全文获取类型
收费全文 | 1520889篇 |
免费 | 26125篇 |
国内免费 | 6999篇 |
专业分类
电工技术 | 34490篇 |
综合类 | 6385篇 |
化学工业 | 272164篇 |
金属工艺 | 64751篇 |
机械仪表 | 43353篇 |
建筑科学 | 46114篇 |
矿业工程 | 11497篇 |
能源动力 | 50379篇 |
轻工业 | 111850篇 |
水利工程 | 15490篇 |
石油天然气 | 37875篇 |
武器工业 | 132篇 |
无线电 | 197556篇 |
一般工业技术 | 287022篇 |
冶金工业 | 170842篇 |
原子能技术 | 34190篇 |
自动化技术 | 169923篇 |
出版年
2021年 | 15604篇 |
2020年 | 11891篇 |
2019年 | 14667篇 |
2018年 | 16915篇 |
2017年 | 16392篇 |
2016年 | 21877篇 |
2015年 | 17463篇 |
2014年 | 28736篇 |
2013年 | 87913篇 |
2012年 | 35898篇 |
2011年 | 49056篇 |
2010年 | 43407篇 |
2009年 | 51753篇 |
2008年 | 45359篇 |
2007年 | 42765篇 |
2006年 | 44604篇 |
2005年 | 39772篇 |
2004年 | 41722篇 |
2003年 | 41653篇 |
2002年 | 40487篇 |
2001年 | 37416篇 |
2000年 | 35830篇 |
1999年 | 35167篇 |
1998年 | 48056篇 |
1997年 | 40750篇 |
1996年 | 36251篇 |
1995年 | 31171篇 |
1994年 | 29157篇 |
1993年 | 29083篇 |
1992年 | 26156篇 |
1991年 | 23270篇 |
1990年 | 23645篇 |
1989年 | 22698篇 |
1988年 | 21208篇 |
1987年 | 19478篇 |
1986年 | 18836篇 |
1985年 | 22154篇 |
1984年 | 22329篇 |
1983年 | 20242篇 |
1982年 | 19235篇 |
1981年 | 19376篇 |
1980年 | 17948篇 |
1979年 | 18442篇 |
1978年 | 17704篇 |
1977年 | 17465篇 |
1976年 | 18382篇 |
1975年 | 15974篇 |
1974年 | 15464篇 |
1973年 | 15573篇 |
1972年 | 12990篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
161.
162.
163.
164.
Semiconductors - We found bulk n-GaAs layers grown by liquid phase epitaxy to be irregularly stressed. Deformation created by this stress causes a small but detectable quadrupole splitting of... 相似文献
165.
Measurement Techniques - An algorithm and program for calculation in ultra-rapid regime of the ephemeris and time information of GLONASS and GPS navigation space vehicles are developed. The results... 相似文献
166.
Metallurgist - We consider domestic and foreign standards for rolled metals used in bridge building. Domestic standards contain elevated requirements to the reliability of rolled metals in terms of... 相似文献
167.
Bakhale Mugdha Hemalatha V. Dhanalakshmi Samiappan Kumar R. Siddharth Jain M. 《Wireless Personal Communications》2020,110(2):573-592
Wireless Personal Communications - A relatively new area of research and development is Swarm Robotics. It is a part of the swarm intelligence field. In the proposed paper, we shall use swarm... 相似文献
168.
Giorgio Benedek Joseph R. Manson Salvador Miret-Artés 《Advanced materials (Deerfield Beach, Fla.)》2020,32(25):2002072
Atom scattering is becoming recognized as a sensitive probe of the electron–phonon interaction parameter λ at metal and metal-overlayer surfaces. Here, the theory is developed, linking λ to the thermal attenuation of atom scattering spectra (in particular, the Debye–Waller factor), to conducting materials of different dimensions, from quasi-1D systems such as W(110):H(1 × 1) and Bi(114), to quasi-2D layered chalcogenides, and high-dimensional surfaces such as quasicrystalline 2ML-Ba(0001)/Cu(001) and d-AlNiCo(00001). Values of λ obtained using He atoms compare favorably with known values for the bulk materials. The corresponding analysis indicates in addition, the number of layers contributing to the electron–phonon interaction, which is measured in an atom surface collision. 相似文献
169.
Kolmachikhina E. B. Sviridov A.V. Naumov K. D. 《Russian Journal of Non-Ferrous Metals》2020,61(5):488-493
Russian Journal of Non-Ferrous Metals - This article is devoted to the influence of sodium lignosulfonate (SL), anionic surfactants (sodium dodecylsulfate (SDS), sodium dodecylbenzene sulfonate... 相似文献
170.
Ming-Puu Chen Asta Y. Z. Lord Yu-Yao Cheng Ku-Chou Tai Wen-Harn Pan 《Journal of Computer Assisted Learning》2020,36(3):383-396
Reflective judgement is crucial for medical-related practitioners in dealing with controversial issues. However, the conformity phenomenon is likely to occur and interfere with reflective judgement learning during interactive activities. Effective strategies are required to moderate the conformity behaviour tendency (CBT) and improve reflective judgement performance (RJP). This study demonstrates two significant results: (a) Compared with the guided self-reflection learning strategy, the online collective reflection (OCR) learning strategy effectively weakened the learners' general CBT while dealing with professional controversial issues; and (b) a significantly negative correlation between the RJP achieved and the change of CBT in online environment was detected in the OCR group. The implications and potential applications in higher education were discussed. Further studies are needed to confirm the long-term effects and the extending application to other professional studies. 相似文献