全文获取类型
收费全文 | 95387篇 |
免费 | 6685篇 |
国内免费 | 3630篇 |
专业分类
电工技术 | 5287篇 |
技术理论 | 5篇 |
综合类 | 5658篇 |
化学工业 | 15574篇 |
金属工艺 | 5512篇 |
机械仪表 | 6429篇 |
建筑科学 | 6224篇 |
矿业工程 | 2678篇 |
能源动力 | 2248篇 |
轻工业 | 6204篇 |
水利工程 | 1786篇 |
石油天然气 | 5551篇 |
武器工业 | 675篇 |
无线电 | 9994篇 |
一般工业技术 | 13921篇 |
冶金工业 | 5463篇 |
原子能技术 | 1270篇 |
自动化技术 | 11223篇 |
出版年
2024年 | 272篇 |
2023年 | 1278篇 |
2022年 | 2391篇 |
2021年 | 3391篇 |
2020年 | 2732篇 |
2019年 | 2458篇 |
2018年 | 3217篇 |
2017年 | 3569篇 |
2016年 | 3447篇 |
2015年 | 3649篇 |
2014年 | 4963篇 |
2013年 | 5906篇 |
2012年 | 6065篇 |
2011年 | 6588篇 |
2010年 | 5904篇 |
2009年 | 5812篇 |
2008年 | 5634篇 |
2007年 | 5247篇 |
2006年 | 5025篇 |
2005年 | 3974篇 |
2004年 | 2887篇 |
2003年 | 2496篇 |
2002年 | 2626篇 |
2001年 | 2274篇 |
2000年 | 2230篇 |
1999年 | 2239篇 |
1998年 | 1870篇 |
1997年 | 1650篇 |
1996年 | 1227篇 |
1995年 | 990篇 |
1994年 | 795篇 |
1993年 | 577篇 |
1992年 | 512篇 |
1991年 | 335篇 |
1990年 | 272篇 |
1989年 | 202篇 |
1988年 | 152篇 |
1987年 | 99篇 |
1986年 | 88篇 |
1985年 | 79篇 |
1984年 | 59篇 |
1983年 | 51篇 |
1982年 | 42篇 |
1981年 | 33篇 |
1980年 | 39篇 |
1979年 | 34篇 |
1978年 | 30篇 |
1976年 | 31篇 |
1970年 | 18篇 |
1969年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 515 毫秒
51.
Breslavs’kyi D. V. Metel’yov V. O. Morachkovs’kyi O. K. Tatarinova O. A. 《Strength of Materials》2019,51(5):753-760
Strength of Materials - Creep constitutive equations have been derived for the materials that exhibit the properties of orthotropy (transversal isotropy) and transient creep under cyclic loading. A... 相似文献
52.
Kazantsev Yu. N. Kraftmakher G. A. Mal’tsev V. P. 《Journal of Communications Technology and Electronics》2019,64(6):550-554
Journal of Communications Technology and Electronics - Approximate formulas for calculating the coefficient of reflection from an artificial magnetic conductor (AMC) based on a capacitive lattice... 相似文献
53.
Guangbo Zeng Dongqing Zhang Liuming Yan Baohua Yue Ting Pan Yidong Hu Shufa He Hongbin Zhao Jiujun Zhang 《International Journal of Hydrogen Energy》2021,46(39):20664-20677
Side-chain optimized poly (2,6-dimethyl-1,4-phenylene oxide)-g-poly (styrene sulfonic acid) (PPO-g-PSSA) is designed with balanced water-resistance and sulfonation degree. The PPO-g-PSSA is synthesized by controlled atom-transfer radical polymerization (ATRP) from brominated poly (2,6-dimethyl-1,4-phenylene oxide) (PPO-xBr) and ethyl styrene-4-sulfonate and followed by hydrolysis. A series of PPO-g-PSSA are prepared possessing different bromination degree (x) of PPO-xBr and polymerization degree (m) of the side-chains and the water-resistances of the fabricated membranes are investigated. The results show that a PPO-g-PSSA at relatively low x (x < 0.2) and high m (m > 4) exhibits good balance between the water-resistance and the sulfonation degree. Namely, it displays suitable proton conductivity with compromised water-resistance. Moreover, a maximum ion exchange capacity (IEC) of 3.24 mmol g?1 is reached without the sacrifice of water-resistance. In addition, PPO-g-0.08PSSA-13 and PPO-g-0.14PSSA-4 are chosen characterized by thermogravimetric analysis, proton conductivities and mechanical properties. At 90% RH, the optimized PPO-g-0.08PPSA-13 possesses a proton conductivity of 37.9 mS cm?1 at 40 °C and 45.5 mS cm?1 at 95 °C, respectively. 相似文献
54.
Zinov’eva I. V. Fedorov A. Ya. Milevskii N. A. Zakhodyaeva Yu. A. Voshkin A. A. 《Theoretical Foundations of Chemical Engineering》2021,55(4):663-670
Theoretical Foundations of Chemical Engineering - A choline chloride–sulfosalicylic acid deep eutectic solvent (DES) is proposed for dissolving the oxides Co(II), Cu(II), Zn(II), Fe(III),... 相似文献
55.
Chertkov Yu. B. Anikin M. N. Lebedev I. I. Naimushin A. G. Smol’nikov N. V. 《Atomic Energy》2021,131(1):42-45
Atomic Energy - The results of calculations and experimental determination of the neutronics characteristics of the IRT-T research reactor are presented. The IRT-T reactor is a pool reactor with... 相似文献
56.
Baofu Qiu Xiaoming Duan Zhuo Zhang Delong Cai Ning Liao Peigang He Dechang Jia Yu Zhou 《Ceramics International》2021,47(1):73-79
The effects of La2O3–Al2O3–SiO2 addition on the thermal conductivity, coefficient of thermal expansion (CTE), Young's modulus and cyclic thermal shock resistance of hot-pressed h-BN composite ceramics were investigated. The samples were heated to 1000 °C and then quenched to room temperature with 1–50 cycles, and the residual flexural strength was used to evaluate cyclic thermal shock resistance. h-BN composite ceramics containing 10 vol% La2O3–Al2O3 and 20 vol% SiO2 addition exhibited the highest flexural strength, thermal conductivity and relatively low CTE, which were beneficial to the excellent thermal shock resistance. In addition, the viscous amorphous phase of ternary La2O3–Al2O3–SiO2 system could accommodate and relax thermal stress contributing to the high thermal shock resistance. Therefore, the residual flexural strength still maintained the value of 234.3 MPa (86.9% of initial strength) after 50 cycles of thermal shock. 相似文献
57.
Wang Zhicheng Xu Kangwei Ruan Shangshang He Chenliang Zhang Lidong Liu Fuyi 《Catalysis Letters》2022,152(9):2695-2704
Catalysis Letters - A series of mesoporous cobalt–manganese catalysts were successfully synthesized by sol–gel method as efficient catalysts for the propane oxidation. A significant... 相似文献
58.
Zakraoui Jezia Saleh Moutaz Al Ja’am Jihad 《Multimedia Tools and Applications》2019,78(16):22833-22859
Multimedia Tools and Applications - Text-to-picture systems attempt to facilitate high-level, user-friendly communication between humans and computers while promoting understanding of natural... 相似文献
59.
设备综合管理工作始终贯穿在项目建设整个过程中.从项目立项审查、基础设计审查、设备订货前的技术把关,到工程施工环节的专业技术检查,再到项目中交、联动试车、投料试车,处处可见设备综合管理的内容.本文梳理出设备综合管理的主要节点内容、现状和存在的问题,针对镇海基地项目群的建设,就如何发挥设备专业化的优势、如何对设备综合管理工作进行创新、如何优化工作流程进行了探索.旨在通过设备综合管理工作的统筹和协调,将专业化优势形成合力,更高质量、更高效率地为项目建设服务. 相似文献
60.
Byakova O. V. Stepanov G. V. Vlasov A. O. Danylyuk V. E. Semenov N. V. Berezovs’kyi O. M. Gnyloskurenko S. V. 《Strength of Materials》2019,51(5):726-734
Strength of Materials - The paper addresses the investigation of high-strain rate compressive behavior of Al foams subjected to impact at the intermediate striking velocity ranged from 40 to... 相似文献