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961.
962.
针对军事目标红外图像信噪比低、NAS-RIF算法复原模糊图像时敏感于噪声的缺陷,提出一种基于Contourlet多尺度变换去噪和图像细节规整化的改进NAS-RIF盲复原算法。首先,通过Contourlet变换对图像进行去噪预处理;然后,利用最优阈值分割技术提取目标的可靠支持域,并引入规整化方法,在代价函数中添加目标边缘保持约束项,保存图像细节特征;最后,利用共轭梯度(CG)算法优化代价函数,以保持算法的收敛速度。两组实验的结果表明,针对信噪比较低的气动红外退化图像,与原始NAS-RIF方法相比,本文提出的改进算法具有更好的复原效果,算法的收敛速度基本保持不变。 相似文献
963.
964.
在LFMCW测距雷达中,差频信号测频是否精确关系到整个雷达系统的测距精度。该文分析了在LFMCW测距雷达中精确测频的难度,提出了基于FPGA的变频采样算法。该算法采用VerilogHDL在ISE平台上编写,通过了Modelsim仿真验证。该算法与其他精确算法相比,具有实现简单,占用FPGA资源少,测频误差小的优点,有一定的工程实现价值。 相似文献
965.
The drive towards shorter design cycles for analog integrated circuits has given impetus to the development of Field Programmable Analog Arrays (FPAAs), which are the analogue counterparts of Field Programmable Gate Arrays (FPGAs). In this paper, we present a new design methodology which using FPAA as a powerful analog front-end processing platform in the smart sensory micro- system. The proposed FPAA contains 16 homogeneous mixed-grained Configurable Analog Blocks (CABs) which house a variety of processing elements especially the proposed fine-grained Core Con- figurable Amplifiers (CCAs). The high flexible CABs allow the FPAA operating in both continu- ous-time and discrete-time approaches suitable to support variety of sensors. To reduce the nonideal parasitic effects and save area, the fat-tree interconnection network is adopted in this FPAA. The functionality of this FPAA is demonstrated through embedding of voltage and capacitive sensor signal readout circuits and a configurable band pass filter. The minimal detectable voltage and capacitor achieves 38 uV and 8.3 aF respectively within 100 Hz sensor bandwidth. The power consumption comparison of CCA in three applications shows that the FPAA has high power efficiency. And the simulation results also show that the FPAA has good tolerance with wide PVT variations. 相似文献
966.
Mn3O4资源丰富、结构稳定,具有较高的理论电容,是一种较有潜力的超级电容器材料,但其较差的导电性却阻碍了其在这方面应用。本论文以实心ε-MnO2微米粉体和具有亲水性的GO粉体为原料,在去离子水中通过磁力搅拌和冷冻干燥制备出具有良好接触的MnO2/GO复合粉体。然后经一步氢气还原处理,使实心ε-MnO2和GO同步转化为具有纳米多孔结构的多孔Mn3O4和RGO,从而获得分散均匀、具有高比表面积和优良导电性的高性能Mn3O4/RGO复合粉体。经电化学测试可知,Mn3O4/RGO复合粉体在2 mV/s的扫描速率下的比电容为25.2 F/g且具有较好的电容留存率。 相似文献
967.
Humidity‐Triggered Self‐Healing of Microporous Polyelectrolyte Multilayer Coatings for Hydrophobic Drug Delivery
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Xia‐Chao Chen Ke‐Feng Ren Jia‐Hui Zhang Dan‐Dan Li Emily Zhao Zhong Jonathon Zhao Zhi‐Kang Xu Jian Ji 《Advanced functional materials》2015,25(48):7470-7477
Layer‐by‐layer (LbL) self‐assemblies have inherent potential as dynamic coatings because of the sensitivity of their building blocks to external stimuli. Here, humidity serves as a feasible trigger to activate the self‐healing of a microporous polyethylenimine/poly(acrylic acid) multilayer film. Microporous structures within the polyelectrolyte multilayer (PEM) film are created by acid treatment, followed by freeze‐drying to remove water. The self‐healing of these micropores can be triggered at 100% relative humidity, under which condition the mobility of the polyelectrolytes is activated. Based on this, a facile and versatile method is suggested for directly integrating hydrophobic drugs into PEM films for surface‐mediated drug delivery. The high porosity of microporous film enables the highest loading (≈303.5 μg cm?2 for a 15‐bilayered film) of triclosan to be a one‐shot process via wicking action and subsequent solvent removal, thus dramatically streamlining the processes and reducing complexities compared to the existing LbL strategies. The self‐healing of a drug‐loaded microporous PEM film significantly reduces the diffusion coefficient of triclosan, which is favorable for the long‐term sustained release of the drug. The dynamic properties of this polymeric coating provide great potential for its use as a delivery platform for hydrophobic drugs in a wide variety of biomedical applications. 相似文献
968.
Wei Hu Zhi Ren Junpeng Li Erin Askounis Zhixin Xie Qibing Pei 《Advanced functional materials》2015,25(30):4827-4836
Dielectric elastomers have been widely investigated for muscle‐like soft actuators and capacitive sensors. Mechanical properties play a central role in the performances of the active material. Most elastomers have specific moduli pre‐determined by the polymers' molecular structures, which are not suitable for applications in changing working conditions as natural muscles are capable of. Here new dielectric elastomers are described exhibiting variable moduli controlled via thermal treatment. The elastomers contain furan‐maleimide Diels–Alder adduct moieties to administer the crosslinking densities of the elastomeric networks via reversible Diels–Alder/retro‐Diels–Alder cycloaddition reaction, resulting in changes in the elastomers' moduli. One of the synthesized elastomers has moduli that can be controlled between 0.17 and 0.52 MPa incrementally and reversibly. Capacitive strain sensors based on this elastomer can be operated in both rigid and soft modes to achieve variable sensing response up to 30% linear strain. Actuators were fabricated and operated in both high strain mode (35% actuation area strain at 65 MV m?1) and high force output mode (0.55 MPa at 104 MV m?1). The elastomers can exhibit a range of stress–strain outputs in similar fashion as muscle. 相似文献
969.
970.