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141.
The objective of this study is to experimentally investigate the cutting mechanisms of polycrystalline diamond compacts (PDC) using two different lasers: (a) a near infrared Nd:YAG laser (Neodymium-doped Yttrium Aluminum Garnet) of 1064 nm wavelength and 100 μs pulse width; and (b) a green light KTP (Potassium Titanyl Phosphate)/Nd:YAG laser of 532 nm wavelength and 120 ns pulse width. To realize the objective, the study applies polishing, lapping and etching processes to the cut-surfaces of the PDC samples. It further observes and analyzes the processed cut-surfaces with scanning electron microscopy (SEM) and Raman spectroscopy. A discussion is provided to reveal the underlying physics of the laser cutting mechanisms, and a conclusion is drawn based on the outcomes from the experimental investigation and the discussion. 相似文献
142.
Anselmo Eduardo Diniz Adilson Jos de Oliveira 《International Journal of Machine Tools and Manufacture》2004,44(10):1061-1067
The main objective of using cutting fluids in machining operations is the reduction of temperature in the cutting region to increase tool life. However, the advantages offered by cutting fluids have been strongly debated because of their negative effects on the economic aspect, the environment and the health of workers using them. A trend to solve these problems is cutting without fluid, a method named dry cutting, which has been made possible due to technological innovations. This work aims to seek conditions in which dry cutting is satisfactory compared with the flood of fluid (called here wet cutting) usually used. Aiming at this goal, several experiments were carried out varying parameters such as cutting speed, feed, depth of cut and tool material in rough turning of ABNT 1045 steel in dry and wet cutting. The analysis of the results showed that wet turning is, as expected, better for tool life. The second conclusion is that dry cutting cannot be used with large depth of cut. But the main conclusion is that, if the tool material is changed to a more wear resistant one, dry cutting can be used with results very similar to those obtained with a flood of fluid. 相似文献
143.
Surface hardening of Ti-6Al-4V alloy was achieved by carburization in a molten salt bath containing BaCO3 as the carbon-yielding agent with electrolysis within the temperature range 790–930°C. The hardness of the total carburizing layer (TCD) is influenced by the bath temperature, the applied current density and the carburizing period. The major hardening effect is considered to be the formation of a solid solution of carbon in -Ti. The oxide film wrapping at the outermost surface of cathodically charged specimens, identified to be mainly BaTiO3, was formed irrespective of the bath temperature during the quenching process and has no effect on the surface hardening. The optimal carburizing parameters obtained in this study for surface hardening are carburizing at 930±10°C (bath temperature) and 0.3 A/Cm2 (applied current density) for 90 min (carburizing period), while those for tribological properties improvement are carburizing at 860±5°C and 0.3 A/Cm2 for 90 min. 相似文献
144.
B.D. Beake J.F. Smith G.S. Fox-Rabinovich J.L. Endrino 《Surface & coatings technology》2007,201(8):4585-4593
A novel laboratory technique, nano-impact testing, has been used to test Ti1−xAlxN (x = 0.5 and 0.67) PVD coated WC-Co inserts at 25-500 °C. Cutting tool life was studied under conditions of face milling of the structural AISI 1040 steel; the end milling of hardened 4340 steel (HRC 40) and TiAl6V4 alloy. A correlation was found between the results of the rapid nano-impact test and milling tests. When x = 0.67 improved resistance to fracture was found during milling operations and also in the nano-impact test of this coating compared to when x = 0.50. The coating protects the cutting tool surface against the chipping that is typical for cutting operations with intensive adhesive interaction with workpiece materials such as machining of Ti-based alloys. The results give encouragement that the elevated temperature nano-impact test can be used to predict the wear and fracture resistance of hard coatings during milling operations. At 500 °C nanoindentation shows there is a lower H/Er ratio for the PVD coatings compared to room temperature, consistent with reduced fracture observed at this temperature in the nano-impact test. 相似文献
145.
146.
This article shows the quantitative evaluation of the residual grit on a blasted substrate, and the removability of the residual
grit is examined. Carbon steel plates were blasted by white alumina grit with mean diameters of 338 to 1106 μm. The velocity
and the number of grit particles were measured during blasting. The residual grit was removed from a substrate surface by
the dissolution of the blasted substrate surface. A mixed acid solution was used as the dissolution solution. The residual
grit weight was 7 to 17 g/m2. The amount of the residual grit and the penetration depth of the embedded grit increased with increasing grit size. The
penetration depth was 5 to 9% of the mean diameter of the grit. The residual grit weight and the penetration depth increased
with the increase of the momentum of the grit particle.
This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials
Park, OH, 2006. 相似文献
147.
A integrated intelligent system for seam tracking and penetration control is given. The system received information of welding seam error and penetration depth from only one sensor, then, it realized seam tracking and penetration control simultaneously. This paper introduces constitution of the system, methods of information recognition, design of the neuralfuzzy controller and results practically. 相似文献
148.
零件通过渗碳淬火工艺获得的有效硬化层深度,受到许多因素的影响。本文阐述和计算零件的材料成分、奥氏体晶粒度、零件质量效果、淬火冷却烈度、各合金元素的淬透性特性值、碳热、淬火加热温度等的影响,并根据计算值同实验值的比较进行适当的修正,制定出合理的渗碳淬火工艺。 相似文献
149.
螺纹加工自动退刀装置 总被引:1,自引:0,他引:1
为了解决高速车削螺纹时车刀退刀困难的一系列问题 ,经过技术论证 ,设计了螺纹自动退刀装置。本文详细介绍了该装置的设计参数 ,结构要点及制造要求。该装置不仅可用于车削螺纹 ,还可用于台阶轴的加工 相似文献
150.
In this paper, a force model for self-propelled rotary tool is presented. Conventional oblique cutting force predictions were reviewed and extended to predict the cutting forces generated during machining with the self-propelled rotary tools. The model presented is based on Oxley's analysis and was verified by cutting tests using a typical self-propelled tool. Good agreement was obtained between the predicted and the experimentally measured forces under a wide range of cutting conditions. The effect of different cutting conditions on the friction coefficient along the chip/tool interface and tool rake face normal force were also presented and discussed. 相似文献