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51.
基于多相滤波器的信道化接收机及其应用研究 总被引:16,自引:0,他引:16
本文主要研究了应用多相滤波技术的信道化接收机建模问题。在给定信道频谱划分方案下,推导了基于多相 滤波器的信道化接收机数学模型。并由此模型设计了一个四信道模拟系统。最后用仿真实验结果验证了模型的正确性。 相似文献
52.
Yinghao Wu Linxiu Zhai Shouyu Xu Zhuo Han Xin Yuan Jinxi Wu 《Petroleum Science and Technology》2017,35(2):190-195
Shallow heavy oil is abundant but seriously biodegraded in Chepaizi Uplift and many biomarkers cannot be used effectively. Therefore, some new parameters and methods are used to analyze the biodegradation extent, classification, and oil–source of heavy oil samples. The acid value and group compositions are used to evaluate the biodegradation extent. Carbon isotopes are not only used to calculate the percentage of complex combined oil, but also to correlate oil–source in Chepaizi Uplift. δ13C of oil is used together with biomarkers that can bear serious degradation, such as pregnanes, tricyclic terpanes, and gammacerane. The crossplots of δ13C and biomarkers are effective correlation tools, such as the crossplot of δ13C and C21/C23 tricyclic terpanes. δ13C in different group compositions also show excellent oil–source correlation results. These methods to study biodegraded heavy oil are not only helpful to clarify the biodegradation extent of shallow heavy oil in an extensive area, but also effective to classify heavy oil and correlate oil–source. 相似文献
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Yufeng Cong Kejian Liao Wei Huang Yuchun Zhai 《Petroleum Science and Technology》2006,24(10):1187-1194
A dose of SBR modifier added to asphalt can improve asphalt's performance in stability, permanence, viscosity, and resistance to aging. Better application performances of asphalt pavement are affected directly by proper SBR modifying. This paper shows some investigations that confirm the relationship between the addition of SBR with the structure and the properties of SBR-modified asphalt. This paper also discusses the modified asphalt high temperature property, low temperature ductility, and mechanism of SBR-modified asphalt. The addition of SBR modifier showed an increase in viscosity, softening point, and elastic recovery of modified asphalt with rising temperature. When the temperature rises, the improvement of SBR-modified asphalt in softening point, elastic recovery, and visco-toughness result from SBR cross-linking. Although the lengths of low temperature ductility of SBR-modified asphalt are increased, the viscosities of modified asphalt increase; however, the softening point between the upper layer and lower layer were about 1.8°C after the isolated experiment. 相似文献
55.
旋冲钻井破岩力学模型的研究 总被引:4,自引:0,他引:4
旋冲钻井技术可有效提高硬地层、易斜地层的机械钻速。以弹性力学、波动理论和冲击动力学为基础,采用室内试验和力学理论相结合的研究方法,建立了旋冲钻井破岩力学模型。在该模型的建立过程中。首先根据冲击器的工作原理,结合冲击动力学,对旋,中钻井中冲击动载作用下的破岩过程进行了简化;假设岩石为弹性介质,根据弹性力理论,分析了轴向力和剪切力作用下岩石的受力状态;对在室内进行的载荷侵入深度曲线的试验结果进行分析,得出岩石所受外栽荷与侵入深度成一定的线性关系;结合波动理论,分析了冲击动栽作用下岩石的应力状态。建立的破岩力学模型对旋冲钻井的进一步发展具有重要的现实意义。 相似文献
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提出了一种光探测器芯片小信号等效电路模型及其建立方法.首先根据光探测器的物理结构确定其等效电路模型,模型考虑了影响光探测器高频性能的主要因素.然后精确测量了光探测器芯片的S参数,通过遗传算法对测量的S参数进行拟合,最终计算出模型的各个参量.在130MHz~20GHz范围内的实验结果表明,模型仿真结果与测量结果相吻合,证明了建模方法的可靠性.该模型有效地模拟了光探测器芯片的高频特性,利用该模型可以对光探测器及相应光电集成器件进行电路级仿真和优化. 相似文献
58.
Hao‐Jie Zhang Kai‐Xue Wang Xue‐Yan Wu Yan‐Mei Jiang Yu‐Bo Zhai Cheng Wang Xiao Wei Jie‐Sheng Chen 《Advanced functional materials》2014,24(22):3399-3404
Instead of carbon, Mo2C is used to modify the MoO2 material for the first time. The presence of highly conductive and electrochemical inactive Mo2C decreases the resistance of the charge transport and enhances the structural stability of MoO2 nanoparticles upon lithiation and delithiation, ensuring the superior cycling stability and high rate capability of the heteronanotubes. Cycled at 200 and 1000 mA g?1 for 140 cycles, the discharge capacities of the MoO2/Mo2C heteronanotubes remain to be 790 and 510 mAh g?1, respectively. This work demonstrates the potential of the novel heteronanotubes for application as an electrode material for high‐performance Li‐ion batteries. 相似文献
59.
Ziying Hu Xuming Zhang Zhaoyue Liu Kaifu Huo Paul K Chu Jin Zhai Lei Jiang 《Advanced functional materials》2014,24(40):6381-6388
Bioinspired surfaces with special wettability have attracted a significant attention in recent years because of their potential applications for no loss liquid transfer, anti‐icing, and self‐cleaning. Herein, the realization of two extreme superhydrophobic states on 1H, 1H, 2H, 2H–perfluorooctyltriethoxysilane‐modified TiO2 nanotube arrays (NTAs) is described by changing the structural characteristics of nanotubes while keeping the surface chemical composition constant. The water adhesive force is regulated in a wide range from ≈4.4 to ≈89.6 μN by the nanotubular diameter, length, density, and surface roughness. The cooperation effect between the negative pressures induced by the volume change of sealed air‐pockets and the van der Waals' attraction at solid–liquid interface contributes to the water adhesion. The superhydrophobic TiO2 NTAs with a high adhesive force is used as a “mechanical hand” to transfer water microdroplets without any loss, and the one with extremely low adhesive force is utilized as a self‐cleaning and anti‐icing surface. 相似文献
60.