全文获取类型
收费全文 | 262039篇 |
免费 | 20340篇 |
国内免费 | 13345篇 |
专业分类
电工技术 | 16818篇 |
技术理论 | 51篇 |
综合类 | 36312篇 |
化学工业 | 28526篇 |
金属工艺 | 9774篇 |
机械仪表 | 14142篇 |
建筑科学 | 37471篇 |
矿业工程 | 14889篇 |
能源动力 | 7957篇 |
轻工业 | 14601篇 |
水利工程 | 13933篇 |
石油天然气 | 11134篇 |
武器工业 | 2513篇 |
无线电 | 17123篇 |
一般工业技术 | 18477篇 |
冶金工业 | 15437篇 |
原子能技术 | 2671篇 |
自动化技术 | 33895篇 |
出版年
2024年 | 814篇 |
2023年 | 2489篇 |
2022年 | 4815篇 |
2021年 | 5788篇 |
2020年 | 6141篇 |
2019年 | 5137篇 |
2018年 | 4856篇 |
2017年 | 5925篇 |
2016年 | 7021篇 |
2015年 | 7870篇 |
2014年 | 14535篇 |
2013年 | 13195篇 |
2012年 | 17256篇 |
2011年 | 18361篇 |
2010年 | 14625篇 |
2009年 | 15272篇 |
2008年 | 14271篇 |
2007年 | 18756篇 |
2006年 | 17829篇 |
2005年 | 15597篇 |
2004年 | 13297篇 |
2003年 | 11993篇 |
2002年 | 9896篇 |
2001年 | 8368篇 |
2000年 | 7056篇 |
1999年 | 5760篇 |
1998年 | 4361篇 |
1997年 | 3825篇 |
1996年 | 3547篇 |
1995年 | 2997篇 |
1994年 | 2679篇 |
1993年 | 2007篇 |
1992年 | 1782篇 |
1991年 | 1328篇 |
1990年 | 1157篇 |
1989年 | 1026篇 |
1988年 | 823篇 |
1987年 | 564篇 |
1986年 | 426篇 |
1985年 | 353篇 |
1984年 | 330篇 |
1983年 | 240篇 |
1982年 | 214篇 |
1981年 | 165篇 |
1980年 | 130篇 |
1979年 | 110篇 |
1978年 | 62篇 |
1977年 | 72篇 |
1976年 | 55篇 |
1975年 | 55篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Jean-Claude Malela-Majika Sandile Charles Shongwe Olatunde Adebayo Adeoti 《Quality and Reliability Engineering International》2021,37(8):3314-3322
The sensitivity of a monitoring scheme depends on many factors including the variance of the charting statistic which is very important in the computation of the control limits. This paper discusses the computation of the variance of the recently proposed hybrid homogeneously weighted moving average (HHWMA) scheme which was based on an incorrect assumption. The correct variance is used to evaluate the run-length characteristics of the HHWMA scheme. It is observed that the incorrect variance has a significant impact on the sensitivity (or performance) of the HHWMA scheme. 相似文献
2.
3.
本文以云杉八齿小蠹Ips typographus Linnaeus为例,经标本选取,观察虫体整体形态,绘制整体结构草图,电子显微镜观察局部、得到局部数字图像,分别建立虫体每一部分的高精度细节。把模型每部分拼装在一起组成整体模型,构建出了云杉八齿小蠹三维虚拟昆虫数字化模型。 相似文献
4.
5.
6.
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
8.
9.
10.
The 2011 AASHTO Roadside Design Guide (RDG) contains perhaps the most widely used procedure for choosing an appropriate length of need (LON) for roadside barriers. However, this procedure has several limitations. The procedure uses a highly simplified model of vehicle departure, and the procedure does not allow designers to specify an explicit level of protection. A new procedure for choosing LON that addresses these limitations is presented in this paper. This new procedure is based on recent, real-world road departure trajectories and uses this departure data in a more realistic way. The new procedure also allows LON to be specified for a precisely known level of protection – a level which can be based on number of crashes, injury outcomes or even estimated crash cost – while still remaining straightforward and quick to use like the 2011 RDG procedure. 相似文献