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81.
A new surface micromachining way of ultrashort plus laser for C/SiC composites with high quality and efficiency was demonstrated, including picosecond and femtosecond laser. Surface morphologies, element content and bonding states of C/SiC composites were analysed in detail after machined by picosecond and femtosecond laser power respectively. For femtosecond laser machining, the amount of nanoparticles increased with increasing laser power. At 20 and 50?mW, Si–C, C–C and Si–O bonds existed in nanoparticles, while Si–C bonds disappeared at 70?mW. For picosecond laser machining, cauliflower-like particles and periodic ripple with certain depth were formed distinctly. Furthermore, thermal ablation phenomenon occurred, and only Si–O bonds existed in particles due to the oxidation of the carbon fibres and SiC matrix. The results showed that femtosecond laser with low power was more suitable to the surface machining due to better machining quality and less machining damage compared with high power picosecond laser. 相似文献
82.
住宅钢结构发展的相关技术问题 总被引:2,自引:0,他引:2
通过工程实践,探索了多层钢结构住宅建筑技术和与之相配套的保温节能墙体、楼板、屋面板材等的设计理念及其关键技术问题。 相似文献
83.
《Food Control》2016
Foods with high added value, such as Iberian dry-cured products, are susceptible to fraud. Many attempts have been made to differentiate the commercial/quality categories of Iberian dry-cured hams by analytical determinations. However, as discrimination by such means is not fully reliable, legislation to prevent fraudulent practice is based on administrative controls and certification. Here, new analytical approaches based on ultrahigh resolution mass spectrometry (UHRMS) and crystallographic techniques applied to the lipid fraction, in combination with chemometrics, are studied. The results of the triacylglycerol profile determined by UHRMS and the fingerprint provided by the thermograms obtained by differential scanning calorimetry offer the promise of analytic discrimination of Iberian dry-cured ham categories. In addition, these determinations, in combination with chemometrics, may prove extremely useful to authenticate many foods containing high to moderate amounts of lipids. 相似文献
84.
Xiuying Yang Amir Hamidzadeh Mohammad Ilkhani Amin Foroughi Mohammad Javad Esfahani 《Petroleum Science and Technology》2016,34(17-18):1530-1533
Gasification is a clean technology to convert fuels to high-quality syngas in presence of a gasifying agent. In this study, an Aspen Plus model of heavy oil gasification was developed to produce the hydrogen rich syngas. Effect of some parameters such as gasification temperature and steam/fuel ratio on the hydrogen yield and was investigated. Results showed that the temperature plays a major role in the process; higher temperatures produce the higher hydrogen content. It was also found that the operation under high steam/fuel ratio can cause a significant increase in the hydrogen yield. The modeling results were compared with the experimental data available in the literature and found to be in good agreement. 相似文献
85.
86.
《International Journal of Hydrogen Energy》2020,45(55):30101-30112
The influences of two types of heat-treatments on the corrosion behavior of 316L SS in the simulated cathodic environment of PEMFC, are investigated using potentiodynamic curve, electrochemical impedance spectroscopy (EIS), Mott-Schottky plot and auger electron spectroscopy (AES), respectively. The results show that 316L SS is in the passive state within the potential region from −0.1VSCE to 0.8VSCE in the simulated cathodic environment of PEMFC, and a passive film can be formed on 316L SS. The passivity of 316L SS in the simulated cathodic environment of PEMFC firstly increases and then degrades with the increased solid solution temperature or time, and the best passivity corresponds to the solid solution temperature at 1050 °C for 40 min among other solid solution treatments. While 316L SS heat-treated with the solid solution treatment at 1050 °C for 40 min plus aging treatment at 900 °C for 4 h, also has the best passivity in the same solution among other solid solution plus aging treatments. The best corrosion protection, lowest donor density and the highest thickness of the passive film corresponding to the solid solution temperature at 1050 °C for 40 min among other solid solution or solid solution plus aging heat treatments, and this treatment is mostly suitable for improving the anti-corrosion property of 316L SS in the simulated cathodic environment of proton exchange membrane fuel cell (PEMFC). 相似文献
87.
88.
This paper shows how to apply generalized eigenvalue minimization to processes that can be described by a first-order plus time-delay model with uncertain gain, time constant and delay. An algorithm to transform the uncertain first-order plus time delay model into a state-space model with uncertainty polyhedron is firstly described. The accuracy of the transformation is studied using numerical examples. Then, the uncertainty polyhedron is rewritten as a linear-matrix-inequality constraint and generalized eigenvalue minimization is adopted to calculate a feedback control law. Case studies show that even if uncertainties associated with the first-order plus time delay model are significant, a stable feedback control law can be found. The proposed control is tested by comparing with a robust internal model control. It is also tested by applying it to the temperature control of air-handing units. 相似文献
89.
90.
《Signal Processing: Image Communication》2014,29(3):316-331
In multiview video plus depth (MVD) format, virtual views are generated from decoded texture videos with corresponding decoded depth images through depth image based rendering (DIBR). 3DV-ATM is a reference model for the H.264/AVC based multiview video coding (MVC) and aims at achieving high coding efficiency for 3D video in MVD format. Depth images are first downsampled then coded by 3DV-ATM. However, sharp object boundary characteristic of depth images does not well match with the transform coding based nature of H.264/AVC in 3DV-ATM. Depth boundaries are often blurred with ringing artifacts in the decoded depth images that result in noticeable artifacts in synthesized virtual views. This paper presents a low complexity adaptive depth truncation filter to recover the sharp object boundaries of the depth images using adaptive block repositioning and expansion for increasing the depth values refinement accuracy. This new approach is very efficient and can avoid false depth boundary refinement when block boundaries lie around the depth edge regions and ensure sufficient information within the processing block for depth layers classification. Experimental results demonstrate that the sharp depth edges can be recovered using the proposed filter and boundary artifacts in the synthesized views can be removed. The proposed method can provide improvement up to 3.25 dB in the depth map enhancement and bitrate reduction of 3.06% in the synthesized views. 相似文献