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11.
为研究钢管混凝土柱的轴向恢复力模型,设计制作了8个钢管混凝土柱试件并对其进行轴向往复加载,分析其受力机理和恢复力特性。基于试验结果,选用退化三线型模型,建立了钢管混凝土柱无量纲骨架曲线模型,并提出其轴拉与轴压方向的峰值承载力和位移的计算方法。鉴于钢管混凝土试件在轴拉与轴压方向受力机理的差异,对滞回曲线的正负向选用不同的滞回规则,建立了相应的卸载刚度函数。据此提出了钢管混凝土柱的轴向恢复力模型,并与试验滞回曲线进行对比,验证了恢复力模型的合理性,所建立的恢复力模型可为斜交网格结构体系的弹塑性分析提供依据。 相似文献
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In this study, undoped and Ag doped PbS thin films at different concentrations were deposited onto glass substrates at 225 °C by using ultrasonic spray pyrolysis technique, in order to investigate the effect of Ag doping on the physical properties of PbS thin films. Structural investigations revealed that all doped PbS:Ag thin films have cubic structure and Ag doping enhances crystalline level of PbS thin films. It was determined that average crystallite size of PbS:Ag thin films increased from 24 nm to 49 nm by increasing Ag doping concentration. Morphological studies showed that surfaces of the films become denser after Ag doping. Optical transmittance and absorption spectra revealed that all deposited thin films have low transmission and high absorbance within the visible region and band gap energy of the PbS:Ag thin films were determined to be in the range of 1.37 eV and 1.28 eV by means of optical method. Electrical conductivity type of PbS:Ag films was determined to be p-type and calculated electrical resistivity was found to be lowest for Ag-doped PbS thin films at 2%. 相似文献
14.
为深入认识ε晶型六硝基六氮杂异伍兹烷(ε-CL-20)分子的骨架内、外基团在升温过程中的结构演化规律,采用原位傅里叶变换红外光谱(in-situ FT-IR),结合差示扫描量热(DSC),对ε-CL-20骨架内外基团的温度响应规律进行了定量比较分析。结果表明,ε-CL-20骨架外基团(—NO_2、C—H)的红外吸收峰强度随温度升高经历了三个变化阶段:线性下降阶段(ZⅠ)、加速降低阶段(ZⅡ)和第二次加速降低阶段(ZⅢ),可分别对应于CL-20晶体热膨胀、热致相变与热分解过程;分子骨架内C—N伸缩振动同样经历上述三个阶段,但ZⅡ、ZⅢ区域起始温度均明显高于骨架外基团,表明无论是热致相变还是热分解过程,骨架外基团对温度都更为敏感,而在更高温度下,骨架内基团才会对温度产生响应;骨架内C—C伸缩振动的温度响应特点更为复杂:随着温度的升高,其峰强仅经历一次加速降低阶段,同时C—C伸缩振动出现与ε-γ相变密切相关的新特征峰,表明相变过程使得分子骨架内C—C键的振动模式发生了明显变化,进一步升温后发现新特征峰的面积相对占比在不断增加,说明这种骨架内振动模式的变化直至热分解结束前仍在不断进行。 相似文献
15.
模糊形态联想记忆网络FMAM具有较强的抗膨胀或腐蚀噪声能力,且可以模糊性解释。但抗混合噪声的能力很弱。而在实际中,随机噪声往往是混合型的,既有膨胀又有腐蚀噪声。为此提出了一种基于尺度空间的模糊形态联想记忆网络,并分析了其抗膨胀/腐蚀噪声和抗随机噪声的能力,它提高了自联想FMAM的抗随机噪声能力。通过仿真实验验证了该方法具有良好的性能。 相似文献
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针对大亚湾中微子实验中对掺钆液体闪烁体位置进行标定的需求,采用红外CCD摄像头对液位进行非接触无损检测,然后通过图像采集、图像预处理、图像分割、液位定位和液位测量等图像处理技术,实现对掺钆液体闪烁体位置的检测.文章在介绍整个红外CCD图像处理系统的同时,重点介绍了分段线性灰度拉伸算法、数字形态学等方法.实验结果表明,所提方法提高了被测液体位置的精确度,有效解决了当液闪存于底部位置以及金属环位置时无法准确测量液位的问题,并且满足误差在正负2 mm范围的实际要求. 相似文献
18.
We have studied two kinds of solder reactions between eutectic SnPb and Cu. The first is wetting reaction above the melting
point of the solder, and the second is solid state aging below the melting point of the solder. In wetting reaction, the intermetallic
compound (IMC) formation has a scallop-type morphology. There are channels between the scallops. In solid state aging, the
IMC formation has a layer-type morphology. There are no channels but grain boundaries between the IMC grains. Why scallops
are stable in wetting reactions has been an unanswered question of fundamental interest. We have confirmed that the scallop-type
morphology is stable in wetting reaction by re-wetting the layer-type IMC by molten eutectic SnPb solder. In less than 1 min,
a layer-type Cu6Sn5 is transformed back to scallops by the molten solder at 200 C. In analyzing these reactions, we conclude that the scallop-type
morphology is thermodynamically stable in wetting reaction, but the layer-type morphology is thermodynamically stable in solid
state aging, due to minimization of interfacial and grain boundary energies. 相似文献
19.
Time-of-Flight (ToF) sensors are popular devices that extract 3D information from a scene but result to be susceptible to noise and loss of data creating holes and gaps in the boundaries of the objects. The most common approaches to tackling this problem are supported by color images with good results, however, not all ToF devices produce color information. Mathematical morphology provides operators that can manage the problem of noise in single depth frames. In this paper, a new method for the filtering of single depth maps, when no color image is available, is presented, based on a modification to the morphological closing by reconstruction algorithm. The proposed method eliminates noise, emphasizing a high contour preservation, and it is compared, both qualitative and quantitatively, with other state-of-the-art filters. The proposed method represents an improvement to the closing by reconstruction algorithm that can be applied for filter depth maps of ToF devices. 相似文献
20.
Nowadays, license plate recognition for parking systems is a critical task to provide automatic control of customers and payment. This paper introduces a new method for automatic recognition of license plates of vehicles by mathematical morphology.The proposed method can provide the license plate number of the plates in different light conditions, colors,sizes, and inclination(angles). The algorithm can recognize the license plates of European Union vehicles quickly and correctly. The pattern learning of mathematical skeletons has high efficiency in the process. The performance of the algorithm is demonstrated well by the test in a parking control system. 相似文献