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   1659篇
  免费   96篇
  国内免费   2篇
电工技术   10篇
综合类   3篇
化学工业   286篇
金属工艺   24篇
机械仪表   26篇
建筑科学   62篇
矿业工程   1篇
能源动力   39篇
轻工业   128篇
水利工程   24篇
石油天然气   4篇
武器工业   4篇
无线电   185篇
一般工业技术   347篇
冶金工业   316篇
原子能技术   11篇
自动化技术   287篇
  2024年   4篇
  2023年   26篇
  2022年   32篇
  2021年   48篇
  2020年   33篇
  2019年   43篇
  2018年   61篇
  2017年   46篇
  2016年   56篇
  2015年   45篇
  2014年   47篇
  2013年   116篇
  2012年   102篇
  2011年   150篇
  2010年   108篇
  2009年   106篇
  2008年   95篇
  2007年   91篇
  2006年   78篇
  2005年   66篇
  2004年   42篇
  2003年   35篇
  2002年   29篇
  2001年   21篇
  2000年   28篇
  1999年   28篇
  1998年   30篇
  1997年   25篇
  1996年   16篇
  1995年   12篇
  1994年   15篇
  1993年   8篇
  1990年   5篇
  1989年   5篇
  1988年   5篇
  1987年   5篇
  1985年   4篇
  1984年   8篇
  1983年   9篇
  1982年   7篇
  1981年   7篇
  1979年   5篇
  1976年   5篇
  1975年   3篇
  1974年   4篇
  1973年   4篇
  1972年   6篇
  1971年   3篇
  1970年   3篇
  1957年   3篇
排序方式: 共有1757条查询结果,搜索用时 31 毫秒
81.
The development of engineering students’ professional skills has gained considerable national attention from Accreditation Board for Engineering and Technology, the National Academy of Engineering, ASCE, and other constituents. There is little debate that these professional skills are necessary. Engineering programs have tried many approaches to develop these skills in the undergraduate programs. Colorado State University (CSU) has developed a new approach modeled on the type of professional development that occurs in the professional environment. This new Professional Learning Institute (PLI) provides students with a broad array of workshops, presentations, and experiential opportunities addressing the areas of cross cultural communication and teamwork, innovation, leadership, ethics, and public service. This program introduces students to the concept of professional development through required extracurricular activities, includes minimum requirements along with requirements to earn certificates in specialty areas for motivated students. The majority of offerings in the PLI are presented by leaders from the engineering profession who have teamed with CSU to provide high quality programs for our students.  相似文献   
82.
83.
X-ray powder diffraction, microscopy, thermal analysis and electron probe microanalysis were used to characterize a ZrO2-MgO inert matrix containing CeO2 as a homolog for PuO2 and Er2O3 as a burnable poison. The synthesis was carried out using a precipitation method. A large composition range of MgO to ZrO2 was evaluated to determine phases present, phase mixing, phase composition, microstructure and thermal properties. It was found that most compositions of the material consist of two phases: MgO (periclase) and ZrO2 (cubic zirconia). The zirconia phase incorporates 5% (wt/wt) MgO and up to 14% and 12% (wt/wt) CeO2 and Er2O3, respectively. The MgO phase remains pure, which will enable it to retain its heat transfer and solubility properties and will improve the overall thermal conductivity and reprocessing component of the inert matrix fuel. The results with Ce will be used as the basis of future studies with actinides.  相似文献   
84.
85.
Formalizing computational models for everyday human activities remains an open challenge. Many previous approaches towards this end assume prior knowledge about the structure of activities, using which explicitly defined models are learned in a completely supervised manner. For a majority of everyday environments however, the structure of the in situ activities is generally not known a priori. In this paper we investigate knowledge representations and manipulation techniques that facilitate learning of human activities in a minimally supervised manner. The key contribution of this work is the idea that global structural information of human activities can be encoded using a subset of their local event subsequences, and that this encoding is sufficient for activity-class discovery and classification.In particular, we investigate modeling activity sequences in terms of their constituent subsequences that we call event n-grams. Exploiting this representation, we propose a computational framework to automatically discover the various activity-classes taking place in an environment. We model these activity-classes as maximally similar activity-cliques in a completely connected graph of activities, and describe how to discover them efficiently. Moreover, we propose methods for finding characterizations of these discovered classes from a holistic as well as a by-parts perspective. Using such characterizations, we present a method to classify a new activity to one of the discovered activity-classes, and to automatically detect whether it is anomalous with respect to the general characteristics of its membership class. Our results show the efficacy of our approach in a variety of everyday environments.  相似文献   
86.
In this paper, we consider a new background elimination method for Raman spectra. The proposed method is based on peak detection, smoothing, and interpolation. Since the background is usually slowly varying with respect to wavelength, we could estimate the background by eliminating significant peaks. For this purpose, we seek the peaks by inspecting the smoothed derivative of a given spectrum. After clipping out the corresponding peak regions, we estimate the background by applying a modified linear interpolation. Then the background is eliminated from the measured Raman spectrum by simple subtraction. The experimental results showed that the proposed method gave satisfactory results for real Raman spectra as well as synthetic data. As the proposed method requires no prior knowledge of spectrum, we expect that the method could be applied to other spectral data as well.  相似文献   
87.
The efficacy of lauric arginate (LAE) on Salmonella survivability in ground chicken containing 9.8% fat was determined under refrigerated storage. The effect of LAE treatments on total aerobes, pH and objective colour were also assessed in ground chicken. LAE was highly effective against Salmonella in 0.1% peptone with no detectable survivors following treatment with 200 ppm and 400 ppm of LAE. No difference existed (P > 0.05) in the growth of Salmonella and total aerobes after treatment with 200 and 400 ppm of LAE in ground chicken inoculated with a four strain mixture of Salmonella. At these concentrations, LAE did not exhibit any treatment effect on the pH and colour of ground chicken (P > 0.05). In conclusion, although LAE possesses strong inhibitory (P < 0.05) effect against Salmonella in suspension in 0.1% peptone water, no inhibitory (P > 0.05) effect on growth of Salmonella was observed in ground chicken at the currently approved levels of 200 ppm of LAE.  相似文献   
88.
Pervasive systems are large-scale systems consisting of many sensors capturing numerous types of information. As this data is highly voluminous and dimensional, data analysis tasks can be extremely cumbersome and time-consuming. Enabling computers to recognise real-world situations is an even more difficult problem, involving not only data analysis, but also consistency checking. Here we present Situvis, an interactive visualisation tool for representing sensor data and creating higher-level abstractions from the data. This paper builds on previous work, Clear et al. (2009) [8] through evolved tool functionality and an evaluation of Situvis. A user-trial consisting of 10 participants shows that Situvis can be used to complete the key tasks in the development process of situation specifications in over 50% less time than an improvised alternative toolset.  相似文献   
89.
球珊阵列(BGAs)在印刷电路板(PCB)组件上已经相当常见,进而带来了新的故障模式,要求新的分析工具或方法,以便正确评估这些元件。传统式SMT元件,如SOICs或OFPs,允许以可视方式检测焊点,查找异常情况;而BGAs则做不到这一点,因为大多数焊点隐藏在元件下面,人眼是看不到的。本文讨论了STI实验室遇到的部分故障模式,以及进行调查使用的工具和方法。  相似文献   
90.
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