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81.
82.
主要研究了Al/Zn-3Al/Cu钎焊接头在凝固过程中实施超声处理时其钎缝层显微结构和性能的演变。研究结果表明,在未经凝固超声处理的钎焊接头中,钎缝层呈现出一种各向异性的显微结构;然而,在经过凝固超声处理的钎焊接头中,钎缝层有着均匀的显微结构,其由一种等轴的花瓣状Cu Zn5/Al复合物以及弥散其间的细小α-Al晶粒和Zn-Al共晶组织组成。性能测试结果表明,与未经凝固超声处理的钎焊接头相比,经过凝固超声处理的接头钎缝层的硬度增加了26.2%,热膨胀系数降低了38%。 相似文献
83.
Dong Hyeop Shin Ji Hye Kim Young Min Shin Kyung Hoon Yoon Essam A. Al‐Ammar Byung Tae Ahn 《Progress in Photovoltaics: Research and Applications》2013,21(2):217-225
ZnS is a candidate to replace CdS as the buffer layer in Cu(In,Ga)Se2 (CIGS) solar cells for Cd‐free commercial product. However, the resistance of ZnS is too large, and the photoconductivity is too small. Therefore, the thickness of the ZnS should be as thin as possible. However, a CIGS solar cell with a very thin ZnS buffer layer is vulnerable to the sputtering power of the ZnO : Al window layer deposition because of plasma damage. To improve the efficiency of CIGS solar cells with a chemical‐bath‐deposited ZnS buffer layer, the effect of the plasma damage by the sputter deposition of the ZnO : Al window layer should be understood. We have found that the efficiency of a CIGS solar cell consistently decreases with an increase in the sputtering power for the ZnO : Al window layer deposition onto the ZnS buffer layer because of plasma damage. To protect the ZnS/CIGS interface, a bilayer ZnO : Al film was developed. It consists of a 50‐nm‐thick ZnO : Al plasma protection layer deposited at a sputtering power of 50 W and a 100‐nm‐thick ZnO : Al conducting layer deposited at a sputtering power of 200 W. The introduction of a 50‐nm‐thick ZnO : Al layer deposited at 50 W prevented plasma damage by sputtering, resulting in a high open‐circuit voltage, a large fill factor, and shunt resistance. The ZnS/CIGS solar cell with the bilayer ZnO : Al film yielded a cell efficiency of 14.68%. Therefore, the application of bilayer ZnO : Al film to the window layer is suitable for CIGS solar cells with a ZnS buffer layer. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
84.
为研究基体合金对B4C/Al复合材料力学性能及抗弹性能的影响,选择强度、硬度和塑性各不相同的5083Al、2024Al和7075Al铝合金为基体合金,采用压力浸渗工艺制备B4C颗粒增强体积分数为55%的B4C/5083Al、B4C/2024Al和B4C/7075Al复合材料,并对其进行力学性能和抗弹性能测试。结果表明:3种B4C/Al复合材料的力学性能特征与基体铝合金相对应,B4C/7075Al复合材料的强度和硬度最高,抗侵彻能力最好,侵彻深度为15.7 mm,防护系数为4.13;B4C/5083Al复合材料的塑性最好,其靶板整体能力最好。 相似文献
85.
Yaxi Ding Siwen Zhang Jiazhuo Li Ying Sun Bosi Yin Hui Li Yue Ma Zhiqiao Wang Hao Ge Dawei Su Tianyi Ma 《Advanced functional materials》2023,33(2):2210519
The harsh conditions of large hydrated ion radius of Mg2+ cations and the strong electrostatic interaction with the host material put forward higher requirements for high-performance aqueous magnesium ion (Mg2+) energy storage devices. Herein, substituted aluminium ions (Al3+) doped α-MnO2 materials are prepared. The introduction of Al3+ cations adjust the local chemical environment inside the tunnel structure of α-MnO2 and precisely regulates the diffusion behavior of inserted Mg2+ cations. The shortened oxygens’ distance and abundant oxygen defects result in a substantially enhanced elastic migration pattern of Mg2+ cations driven by strengthened electrostatic attraction, which brings the lower diffusion energy barrier, improved reaction kinetics, and adaptive volume expansion as evidenced by Climbing Image-Nudged Elastic Band density function theory calculations coupled with experimental confirmation in X-ray photoelectron spectroscopy, electron paramagnetic resonance, and galvanostatic intermittent titration technique. As a result, this rationally designed cathode exhibits a high reversible capacity of 197.02 mAh g-1 at 0.1 A g-1 and stable cycle performance of 2500 cycles with 82% retention. These parameters are among the best of Mg-ion capacitors reported to date. This study offers a detailed insight into the local tunnel structure tunning effect and opens up a new path of modification for tunnel-type structural materials. 相似文献
86.
In this study, we report the structural modification and change in electrical behaviour of aluminium doped zinc oxide by low energy (100 keV) proton irradiation. Aluminium doped zinc oxide films were deposited using DC magnetron sputtering and then annealed for a short duration at 600 °C before irradiation. Structural and defect studies of the films carried out using XRD and Raman spectroscopy. It suggests that the crystalline ordering increases at higher fluences due to annealing of defects in the film. The increase in crystallinity at higher fluences decreases the grain boundary scattering and causes low resistivity. There is no significant change in carrier concentration after the irradiation, however the mobility and resistivity of the Al doped ZnO films change with proton irradiated fluences. The development of defect due to irradiation has been confirmed through Raman spectroscopic studies. The increase in activation energy of particles has been suggested by low energy proton irradiations at higher fluences in the annealed Al doped ZnO thin films. The uniform particle distribution increases with fluences of the irradiation that may be helpful for spintronics and sensor device technology. 相似文献
87.
Nonvolatile rewritable organic memory devices based on poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and nitrogen doped multi-walled carbon nanotube (NCNT) nanocomposites were fabricated on glass and PET substrates.Organic memory devices with bistable resistive switching were obtained using very low NCTN concentration (∼0.002 wt%) in the polymeric matrix. The memory devices exhibited a good ON/OFF ratio of approximately three orders of magnitude, a good retention time of 104 s under operating voltages ≤ |4V| and a few hundredths of write-read-erase-read cycles. The bistable resistive switching is mainly attributed to the creation of oxygen vacancies. These defects are introduced into the thin native Al oxide (AlOx) layer on the bottom electrode during the first voltage sweep. The well-dispersed NCNTs immersed in PEDOT:PSS play a key role as conductive channels for the electronic transport, hindering the electron trapping at the AlOx-polymer interface and inducing a soft dielectric breakdown of the AlOx layer. These PEDOT:PSS + NCNTs memory devices are to easy to apply in flexible low-cost technology and provide the possibility of large-scale integration. 相似文献
88.
89.
在对冲压焊接铝合金车毂进行结构强度有限元分析的基础上 ,对Al-Zn -Mg系合金的热处理工艺及焊后性能进行了相关试验。试验结果表明 ,上述合金能满足冲压焊接铝合金车毂的使用要求。 相似文献
90.
Al2O3基陶瓷抗弹性能的研究 总被引:1,自引:0,他引:1
以添加ZrO2的Al2O3基陶瓷材料为研究对象,经过成分优化设计以及成型、烧结工艺优化设计,制备出性能高且稳定的材料;并采用模拟穿甲弹和破甲弹对装甲钢、几种陶瓷材料进行了对比试验,测定了防护系数;并分析了几种材料抗穿、破甲弹防护系数不同的原因。 相似文献