速算法,基于小波变换的波形模量极大点来构造全局的相似性度量,并将此应用于复合材料损伤类型的检测  相似文献   
23.
复合材料层合板面内压阻效应层合理论研究   总被引:1,自引:0,他引:1       下载免费PDF全文
肖军  李勇 《固体力学学报》1999,20(2):157-163
应用经典层合板理论和静电学理论,研究了正交异性介质的电导率,压导系数和压阻系数的特性,导出了Cauchy应变空间中压阻系数与压导系之间的关系;建立了平面应力状态下层合板面内压阻效应的层合理论。  相似文献   
24.
压电材料在智能结构形状和振动控制中的应用   总被引:11,自引:0,他引:11       下载免费PDF全文
综述了压电材料在智能结构形状和振动控制中的应用.基于大量国内外有关压电介质的文献,对在分布的压电材料的表面建立力学特性与电学特性的一一对应关系,以及与之对应的分布感测、分布控制理论和混合控制理论,作了全面阐述.首先概述了研究压电材料的重要意义,然后介绍了压电本构关系和有关压电板壳的力学理论和控制理论.着重阐述了研究压电结构的数值方法与实验.展望了该领域今后的研究方向.  相似文献   
25.
含ER流体板结构的振动特性研究   总被引:8,自引:0,他引:8  
本文制作了含电流变体夹层梁和模拟飞机蒙皮结构的含电流变体加筋层合板,采用响应幅频法,测试了在不同电场强度梁和层合加筋板结构各阶固有频率和振幅的变化;并着重测试了加筋层合板结构在改变板材料、电流变体作用面积等条件时各阶频响特性的变化。实验结果表明,随着电场强度的增加,夹层梁的频响特性有很大变化;而层合板的固有频率变化不大,但振幅却有显著变化,其中铝-层合加筋板的频响幅值的变化率达到50.1%。  相似文献   
26.
智慧城市建设背景下各类组织的信息安全服务需求逐步提升。为提升政府应对智慧城市信息安全服务质量问题的监管效用,构建了由政府和智慧城市信息安全服务提供方组成的演化博弈模型。我们考虑了用户参与,并探讨了不同奖惩机制下的博弈演化策略。最后,借助Matlab2021b分析了最优机制下关键参数上限值提高对博弈主体策略选择概率的影响。分析结果表明:静态奖惩机制下的系统不存在稳定点,动态奖励与静态惩罚、动态奖励与动态惩罚、静态奖励与动态惩罚的系统存在稳定点,且动态奖励与静态惩罚相较于其他机制为更优机制。通过调控奖励上限值、惩罚上限值和用户反馈概率,从政府和用户两个角度提出了针对性的策略建议。  相似文献   
27.
    
Ferroelectric photo-thermochromic (PTC) materials with both high coloration contrast and high transparency have attracted great attention for their applications in “smart window” for non-contact optical information storage. Nevertheless, it has been challenging to develop a ferroelectric PTC material that simultaneously meets the distinct transparency and coloration contrast requirements. Herein, dual rare-earth ions doping of 1%Er-(K0.5Na0.5)0.985La0.015NbO6 (Er-KNLN) ferroelectric ceramics is aimed at increasing the optical transmittance and obtaining an ideal coloration contrast. The traditional solid-state reaction is exploited for ceramics fabrication, and the optimal optical transmittance (≈70% at 900 nm) can be obtained due to finer grains, more symmetrical structure, and compact structure in samples sintered at a suitable temperature (such as ≤1165 °C). Contributed from the trapping and de-trapping of charge carriers in vacancy-related defects, the Er-KNLN ceramics exhibit obvious PTC behavior and the novel impedance modulation is developed. The coupling between PTC behavior and optical transparency, lanthanide up-conversion emission, patterned display, and room temperature impedance enables nondestructive rewritable and readout characteristics of multi-mode “0” and “1” states. This work solves the main problems hampering the promising applications of ferroelectric materials and paves a way for developing multifunctional optical memory smart windows.  相似文献   
28.
    
Here the relation between digestion of proteins by trypsin covalently bound to paper and trypsin in-solution is investigated. The trypsin acting on paper is covalently bound. A trypsin concentration of 0.5% (w/v) results in the highest digestion activity of all concentrations tested. Additionally, it can be seen that trypsin on-paper has retained approx. 50% of its activity. Unlike trypsin in-solution, the stability of the smart proteolysis samplers was regarded to be stable for at least four months when kept refrigerated. Autolysis was very small for covalently bound trypsin: less than 2% compared to in-solution trypsin. Proteomic analysis of diluted human serum showed more protein identifications (214) in-solution digestions than on-paper digestions (76). Also, higher coverage for the in-solution digestion was obtained. Those proteins identified after on-paper digestion with no or few disulfide bonds seem to have more similar sequence coverages compared to those identified after in-solution digestion. Smart samplers allow the determination of at least 70–75 proteins without performing the overnight digestion. All in all, trypsin covalently bound to paper shows to retain high proteolytic activity and is a stable alternative for conventional digestions. In this way, smart proteolytic samplers show their feasibility in pre-lab sample preparation.  相似文献   
29.
    
Smart windows with adjustable transmittance via physical stimuli are eagerly desired for sorts of energy-saving lighting systems. However, reciprocal trade-off relationship such as high transparency and coloration/discoloration ability exists in smart windows, not conducive to optical-electrical coupling and leap in performance. Substituting for common composites utilized in smart windows, here, single transparent ceramic-based smart windows are reported through composition design and defect management strategies to regulate the optoelectronic performances and break off the contradictions between optical transmittance, photo-thermochromism and electrical conductivity. By first principles calculations and precisely tuning Er3+, Ba2+, Sr2+ concentrations in non-stoichiometric Er-doped (K0.5Na0.5)NbO3-(Ba, Sr)TiO3, the fabricated ceramics exhibit brilliant transparency and multi-mode dramatical and reversible modulations of pellucidity, photoluminescence intensity, along with conductivity (over fivefold variation), enabling prominent optoelectronic information storage and modulating capacity in vivid potential applications, such as easy-readout/erasable optical memorizers, photo-memristors and anti-counterfeiting displays.  相似文献   
30.
    
Additive manufacturing (AM), otherwise known as three‐dimensional (3D) printing, is driving major innovations in many areas, such as engineering, manufacturing, art, education, and medicine. Although a considerable amount of progress has been made in this field, additional research work is required to overcome various remaining challenges. Recently, one of the actively researched areas lies in the AM of smart materials and structures. Electroactive materials incorporated in 3D printing have given birth to 4D printing, where 3D printed structures can perform as actuating and/or sensing systems, making it possible to deliver electrical signals under external mechanical stimuli and vice versa. In this paper, we present a lightweight, low cost piezoelectric material based on the dispersion of inorganic ferroelectric submicron particles in a polymer matrix. We report on how the proposed material is compatible with the AM process. Finally, we discuss its potential applications for healthcare, especially in smart implants prostheses. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 109–115  相似文献   
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