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31.
及时掌握火驱过程中火线的位置,有助于进行生产调控,通过调研现场预测火线位置的方法,得出一套针对不同特征油藏的适用方法:红外照相法适用于浅层油藏;用测温元件直接测试法适用于观察井和生产井密集的油藏;生产动态和物质平衡相结合的方法适用于均质性好且井网形式规范的油藏;示踪剂监测和生产动态相结合的方法适用于非均质性严重或井网形式不规范的油藏;压降试井法由于计算复杂,有待进一步研究。最后指出应在前期地质筛选的基础上,做到"少注气、多采油",并结合生产动态分析加强对油井的管理,引导燃烧前缘均匀稳定的推进。 相似文献
32.
《Ceramics International》2021,47(18):25846-25853
During the crack propagation in common refractory ceramics at high temperatures, creep may occur in the wake of a process zone and in front of a crack tip. To account for this phenomenon, an integrated material constitutive model was developed by combining the mechanical behavior following isotropic damaged elasticity concept and Norton-Bailey creep. The post peak fracture behavior followed the bilinear softening law and a simple criterion was defined to consider the creep asymmetricity in uniaxial tension and compression. The material constitutive model was applied to inversely identify mode I fracture parameters with wedge splitting tests of an alumina spinel material at 1200 °C. It showed that the mean ratio of the nominal notch tensile strength to the actual tensile strength was 1.93 and the mean pure fracture energy was 297.6 N/m. In addition, the creep contributed 12.9% on average into the total fracture energy. 相似文献
33.
Magnesium alloys are of increasing interest to the automobile industry for their potential in reducing vehicle weight, and in turn, improving fuel economy and lowering emissions. It follows that improving the magnesium manufacturing processes will promote greater use of magnesium alloys in automobiles. In recent years, diamond-like carbon (DLC) coatings have attracted attention for their low coefficient of friction (COF) and wear rates. The implementation of DLC coatings on tool and die surfaces may help increase the efficiency of magnesium component manufacturing processes (such as cutting and sheet forming) and also improve the surface quality of the finished products.In this study, the dry sliding wear behaviour of magnetron sputtered non-hydrogenated DLC coatings against Mg (> 99.9 wt.%) was investigated using a vacuum pin-on-disc tribometer. Tests were performed in ambient air (28% RH) and in argon, under a constant load of 5 N and at a sliding speed of 0.12 m/s. In argon, the non-hydrogenated DLC coatings showed a very low COF of 0.05 after an initial running-in period. Carbonaceous material transfer from the non-hydrogenated DLC to the contact surface of the Mg pin was observed in argon. Changing the test atmosphere from argon to ambient air increased the COF to 0.40, which was accompanied by the formation of oxidized Mg debris and an increased wear rate. The friction and wear mechanisms of non-hydrogenated DLC coatings against Mg are proposed to rationalize experimental observations. 相似文献
34.
High-throughput drilling of titanium alloys 总被引:3,自引:1,他引:3
Rui Li Parag Hegde Albert J. Shih 《International Journal of Machine Tools and Manufacture》2007,47(1):63-74
Experiments of high-throughput drilling of Ti–6Al–4V at 183 m/min cutting speed and 156 mm3/s material removal rate (MRR) using a 4 mm diameter WC–Co spiral point drill were conducted. The tool material and geometry and drilling process parameters, including cutting speed, feed, and fluid supply, were studied to evaluate the effect on drill life, thrust force, torque, energy, and burr formation. The tool wear mechanism, hole surface roughness, and chip light emission and morphology for high-throughput drilling were investigated. Supplying the cutting fluid via through-the-drill holes has proven to be a critical factor for drill life, which can be increased by 10 times compared to that of dry drilling at 183 m/min cutting speed and 0.051 mm/rev feed. Under the same MRR of 156 mm3/s with a doubled feed of 0.102 mm/rev (91 m/min cutting speed), over 200 holes can be drilled. The balance of cutting speed and feed is essential to achieve long drill life and good hole surface roughness. This study demonstrates that, using proper drilling process parameters, spiral point drill geometry, and fine-grained WC–Co tool material, the high-throughput drilling of Ti alloy is technically feasible. 相似文献
35.
Biing-Hwa Yan Hsinn-Jyh Tzeng Fuang Yuan Huang Yan-Cherng Lin Han-Ming Chow 《International Journal of Machine Tools and Manufacture》2007,47(6):920-926
This study presents a spiral polishing method and a device for micro-finishing purposes. This novel finishing process has wider application than traditional processes. This offers both automation and flexibility in final machining operations for deburring, polishing, and removing recast layers, thereby producing compressive residual stresses even in difficult to reach areas. Applying of this method can obtain a fine polished surface by removing tiny fragments via a micro lapping generated by transmission of an abrasive medium through a screw rod. The effect of the removal of the tiny fragments can be achieved due to the function of micro lapping. The method is not dependent on the size of the work-piece's application area in order to carry out the ultra precise process. The application of this research can be extended to various products of precision ball-bearing lead screw. The proposed method produces products with greater precision and more efficiently than traditional processes, in terms of processing precisions and the surface quality of products. These parameters used in achieving maximum material removal rate (MRR) and the lowest surface roughness (SR) are abrasive particle size, abrasive concentration, gap, revolution speed and machining time. 相似文献
36.
37.
减振降噪阻尼材料及其应用 总被引:15,自引:0,他引:15
介绍国内外减振材料的发展概况、着重阐述自行研制的S2复合阻尼钢板的各种性能及在多种结构上的抑振降噪效果,并对S2复合阻尼钢板的抑振降噪机理进行了初步的探讨。实践证明,S2复合阻尼钢板是一种抑振降噪的有效材料。 相似文献
38.
冲模材料选择与热处理要求的分析 总被引:2,自引:0,他引:2
林朝平 《锻压装备与制造技术》2004,39(4):74-75
通过分析冲模材料和热处理对模具寿命的影响,指出了冲模材料的选取原则和相应的模具热处理规范,并介绍了这些关键因素在生产实际中的应用。 相似文献
39.
半固态金属流变成形模具失效与选材 总被引:4,自引:3,他引:4
半固态流变成形模具的研究是半固态成形技术的一个重要组成部分,目前还没有引起足够的重视。根据半固态流变成形模具的工作原理和黑色金属流变成形的工作条件,分析指出了其主要失效形式是热疲劳、熔蚀和变形,模具材料的关键性能指标是高温疲劳强度、抗氧化性以及较低的线膨胀系数等。通过对常用模具材料优缺点的分析,得出了以下结论:目前国内外还没有真正适合黑色金属半固态流变成形的模具材料,采用复合材料和表面处理技术是提高模具寿命的有效途径。 相似文献
40.