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   374篇
  免费   14篇
  国内免费   3篇
电工技术   4篇
化学工业   57篇
金属工艺   2篇
机械仪表   2篇
建筑科学   8篇
能源动力   6篇
轻工业   12篇
水利工程   2篇
石油天然气   2篇
无线电   60篇
一般工业技术   54篇
冶金工业   32篇
自动化技术   150篇
  2023年   2篇
  2022年   7篇
  2021年   7篇
  2020年   4篇
  2019年   4篇
  2018年   8篇
  2017年   6篇
  2016年   15篇
  2015年   14篇
  2014年   10篇
  2013年   18篇
  2012年   13篇
  2011年   16篇
  2010年   14篇
  2009年   21篇
  2008年   22篇
  2007年   20篇
  2006年   22篇
  2005年   15篇
  2004年   15篇
  2003年   10篇
  2002年   12篇
  2001年   5篇
  2000年   8篇
  1999年   8篇
  1998年   10篇
  1997年   13篇
  1996年   7篇
  1995年   8篇
  1994年   4篇
  1993年   7篇
  1992年   2篇
  1991年   5篇
  1990年   1篇
  1989年   2篇
  1988年   3篇
  1987年   3篇
  1986年   3篇
  1985年   3篇
  1984年   3篇
  1983年   2篇
  1982年   1篇
  1979年   4篇
  1978年   3篇
  1976年   2篇
  1974年   1篇
  1972年   1篇
  1971年   2篇
  1969年   3篇
  1968年   2篇
排序方式: 共有391条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
We present a verb–complement dictionary of Modern Hebrew, automatically extracted from text corpora. Carefully examining a large set of examples, we defined ten types of verb complements that cover the vast majority of the occurrences of verb complements in the corpora. We explored several collocation measures as indicators of the strength of the association between the verb and its complement. We then used these measures to automatically extract verb complements from corpora. The result is a wide-coverage, accurate dictionary that lists not only the likely complements for each verb, but also the likelihood of each complement. We evaluated the quality of the extracted dictionary both intrinsically and extrinsically. Intrinsically, we showed high precision and recall on randomly (but systematically) selected verbs. Extrinsically, we showed that using the extracted information is beneficial for two applications, prepositional phrase attachment disambiguation and Arabic-to-Hebrew machine translation.  相似文献   
95.
This paper describes a thermal multi-scale formulation for composite materials based on a mechanical homogenization approach. The presented formulation evaluates the effective macroscopic thermal conductivity of the composite materials and also the microscopic heat flux field by scaling down to the micro-scale level. The effective thermal conductivity of the composite materials was calculated by applying the homogenization theory over the unit cell. The uniqueness of the presented multi-scale analysis related to the elastic problems solved at the microscopic scale (unit cell). This method has the advantage of applying periodic boundary conditions and uniform macroscopic temperature gradient over the unit cell. The proposed thermal multi-scale analysis was verified and its efficiency was demonstrated on large scale problem.  相似文献   
96.
97.
The relationship between Doppler measurements, size and growth rate in fetal growth restriction has not been defined. We used functional linear discriminant analysis (FLDA) to investigate these parameters taking account of the difficulties inherent in exploring relationships between repeated observations from a small number of cases. In 40 fetuses with severe growth restriction, serial abdominal circumference (AC), umbilical, middle cerebral artery (MCA) and ductus venosus Doppler pulsatility index measurements were recorded. In 11 singleton fetuses with normal growth, umbilical artery pulsatility index only was measured. Data were expressed as z-scores in relation to gestation and analysed longitudinally using FLDA. In severe growth restriction, the Spearman correlation coefficients between umbilical artery pulsatility index and AC z-score, MCA pulsatility index and AC z-score and ductus venosus pulsatility index z-score and AC z-score were, respectively: −0.36, p = 4.4 × 10−7; 0.70, p = 1.1 × 10−17 and −0.50, p = 8.1 × 10−4. No relationship was seen between Doppler parameters and growth rate. There was no relationship between umbilical artery pulsatility index and AC nor growth rate in normally grown fetuses. In severe fetal growth restriction, Doppler changes are related to absolute fetal AC size, not growth rate.  相似文献   
98.
Digital library information-technology infrastructures   总被引:2,自引:1,他引:1  
This paper charts a research agenda on systems-oriented issues in digital libraries. It focuses on the most central and generic system issues, including system architecture, user-level functionality, and the overall operational environment. With respect to user-level functionality, in particular, it abstracts the overall information lifecycle in digital libraries to five major stages and identifies key research problems that require solution in each stage. Finally, it recommends an explicit set of activities that would help achieve the research goals outlined and identifies several dimensions along which progress of the digital library field can be evaluated.  相似文献   
99.
Log‐domain filters are an intriguing form of externally linear, internally nonlinear current‐mode circuits, in which a compression stage is first used to convert the input currents to the logarithmic domain, then analogue processing is carried out on the resulting voltages, and finally input–output linearity is restored by mapping the output voltages to current form through an expansion stage. The compressing and expanding operations confer on log‐domain filters a number of desirable features, but they may be responsible for the loss of external linearity. In this paper, sufficient conditions for the external linearity of log‐domain LC‐ladders are established, and the local nature of this external linearity is highlighted. Certain log‐domain LC‐ladders employing floating capacitors may exhibit externally nonlinear behaviour even for zero input and very small initial conditions. We show how transistor parasitic capacitances are central to the emergence of this behaviour, and must be incorporated in the circuit model. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
100.
In this work we explored class separability in feature spaces built on extended representations of pixel planes (EPP) produced using scale pyramid, subband pyramid, and image transforms. The image transforms included Chebyshev, Fourier, wavelets, gradient, and Laplacian; we also utilized transform combinations, including Fourier, Chebyshev, and wavelets of the gradient transform, as well as Fourier of the Laplacian transform. We demonstrate that all three types of EPP promote class separation. We also explored the effect of EPP on suboptimal feature libraries, using only textural features in one case and only Haralick features in another. The effect of EPP was especially clear for these suboptimal libraries, where the transform-based representations were found to increase separability to a greater extent than scale or subband pyramids. EPP can be particularly useful in new applications where optimal features have not yet been developed.  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