全文获取类型
收费全文 | 317883篇 |
免费 | 27069篇 |
国内免费 | 17748篇 |
专业分类
电工技术 | 23854篇 |
技术理论 | 51篇 |
综合类 | 42346篇 |
化学工业 | 37893篇 |
金属工艺 | 12168篇 |
机械仪表 | 17129篇 |
建筑科学 | 44041篇 |
矿业工程 | 17150篇 |
能源动力 | 10320篇 |
轻工业 | 19416篇 |
水利工程 | 16903篇 |
石油天然气 | 13542篇 |
武器工业 | 3107篇 |
无线电 | 20195篇 |
一般工业技术 | 23512篇 |
冶金工业 | 16670篇 |
原子能技术 | 3414篇 |
自动化技术 | 40989篇 |
出版年
2024年 | 978篇 |
2023年 | 3340篇 |
2022年 | 6310篇 |
2021年 | 7598篇 |
2020年 | 8046篇 |
2019年 | 6976篇 |
2018年 | 6497篇 |
2017年 | 7812篇 |
2016年 | 9105篇 |
2015年 | 10165篇 |
2014年 | 17694篇 |
2013年 | 16896篇 |
2012年 | 21302篇 |
2011年 | 22728篇 |
2010年 | 17870篇 |
2009年 | 18790篇 |
2008年 | 17565篇 |
2007年 | 22583篇 |
2006年 | 21196篇 |
2005年 | 18459篇 |
2004年 | 15734篇 |
2003年 | 13953篇 |
2002年 | 11552篇 |
2001年 | 9788篇 |
2000年 | 8368篇 |
1999年 | 6944篇 |
1998年 | 5284篇 |
1997年 | 4660篇 |
1996年 | 4264篇 |
1995年 | 3609篇 |
1994年 | 3217篇 |
1993年 | 2427篇 |
1992年 | 2158篇 |
1991年 | 1609篇 |
1990年 | 1372篇 |
1989年 | 1184篇 |
1988年 | 940篇 |
1987年 | 646篇 |
1986年 | 475篇 |
1985年 | 399篇 |
1984年 | 392篇 |
1983年 | 280篇 |
1982年 | 260篇 |
1981年 | 183篇 |
1980年 | 161篇 |
1979年 | 131篇 |
1978年 | 72篇 |
1977年 | 78篇 |
1976年 | 59篇 |
1975年 | 59篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
有机化学是化学化工、材料、制药、食品等多个专业的基础课程,在其教学过程中,教师可以根据课程的内容及特点,分别以有机化学发展中的重大历史事件、有机化物的性质及有机反应为引导,开展学生的思想品德教育,加强课程思政建设。 相似文献
62.
63.
冯鹏一 《信息通信技术与政策》2020,(1):12-15
以电信用户入网协议为切入点,电信用户的携号转网行为应受到《合同法》《消费者权益保护法》等私法规范的保护与限制。该行为引起的格式条款解释、合同终止、违约责任、损失赔偿等问题,不能仅靠《电信条例》等公法规范来调整。应当积极引导广大消费者用户以私法领域相关规定为依据,转变争议解决思维,拓宽纠纷处理途径,合理选择维权手段,以保护自身合法民事权益,与行业监管部门共同推动电信行业有序发展。 相似文献
64.
65.
66.
《Journal of the European Ceramic Society》2020,40(15):5475-5482
The lead-free Ba0.53Sr0.47TiO3 (BST) thin films buffered with La0.67Sr0.33MnO3 (LSMO) bottom electrode of different thicknesses were fabricated by pulsed laser deposition method on a (001) SrTiO3 substrate. It was found that the roughness of electrode decreases and substrate stress relaxes gradually with the increase of LSMO thickness, which is beneficial for weakening local high electric field and achieving higher Eb. Therefore, the recoverable energy density (Wrec) of BST films can be greatly improved up to 67.3 %, that is, from 30.6 J/cm3 for the LSMO thickness of 30 nm up to 51.2 J/cm3 for the LSMO thickness of 140 nm after optimizing the LSMO thickness. Furthermore, the thin film capacitor with a 140 nm LSMO bottom electrode shows an outstanding thermal stability from 20 °C to 160 °C and superior fatigue resistance after 108 electrical cycles with only a slightly decrease of Wrec below 1.6 % and 3.7 %, respectively. Our work demonstrates that optimizing bottom electrodes thickness is a promising way for enhancing energy storage properties of thin-film capacitors. 相似文献
67.
68.
A small handful of recent studies have addressed a phenomenon known as “phantom vibration syndrome”. This refers to when phone users perceive their device to vibrate, indicating that a call or text is incoming, when in fact the phone did not vibrate at all. Though these studies show that most users do not find phantom vibration hallucinations to be very bothersome, they also find that a large majority of users experience this phenomenon. This paper explores what the striking prevalence of phantom vibration syndrome means for our contemporary relationships with technology. I begin with a review of the theories purporting to explain these data, which largely rely on particular understandings of the brain. Next I develop an alternative theory of phantom vibration syndrome based on insights from the philosophical tradition of phenomenology. This account considers the ways users develop bodily and perceptual habits regarding how the phone is understood and used. By critically contrasting these different theories, we can refine our questions about what the high prevalence of phantom vibration syndrome implies about our contemporary technological situation. 相似文献
69.
70.
Nazir Kizzie‐Hayford Doris Jaros Yvonne Schneider Harald Rohm 《International Journal of Food Science & Technology》2015,50(2):381-388
A standard method for the extraction of tiger nut milk has been introduced. It has been shown that, although milling duration improves the yield of tiger nut milk solids and its nutrient composition, there is a quantifiable loss of nutrient in the pressing residue during milk extraction. Milling duration improved the colloidal stability of the milk against creaming during 16 h of storage. A higher milling intensity resulted in the aggregation of biological polymers which resulted in colloidal destabilisation. Milling improved the lightness and stability and reduced browning rate of the tiger nut milk during storage. This report is important for the production of tiger nut milk of consistent and comparable characteristics. Milling has been introduced as a processing method for the qualitative and quantitative modulation of the properties of tiger nut milk. It is recommended to develop further strategies to improve the colloidal stability of tiger nut milk as a beverage. 相似文献