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1.
一种用于岩石材料微裂纹观察的复型技术 总被引:3,自引:6,他引:3
介绍了一种用于岩石材料微裂纹观察的复型技术。这种半透明的试样表面复型可有效复制宽度大于0.2μm的微观裂纹以及矿物颗粒的微结构特征,并可方便地用于光学显微镜和扫描电镜下观察。它的最大特点是不仅能精确复制岩样的表面裂纹,同时还能提供足够多的信息以鉴别矿物颗粒。应用表明:对于岩石材料的微破裂研究,特别对于矿物颗粒的破坏行为与岩石破坏的关系研究,它是一种方便而有效的方法。 相似文献
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Rong Hua Zhang De An Shi Chi Pong Tsui Chak Yin Tang Sie Chin Tjong Robert Kwok Yiu Li 《Polymer Engineering and Science》2011,51(2):403-410
Compatibilized polypropylene (PP)/polyamide (PA6) blends with and without β nucleating agent (β‐NA) are prepared, and are designated as Blend‐0.3 and Blend‐0, respectively. The melting and crystallization characteristic of the blends crystallized under different cooling rates and different crystallization temperatures are studied. It is observed that high β‐PP content can be developed in Blend‐0.3 only at slow cooling rates (<5°C/min), whereas high α‐PP content is formed at fast cooling rates. Isothermal crystallization analysis of Blend‐0 indicates that PA6 is an effective NA for α‐PP in the lower temperature range, whereas the α‐nucleating effect disappears in the higher temperature range. Blend‐0.3 can, therefore, be viewed as a system containing both α‐ and β‐NAs, simultaneously. PA6 is competing with β‐NA in inducing PP crystallization. Under the normal injection of Blend‐0.3, the melt will be cooled through the higher temperature that favors the effectiveness of β‐NA rapidly because of the faster cooling rate. However, the α‐nucleation effect from PA6 predominate at the lower temperature. This explains the difficulty in obtaining high β‐PP content in Blend‐0.3 from injection molding. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers 相似文献
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In this paper, we study a versatile iterative framework for the reconstruction of uniform samples from nonuniform samples
of bandlimited signals. Assuming the input signal is slightly oversampled, we first show that its uniform and nonuniform samples
in the frequency band of interest can be expressed as a system of linear equations using fractional delay digital filters.
Then we develop an iterative framework, which enables the development and convergence analysis of efficient iterative reconstruction
algorithms. In particular, we study the Richardson iteration in detail to illustrate how the reconstruction problem can be
solved iteratively, and show that the iterative method can be efficiently implemented using Farrow-based variable digital
filters with few general-purpose multipliers. Under the proposed framework, we also present a completed and systematic convergence
analysis to determine the convergence conditions. Simulation results show that the iterative method converges more rapidly
and closer to the true solution (i.e. the uniform samples) than conventional iterative methods using truncation of sinc series. 相似文献
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A new method is given for designing multivariate control charts based on loss functions. The average run length contours of the proposed procedure correspond closely to the contours of the expected loss. The approach is much more efficient in terms of resulting statistical properties than the method of Mohebbi and Hayre (1989). Several bivariate examples are considered. 相似文献
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In this study, pure rhodium was fabricated and mechanically investigated at the nanoscale for the first time. The nanopillars approach was employed to study the effects of size on the yield point. Nanopillars with different diameters were fabricated using electroplating followed by uniaxial compression tests. Scanning electron microscopy (SEM) was used as a quality control technique by imaging the pillars before and after compression to ensure the absence of cracks, buckling, barrelling or any other problems. Transmission electron microscopy and SEM were used as microstructural characterization techniques. Due to substrate-induced effects, only the plastic region of the stress–strain curves were investigated, and it was revealed that the yield point increases with size reduction up to certain limit, then decreases with further reduction of the nanopillar size (diameter). The later weakening effect is consistent with the literature, which demonstrates the reversed size effect (the failure of the plasticity theory) in nanocrystalline metals, i.e. smaller is weaker. In this study, however, the effect of size reduction is not only weakening, but is strengthening-then-weakening, which the authors believe is the true behavior of nanocrystalline materials. 相似文献
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Physical and mathematical models of strength behaviour to explain the angle-of-bias effects postulated in Part I are further examined and various modifications suggested. Comparison between experimental results on a wide range of woven fabrics and theoretical predictions with the basic model and its modifications is made, and a good fit between experimental results and theoretical predictions is found and described. 相似文献
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