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1.
Xuewu Li Lin Zhang Tian Shi Weining Yu Jinhui Shao Xuegang Zhou Yuxing He Binbin Zhang 《工业材料与腐蚀》2021,72(5):951-959
Ti-based amorphous metallic glasses have excellent mechanical, physical, and chemical properties, which is an important development direction and research hotspot of metal composite reinforcement. As a stable, simple, efficient, and large-scale preparation technology of metallic powders, the gas atomization process provides an effective way of preparing amorphous metallic glasses. In this study, the controllable fabrication of a Ti-based amorphous powder, with high efficiency, has been realized by using gas atomization. The scanning electron microscope, energy-dispersive spectrometer, and X-ray diffraction are used to analyze surface morphology, element distribution, and phase structure, respectively. A microhardness tester is used to measure the mechanical property. An electrochemical workstation is used to characterize corrosion behavior. The results show that as-prepared microparticles are more uniform and exhibit good amorphous characteristics. The mechanical test shows that the hardness of amorphous powder is significantly increased as compared with that before preparation, which has the prospect of being an important part of engineering reinforced materials. Further electrochemical measurement shows that the corrosion resistance of the as-prepared sample is also significantly improved. This study has laid a solid foundation for expanding applications of Ti-based metallic glasses, especially in heavy-duty and corrosive domains. 相似文献
2.
3.
S N Ojha 《Bulletin of Materials Science》1992,15(6):527-542
Spray forming involves sequential gas atomization of a melt into a spray of fine droplets and their deposition on a substrate
to build up a high-density preform. The rapid solidification inherent in spray deposition generates refined, equiaxed and
low segregation microstructures. A number of promising features of this near-net shape manufacturing process are highlighted
and compared, wherever possible, with the conventional casting and PM techniques. Some commercial nozzles used to create spray
and mechanisms associated with spray generation are described. The consolidation of the droplets and the development of the
microstructure in the deposit are primarily governed by the nature of the spray and the thermal state of droplets on the deposition
surface. Several microstructural characteristics of the deposit are presented and their origin in spray deposition is discussed. 相似文献
4.
雾化水流计算模式 总被引:21,自引:1,他引:20
梁在潮 《水动力学研究与进展(A辑)》1992,7(3):247-255
本文描述了雾化水流现象并提出了雾化水流的一个计算模型。得出了雾化水流影响领域的各种不同的计算公式和方法。 相似文献
5.
6.
In close-coupled gas atomization(CCGA), the influences of melt superheat on breakup process are fundamental to obtain desired or finer powder. Based on a series of Cu atomization experiment under different superheating conditions, the influences of melt superheat on breakup process were studied. Experimental results indicate that as the melt superheat is increased to 150, 200, 250 and 300 K, the mean particle size (D50) decreases consequently to 34.9, 32.3, 30.9 and 19.7 μm. Theoretical analysis reveals that the primary breakup and secondary breakup processes are close coupled, and the melt superheat radically influences the melt properties, and plays a crucial role on governing the filming process of primary breakup and the atomization modes of secondary breakup. There exists a strong nonlinear decrease of contact angle of melt to nozzle orifice wall when the superheat is increased fi'om 250 K to 300 K, leading to a marked fall of the film thickness formed in primary breakup, and D50 of copper powders is therefore sharply reduced. However, the log-normal distribution feature of particle size has not been substantially improved. 相似文献
7.
采用气雾化(IGA)制备了Al-Ni-Co粉末,初筛后的最大粉末粒径小于150μm。分别采用霍尔流速计、XRD、SEM、VSM等测试方法研究了不同粒径范围Al-Ni-Co微粉的微观形貌、相成分、磁性能等。研究表明:微粉的球化率在95%左右;50~80μm范围微粉的流动性相对最好;20μm以下微粉因为粒径偏小,成分偏析较为严重;80~150μm微粉因为粒径过大,表面吸附卫星小颗粒,粗糙度较差;Al-Ni-Co微粉的磁性为软磁,相组成为AlNi和FeCo相。综合比较微观结构、相成分及粉末占比量,选取20~80μm的Al-Ni-Co微粉采用SLM法制备了6组Al-Ni-Co圆柱形磁体,热处理后磁体的密度、磁性等综合性能达到铸造Al-Ni-Co磁体的性能水平。 相似文献
8.
9.
K. A. Khor F. Y. C. Boey Y. Murakoshi T. Sano 《Journal of Thermal Spray Technology》1994,3(2):162-168
There has been increasing use of Al-Li alloys in the aerospace industry, due mainly to the low density and high elastic modulus
of this material. However, the problem of low ductility and fracture toughness of this material has limited its present application
to only weight- and stiffness-critical components. Development of Al-Li/ceramic composites is currently being investigated
to enhance the service capabilities of this material. The Ti-Al alloy is also of interest to aerospace-type applications,
engine components in particular, due to its attractive high-temperature properties. Preparation of fine powders by plasma
melting of composite feedstock and coatings formed by plasma spraying was carried out to examine the effect of spray parameters
on the microstructure and properties of these materials. Characterization of the powders and coatings was performed using
the scanning electron microscope and image analyzer. Examination of the plasma-sprayed powders and coatings has shown that
in the Al-Li/SiC composite there is melting of both materials to form a single composite particle. The SiC reinforcement was
in the submicron range and contributed to additional strengthening of the composite body, which was formed by a cold isostatic
press and consolidated by hot extrusion or hot forging processes. The plasma-sprayed Ti-Al powder showed four categories of
microstructures: featureless, dendritic, cellular, and martensite-like. 相似文献
10.
生物柴油与普通柴油任意比例互溶的混合物可以代替石化柴油供内燃机使用,为了使得这种混合物在内燃机应用中达到好的动力性和排放效果,就需要研究不同比例的生物柴油—柴油混合物的雾化效果。利用数字图像处理的方法对生物柴油-柴油混合物雾化图像进行处理,获得了单位面积内雾化粒度的数量和平均直径,处理速度快捷、准确,减少了传统人工方法分析的主观性和较高的失误率。 相似文献