全文获取类型
收费全文 | 145篇 |
免费 | 23篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 40篇 |
金属工艺 | 3篇 |
机械仪表 | 3篇 |
建筑科学 | 3篇 |
能源动力 | 3篇 |
轻工业 | 14篇 |
石油天然气 | 2篇 |
无线电 | 7篇 |
一般工业技术 | 33篇 |
冶金工业 | 45篇 |
自动化技术 | 13篇 |
出版年
2023年 | 4篇 |
2022年 | 2篇 |
2021年 | 8篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 14篇 |
2017年 | 5篇 |
2016年 | 5篇 |
2015年 | 7篇 |
2014年 | 7篇 |
2013年 | 9篇 |
2012年 | 8篇 |
2011年 | 4篇 |
2010年 | 5篇 |
2009年 | 7篇 |
2008年 | 5篇 |
2007年 | 6篇 |
2006年 | 1篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 17篇 |
1997年 | 11篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1990年 | 1篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1976年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有168条查询结果,搜索用时 15 毫秒
1.
Mohamad A.A. Attia Roberto Orrù Francesco Delogu Selena Montinaro Sebastiano Garroni Emad M.M. Ewais Giacomo Cao 《Journal of the American Ceramic Society》2015,98(5):1453-1459
The effects produced by annealing Y2O3 nanopowders on their spark plasma sintering (SPS) behavior are systematically investigated in this work. It is found that the annealed powders display higher sinterability with respect to the as‐received ones. Indeed, the maximum densification level reached from pristine powders is about 97.5%, whereas density decreases when further increasing either the sintering temperature or the dwell time. In contrast, the density of SPS products obtained from pretreated powder monotonically increases with temperature and processing time, thus leading to fully dense materials in 30 min at 1050°C and 60 MPa. Correspondingly, it is found that the annealing treatment markedly inhibits grain coarsening during SPS. Thus, dense translucent samples with grain size below 100 nm can be attained from annealed powders. On the other hand, white‐opaque specimens with significantly coarser microstructures (up to 1‐μm‐sized grains) are obtained when pristine powders are directly processed under the same sintering conditions. Furthermore, it is observed that the annealing treatment of SPS samples in air allows for graphite contamination removal, whereas no improvement in term of light transmittance is produced. 相似文献
2.
Andrzej Malag Jacek Ratajczak Jerzy Gazecki 《Materials Science and Engineering: B》1993,20(3):332-338
Selective wet chemical etching of the AlxGa1−xAs/GaAs system has been applied to heterostructure characterization. Samples of LPE grown AlGaAs/GaAs laser double-heterostructures and separate confinement heterostructures as well as antiresonant reflecting optical waveguides heterostructures were treated with “I2 solution” (I2:KI:H2O) and hydrochloric acid. These compounds selectively etch the ternary AlxGa1−xAs layers, but with different “threshold composition” xth values (the x value is that above which the etching rate of a given compound increases sharply). Selectively etched samples have been examined by SEM. The experimental dependence of etching rate on the x value for I2 solution has been derived. From this dependence, the x composition of any ternary layer can be estimated simply. Observations were made of the “microscopic” properties of the heterostructure, such as the smoothness of the interfaces and the uniformity of layers. All imperfections resulting from the growth process, such as interface perturbations or compositional nonuniformity of layers, are clearly seen. An additional advantage of this etching technique is its simplicity. It allows quick examination of grown heterostructure for the selection of wafers for further processing. 相似文献
3.
4.
G Cantù N Pizzi F Mattavelli P Salvatori L Licitra CL Solero 《Canadian Metallurgical Quarterly》1998,18(3):135-142
This article introduces the basic principles of reading electrocardiograms (ECGs) for nurses who are unfamiliar with reading them. For more experienced practitioners there are a number of useful articles and books (e.g. Hampton, 1992a, b) that will help further their knowledge. The ECG records cardiac electrical activity as a graph; interpretation is illustrated here by sinus rhythm. A single ECG lead (lead II) is used throughout this article. Atrial fibrillation is described to show a contrasting dysrhythmia. Specific nursing care is suggested for patients being monitored or having ECGs taken. 相似文献
5.
Anna Galotta Enrico Giust Mauro Bortolotti Gian D. Sorarù Vincenzo M. Sglavo Mattia Biesuz 《Journal of the American Ceramic Society》2021,104(9):4329-4340
Diatomite, a natural silicate-based sedimentary rock, was densified by cold sintering at room temperature and 150°C under various pressures (100, 200, and 300 MPa) and using different NaOH water solutions (0–3 M). The relative density of cold sintered diatomite can be as high as 90%, a condition that can be achieved by conventional firing only at 1200–1300°C. The cold sintered materials maintain the same mineralogical composition of the starting powder (quartz, glass, and illite) and are constituted by well-deformed and flattened grains oriented orthogonally to the applied pressure. Conversely, an evident phase evolution takes place upon conventional firing with the formation of cristobalite and mullite. The bending strength of cold sintered artifacts can exceed 40 MPa and increases to ≈80 MPa after post-annealing at 800°C, such mechanical strength is much larger than that of conventionally pressed samples sintered at 800°C, which is only ≈1 MPa. 相似文献
6.
7.
Gian Domenico Sorarù Lakshminath Kundanati Balanand Santhosh Nicola Pugno 《Journal of the American Ceramic Society》2019,102(3):907-913
Silicon oxycarbide (SiOC) glasses in the form of thin, dense, and crack-free samples were fabricated according to the polymer pyrolysis route starting from cross-linked polysiloxane. The amount of free carbon in the final SiOC materials was varied in the range 18-60 vol%. The mechanical properties of the SiOC glasses were measured by nanoindentaion technique and revealed that both the Young's modulus and the hardness decrease with increase in the free carbon content and follow a simple rule of mixtures model. 相似文献
8.
Amir H. Tavakoli Renzo Campostrini Christel Gervais Florence Babonneau Joachim Bill Gian D. Sorarù Alexandra Navrotsky 《Journal of the American Ceramic Society》2014,97(1):303-309
The structure and properties of polymer‐derived Si–(B–)O–C glasses have been shown to be significantly influenced by the boron content and pyrolysis temperature. This work determined the impact of these two parameters on the thermodynamic stability of these glasses. High‐temperature oxide melt solution calorimetry was performed on a series of amorphous samples, with varying boron contents (0–7.7 at.%), obtained by pyrolysis of precursors made by a sol–gel technique. Thermodynamic analysis of the calorimetric results demonstrated that at a constant pyrolysis temperature, adding boron makes the materials energetically less stable. While the B‐containing glasses pyrolyzed at 1000°C were energetically less stable than the competitive crystalline components, increasing the pyrolysis temperature to 1200°C led to their enthalpic stability. 29Si and 11B MAS nuclear magnetic resonance (NMR) spectroscopy measurements on selected samples confirmed a decrease in the concentrations of mixed Si‐centered SOiC4?i and B‐centered BOjC3?j bonds at the expense of formation of SiO4 and B(OSi)3 species (indicating a tendency toward phase separation) when the boron content and pyrolysis temperature increased. In light of the findings from calorimetry and NMR spectroscopy, we propose a structure–energetic relationship in Si–(B–)O–C glasses. 相似文献
9.
10.
GP Rossi G Albertin S Bova AS Belloni F Fallo U Pagotto L Trevisi G Palù AC Pessina GG Nussdorfer 《Canadian Metallurgical Quarterly》1997,138(10):4421-4426