全文获取类型
收费全文 | 293392篇 |
免费 | 22229篇 |
国内免费 | 14423篇 |
学科分类
工业技术 | 330044篇 |
出版年
2024年 | 882篇 |
2023年 | 2791篇 |
2022年 | 5388篇 |
2021年 | 6453篇 |
2020年 | 6781篇 |
2019年 | 5667篇 |
2018年 | 5355篇 |
2017年 | 6548篇 |
2016年 | 7709篇 |
2015年 | 8836篇 |
2014年 | 16228篇 |
2013年 | 14823篇 |
2012年 | 18959篇 |
2011年 | 20750篇 |
2010年 | 16405篇 |
2009年 | 17234篇 |
2008年 | 16285篇 |
2007年 | 21267篇 |
2006年 | 20119篇 |
2005年 | 17631篇 |
2004年 | 14994篇 |
2003年 | 13513篇 |
2002年 | 11103篇 |
2001年 | 9232篇 |
2000年 | 7775篇 |
1999年 | 6342篇 |
1998年 | 4789篇 |
1997年 | 4148篇 |
1996年 | 3839篇 |
1995年 | 3210篇 |
1994年 | 2855篇 |
1993年 | 2142篇 |
1992年 | 1891篇 |
1991年 | 1425篇 |
1990年 | 1228篇 |
1989年 | 1084篇 |
1988年 | 879篇 |
1987年 | 590篇 |
1986年 | 445篇 |
1985年 | 380篇 |
1984年 | 355篇 |
1983年 | 258篇 |
1982年 | 228篇 |
1981年 | 175篇 |
1980年 | 137篇 |
1979年 | 122篇 |
1978年 | 73篇 |
1977年 | 81篇 |
1976年 | 66篇 |
1975年 | 59篇 |
排序方式: 共有10000条查询结果,搜索用时 21 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.
Value stream mapping (VSM) is a useful tool for describing the manufacturing state, especially for distinguishing between those activities that add value and those that do not. It can help in eliminating non-value activities and reducing the work in process (WIP) and thereby increase the service level. This research follows the guidelines for designing future state VSM. These guidelines consist of five factors which can be changed simply, without any investment. These five factors are (1) production unit; (2) pacemaker process; (3) number of batches; (4) production sequence; and (5) supermarket size. The five factors are applied to a fishing net manufacturing system. Using experimental design and a simulation optimizing tool, the five factors are optimized. The results show that the future state maps can increase service level and reduce WIP by at least 29.41% and 33.92% respectively. For the present study, the lean principles are innovatively adopted in solving a fishing net manufacturing system which is not a well-addressed problem in literature. In light of the promising empirical results, the proposed methodologies are also readily applicable to similar industries. 相似文献
5.
6.
7.
8.
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
9.
We introduce a new architecture for the design of a tool for modeling and simulation of continuous and hybrid systems. The environment includes a compiler based on Modelica, a modular and a causal standard specification language for physical systems modeling (the tool supports models composed using certain component classes defined in the Modelica Standard Library, and the instantiation, parameterization and connection of these MSL components are described using a subset of Modelica). Models are defined in Modelica and are translated into DEVS models. DEVS theory (originally defined for modeling and simulation of discrete event systems) was extended in order to permit defining these of models. The different steps in the compiling process are show, including how to model these dynamic systems under the discrete event abstraction, including examples of model simulation with their execution results. 相似文献