首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   466篇
  免费   26篇
  国内免费   1篇
电工技术   11篇
综合类   1篇
化学工业   92篇
金属工艺   17篇
机械仪表   13篇
建筑科学   19篇
能源动力   25篇
轻工业   52篇
水利工程   5篇
石油天然气   1篇
无线电   34篇
一般工业技术   71篇
冶金工业   19篇
原子能技术   4篇
自动化技术   129篇
  2023年   3篇
  2022年   10篇
  2021年   35篇
  2020年   14篇
  2019年   19篇
  2018年   16篇
  2017年   18篇
  2016年   12篇
  2015年   13篇
  2014年   18篇
  2013年   49篇
  2012年   32篇
  2011年   32篇
  2010年   29篇
  2009年   27篇
  2008年   16篇
  2007年   23篇
  2006年   24篇
  2005年   18篇
  2004年   12篇
  2003年   11篇
  2002年   7篇
  2001年   9篇
  2000年   3篇
  1999年   4篇
  1998年   6篇
  1997年   3篇
  1996年   5篇
  1995年   5篇
  1994年   4篇
  1993年   1篇
  1992年   3篇
  1990年   1篇
  1988年   2篇
  1985年   3篇
  1983年   1篇
  1981年   2篇
  1979年   1篇
  1977年   1篇
  1974年   1篇
排序方式: 共有493条查询结果,搜索用时 481 毫秒
81.
The present paper proposes a modified version of the Manufacturing cost deployment (MCD) method to analyse engineer-to-order (ETO) production systems. The novel approach, named Project cost deployment (PCD), introduces two substantial and innovative modifications. To begin with, the concept of manual assembly macro-activity replaces the traditional concept of station. Then, a brand-new structure for classifying and analysing losses is introduced, that is specifically defined to deal with the inefficiencies of the manual assembly tasks. The validity of the approach is proved by a real-world industrial application. The obtained results demonstrate that the PCD method allows the analyst to identify the hidden losses and to quantify the wastes from an economical point of view. In addition, PCD permits to estimate the impacts of potential (lean) improvement activities and projects in terms of both efficiency and effectiveness.  相似文献   
82.
Simulation of the fatigue crack propagation in a Wendelstein 7‐X baffle module is performed in this study using both a finite element method‐based software and the UniGrow nonlinear model for small‐scale yielding (SSY) conditions. Some experimental fatigue tests of several cracked baffle modules have been performed through a servo‐hydraulic machine. One of these experimental tests has been considered to simulate fatigue crack propagation in the baffle module. Before starting the experimental test, a first crack partly contained in the welding seam and partly in the steel pipe is found. Subsequently, owing to the applied load, the crack propagated both into the welding seam and into the steel pipe until the plastic zone in the near field attains SSY conditions. Finally, owing to the increase in the extension of the plastic zone, SSY conditions are not more valid, and the breakage of the steel pipe is produced by plastic collapse.  相似文献   
83.
84.
Journal of Materials Science - One of the big challenges for realizing future nuclear fusion reactors is the development of materials able to withstand the high thermal loads and particle fluxes...  相似文献   
85.
This paper presents an overview of test and reliability approaches for approximate computing architectures. We focus on how specific methods for test and reliability can be used to improve the characteristics of approximate computing in terms of power consumption, area, life expectancy and precision. This paper does not address specification and design of approximate hardware/software/algorithms, but provides an in-depth knowledge on how the reliability and test related techniques can be efficiently used to maximize the benefits of approximate computing.  相似文献   
86.
The side panels of the Franciscan Triptych (St. Jerome, St. John the Baptist, and the Archangel Gabriel and St. Francis, St. Onofrio, and the Virgin Annunciate, by Fra Angelico, before 1429) were scanned by means of terahertz time-domain imaging (THz-TDI). THz analysis supplied information on the stratigraphy of the panel paintings and the associated construction, “gessoing” and gilding techniques. Furthermore, THz-TDI provided information regarding the location of restoration materials within the painting stratigraphy on St. Jerome, St. John the Baptist, and the Archangel Gabriel, as well as on the extension and nature of subsurface cracks in the panel painting of St. Francis, St. Onofrio, and the Virgin Annunciate.  相似文献   
87.
In this paper, an analytical model for the electrothermal solution to the non‐linear 3‐D heat flow equation for multilayer structure electronic devices is proposed. Compared with previous models presented in literature, it is general and can be easily applied to a large variety of integrated devices, provided that their structure can be represented as an arbitrary number of superimposed layers with a 2‐D embedded thermal source, so as to include the effect of the package. The proposed method is independent of the specific physical properties of the layers, hence GaAs MESFETs and HEMTs as well as silicon and silicon‐on‐insulator MOSFETs and heterostructure LASERs can be analysed. Moreover, it takes into account the dependence of the thermal conductivity of all the layers on the temperature; the heat equation is solved coupled with the device current–voltage relation in order to give physical consistence to the experimental evidence that a temperature increase causes a degradation of the electrical performances and that the electrical power is not uniformly distributed. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
88.
Epidemiological data have demonstrated a significant association between the presence of type 2 diabetes mellitus (T2DM) and the development of colorectal cancer (CRC). Chronic hyperglycemia, insulin resistance, oxidative stress, and inflammation, the processes inherent to T2DM, also play active roles in the onset and progression of CRC. Recently, small dense low-density lipoprotein (LDL) particles, a typical characteristic of diabetic dyslipidemia, emerged as another possible underlying link between T2DM and CRC. Growing evidence suggests that antidiabetic medications may have beneficial effects in CRC prevention. According to findings from a limited number of preclinical and clinical studies, glucagon-like peptide-1 receptor agonists (GLP-1RAs) could be a promising strategy in reducing the incidence of CRC in patients with diabetes. However, available findings are inconclusive, and further studies are required. In this review, novel evidence on molecular mechanisms linking T2DM with CRC development, progression, and survival will be discussed. In addition, the potential role of GLP-1RAs therapies in CRC prevention will also be evaluated.  相似文献   
89.
This paper presents a method for analyzing the stability of small-signal microwave amplifiers with any topology. This analysis is performed using the Nyquist criterion and allows detection of the so-called odd-mode instabilities. The method is easily applicable by using commercially available microwave CAD. © 1998 John Wiley & Sons, Inc. Int J RF and Microwave CAE 8: 293–302, 1998.  相似文献   
90.
The fission yeast Schizosaccharomyces pombe is an excellent model organism for cell biology. However, its genetic toolbox is less developed than that of Saccharomyces cerevisiae. In the first part of this study we describe an improved inducible expression vector based on tetracycline regulation of the CaMV35S promoter, which is also capable of chromosomal integration and therefore works in minimal and in rich media. We found that anhydrotetracycline is a superior ligand for induction. Maximum expression levels were observed after 12 h in minimal media (EMM) and after 9 h in rich media (YES), which is faster than the nmt1 promoter system. The system was combined with a convenient recombineering-based subcloning strategy for ease of cloning. In the second part we present four template plasmids, pSVEM-bsd, pSVEM-nat, pSVEM-kan and pSVEM-hph, which harbour four recyclable disruption cassettes based on the Cre recombinase lox71/66 strategy for use in PCR targeting methods. Cre-mediated excision leaves a non-functional mutant lox site in the genome, allowing the reiterative usage of these cassettes for multiple targetings. These cassettes are also configured with dual eukaryotic/prokaryotic promoters so that they can be used for recombineering in E. coli. Amongst other purposes, this permits the rapid and convenient creation of targeting constructs with much longer homology arms for difficult and complex targetings in the Sz. pombe genome.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号