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   2496篇
  免费   130篇
  国内免费   8篇
电工技术   41篇
综合类   3篇
化学工业   603篇
金属工艺   33篇
机械仪表   50篇
建筑科学   85篇
矿业工程   5篇
能源动力   96篇
轻工业   256篇
水利工程   38篇
石油天然气   10篇
无线电   195篇
一般工业技术   358篇
冶金工业   347篇
原子能技术   18篇
自动化技术   496篇
  2023年   36篇
  2022年   95篇
  2021年   118篇
  2020年   78篇
  2019年   71篇
  2018年   71篇
  2017年   80篇
  2016年   81篇
  2015年   82篇
  2014年   70篇
  2013年   157篇
  2012年   159篇
  2011年   162篇
  2010年   110篇
  2009年   117篇
  2008年   102篇
  2007年   107篇
  2006年   97篇
  2005年   80篇
  2004年   73篇
  2003年   47篇
  2002年   54篇
  2001年   35篇
  2000年   21篇
  1999年   38篇
  1998年   97篇
  1997年   62篇
  1996年   45篇
  1995年   26篇
  1994年   25篇
  1993年   27篇
  1992年   9篇
  1991年   17篇
  1990年   12篇
  1989年   19篇
  1988年   9篇
  1987年   14篇
  1986年   13篇
  1985年   8篇
  1984年   11篇
  1983年   10篇
  1982年   5篇
  1981年   7篇
  1980年   16篇
  1978年   4篇
  1977年   5篇
  1976年   12篇
  1975年   5篇
  1974年   7篇
  1972年   4篇
排序方式: 共有2634条查询结果,搜索用时 31 毫秒
11.
In this paper, an efficient implementation of the spectral domain moment technique is presented for computing the self and mutual coupling between slot antennas on a dielectric half-space. It is demonstrated that by the proper selection of the weighting functions in the method of moments, the analytic evaluation or simplification of the transverse moment integrals is enabled. This results into a significant reduction of the required computational labor. The method is then utilized in order to provide design data for the self and mutual admittances between two slot antennas on a dielectric substrate lens in the case of fused quartz (∈ r =3.80), crystal quartz (∈ r =4.53), silicon (∈ r =11.9) and GaAs (∈ r =12.8). The presented technique and associated results are useful when designing twin slot quasi-optical receivers, imaging arrays, phased arrays or power-combining arrays of slot elements at millimeter-wave frequencies.  相似文献   
12.
13.
Techniques which are currently used to measure skeletal muscle blood flow (SMBF) in patients with congestive heart failure (CHF) are neither convenient nor accurate. They have led to discrepant results in patients with congestive heart failure and are, in part, responsible for the ongoing debate regarding the factors which limit the rise in body oxygen consumption during exercise in these patients. However, direct measurement of SMBF may not be needed during exercise in patients with severe CHF. Their skeletal muscles maximally extract oxygen. Consequently, increase in oxygen consumption by the skeletal muscles is only mediated by a concomitant increase in SMBF. In patients with severe CHF, peak body oxygen consumption attained during maximal exercise closely depends on the rise in SMBF, and thus provides an indirect measurement of SMBF.  相似文献   
14.
A micromechanics analysis is performed for the determination of the five independent elastic moduli of unidirectional fiber composites. By considering viscoelastic phases and by using the correspondence principle and the inversion of the Laplace transform, the five time-dependent functions which characterize the effective behavior of viscoelastic composites are established. The predicted time-dependent behavior is applied for the analysis of viscoelastic laminated plates. The resulting viscoelastic effects are shown, and comparison between the results obtained within the classical laminated plate theory and the first-order shear deformation theory is discussed.  相似文献   
15.
Gabriel Wainer 《Software》2002,32(13):1261-1306
The features of a toolkit for modeling and simulation based on the DEVS formalism are presented. The tool is built as a set of independent software pieces running on different platforms. Not only are the main characteristics of the environment presented, a focus on its use is also considered by inclusion of application examples for a variety of problems. Many models can be defined in an automated fashion, simplifying the construction of new models and easing their verification. The use of this formal approach has allowed the development of safe and cost‐effective simulations, significantly reducing development time. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
16.
17.
18.
We present an algorithm for detecting periodicity in sequences produced by repeated application of a given function. Our algorithm uses logarithmic memory with high probability, runs in linear time, and is guaranteed to stop within the second loop through the cycle. We also present a partitioning technique that offers a time/memory tradeoff. Our algorithm is especially well suited for sequences where the cycle length is typically small compared to the length of the acyclic prefix.  相似文献   
19.
20.
This paper presents a new approach to the blind deconvolution and superresolution problem of multiple degraded low-resolution frames of the original scene. We do not assume any prior information about the shape of degradation blurs. The proposed approach consists of building a regularized energy function and minimizing it with respect to the original image and blurs, where regularization is carried out in both the image and blur domains. The image regularization based on variational principles maintains stable performance under severe noise corruption. The blur regularization guarantees consistency of the solution by exploiting differences among the acquired low-resolution images. Several experiments on synthetic and real data illustrate the robustness and utilization of the proposed technique in real applications.  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