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   1519篇
  免费   48篇
  国内免费   1篇
电工技术   19篇
综合类   4篇
化学工业   210篇
金属工艺   17篇
机械仪表   68篇
建筑科学   68篇
能源动力   52篇
轻工业   87篇
水利工程   10篇
石油天然气   1篇
无线电   220篇
一般工业技术   320篇
冶金工业   209篇
原子能技术   9篇
自动化技术   274篇
  2023年   6篇
  2022年   20篇
  2021年   32篇
  2020年   28篇
  2019年   25篇
  2018年   25篇
  2017年   36篇
  2016年   41篇
  2015年   23篇
  2014年   34篇
  2013年   106篇
  2012年   59篇
  2011年   87篇
  2010年   61篇
  2009年   52篇
  2008年   68篇
  2007年   66篇
  2006年   75篇
  2005年   73篇
  2004年   52篇
  2003年   55篇
  2002年   42篇
  2001年   31篇
  2000年   32篇
  1999年   39篇
  1998年   62篇
  1997年   51篇
  1996年   35篇
  1995年   34篇
  1994年   26篇
  1993年   17篇
  1992年   11篇
  1991年   17篇
  1990年   6篇
  1989年   14篇
  1988年   12篇
  1987年   19篇
  1986年   12篇
  1985年   17篇
  1984年   4篇
  1983年   6篇
  1981年   8篇
  1980年   7篇
  1979年   4篇
  1978年   3篇
  1977年   7篇
  1976年   10篇
  1974年   4篇
  1973年   3篇
  1969年   3篇
排序方式: 共有1568条查询结果,搜索用时 15 毫秒
1.
International Journal of Computer Vision - We propose a novel CNN architecture called ACTNET for robust instance image retrieval from large-scale datasets. Our key innovation is a learnable...  相似文献   
2.
In this letter, a concise process technology is proposed for the first time to enable the fabrication of good quality three-dimensional (3-D) suspended radio frequency (RF) micro-inductors on bulk silicon, without utilizing the lithography process on sidewall and trench-bottom patterning. Samples were fabricated to demonstrate the applicability of the proposed process technology.  相似文献   
3.
Some of the factors affecting cloud point determination of palm oleins are described. These are the type of container used, method of stirring, rate of stirring and bath temperature. The repeatability and reproducibility standard deviations of the method are determined from collaborative trials. Recommendations for the test are made to reduce the large variations among laboratories.  相似文献   
4.
The authors examine effects on the torque that simple variations of the standard rotor pole face profile could have, basically from an elementary viewpoint of how the modified profiles affect the distribution and magnitude of the radial and tangential components of the flux density. It is observed that the average torque is mostly affected by changes that alter the dominant radial component, such as changes in the effective air gap length. The other observation that an increase in the average torque can also be obtained by a favorable shift in the torque versus angle characteristics by relatively simple changes of the rotor pole profile is not so well known. Such a shift that reduces the slope of the torque angle characteristic, skewing the curve towards the unaligned position, has two advantages: one is that the phase inductance is at its maximum positive slop and, hence, the maximum torque, when the phase is energized; second, the flatter inductance profile near the aligned position when the phase current is to be commutated would allow a faster drop off of the commutated current and, thus, a smaller negative torque  相似文献   
5.
6.
A deterministic digital simulation model with finite sum of properly weighted sinusoids is used to simulate a frequency nonselective mobile channel with LOS component. Measurement data are used to optimise the parameters. Which are then used in the deterministic simulation model. The probability distribution and level cross rate (LCR) obtained from the measured data agree well with the analytical and simulation results  相似文献   
7.
Although the meninges are often thought of simplistically as a connective tissue sac that contains the CSF and the contents of the CNS, they are far more complex. Anatomically, they comprise several layers. Pathologically, numerous disease processes may affect the meninges; different processes may even involve different areas of the meninges. These factors all influence the MR imaging characteristics of meningeal lesions. This review briefly discusses the anatomy of the meninges, the MR imaging technique when meningeal disease is suspected, and the appearance of the normal meninges. It then focuses on tumors, infections, cysts, and other lesions that primarily involve the meninges, excluding lesions that secondarily involve the meninges.  相似文献   
8.
This paper presents eight‐node solid‐shell elements for geometric non‐linear analysis of elastic shells. To subdue shear, trapezoidal and thickness locking, the assumed natural strain method and an ad hoc modified generalized laminate stiffness matrix are employed. A selectively reduced integrated element is formulated with its membrane and bending shear strain components taken to be constant and equal to the ones evaluated at the element centroid. With the generalized stresses arising from the modified generalized laminate stiffness matrix assumed to be independent from the ones obtained from the displacement, an extended Hellinger–Reissner functional can be derived. By choosing the assumed generalized stresses similar to the assumed stresses of a previous solid element, a hybrid‐stress solid‐shell element is formulated. Commonly employed geometric non‐linear homogeneous and laminated shell problems are attempted and our results are close to those of other state‐of‐the‐art elements. Moreover, the hybrid‐stress element converges more readily than the selectively reduced integrated element in all benchmark problems. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
9.
The authors have exploited the ideas used in vector quantisation for error recovery of scalar quantised LSFs. The good performance of this method has provided high resistance of the LSFs to channel errors, outperforming other schemes by, possibly, a considerable margin. Better objective and subjective performances were obtained with this new method which obviates the need for more powerful FEC schemes for transmission over noisy channels.<>  相似文献   
10.
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