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   11617篇
  免费   895篇
  国内免费   34篇
电工技术   198篇
综合类   9篇
化学工业   3050篇
金属工艺   480篇
机械仪表   727篇
建筑科学   208篇
矿业工程   2篇
能源动力   581篇
轻工业   1023篇
水利工程   33篇
石油天然气   8篇
武器工业   2篇
无线电   1925篇
一般工业技术   2721篇
冶金工业   469篇
原子能技术   161篇
自动化技术   949篇
  2024年   13篇
  2023年   143篇
  2022年   192篇
  2021年   341篇
  2020年   300篇
  2019年   322篇
  2018年   408篇
  2017年   372篇
  2016年   469篇
  2015年   353篇
  2014年   563篇
  2013年   784篇
  2012年   873篇
  2011年   997篇
  2010年   709篇
  2009年   781篇
  2008年   708篇
  2007年   544篇
  2006年   444篇
  2005年   413篇
  2004年   352篇
  2003年   342篇
  2002年   300篇
  2001年   252篇
  2000年   230篇
  1999年   215篇
  1998年   238篇
  1997年   182篇
  1996年   128篇
  1995年   112篇
  1994年   80篇
  1993年   70篇
  1992年   46篇
  1991年   30篇
  1990年   39篇
  1989年   36篇
  1988年   29篇
  1987年   20篇
  1986年   20篇
  1985年   19篇
  1984年   13篇
  1983年   12篇
  1982年   8篇
  1981年   5篇
  1980年   5篇
  1979年   6篇
  1977年   6篇
  1976年   10篇
  1975年   5篇
  1973年   2篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
The purpose of this study was to investigate the effect of wheelchair-based rehabilitation on the physical functions, health perception, and blood lipids according to the length of time since the stroke. Wheelchair-based rehabilitation progressed for 60 min per session, five times per week for 6 weeks. Physical functions, health perception (SF-36), and blood lipids were measured before and after rehabilitation. Physical fitness for physical function such as agility, grip strength, lower-body muscular endurance, flexibility, and posture control significantly improved after 6 weeks of rehabilitation. Health perception improved significantly with physical and mental health according to time since the stroke occurred. Overall, 6 weeks of wheelchair-based rehabilitation had a positive effect on the physical function and health perception regardless of stroke duration. Wheelchair-based rehabilitation had a more positive effect on the physical functions and health perception on the patients who suffered their stroke most recently. We suggested that wheelchair-based rehabilitation is necessary even through wheelchair based for chronic stroke patients, and it was useful their improved of quality of life.  相似文献   
92.
In this paper, we present a personal area situation understanding (PASU) system, a novel application of a smart device using wireless camera sensor networks. The portability of a PASU system makes it an attractive solution for monitoring and understanding the current situation of the personal area around a user. The PASU system allows its user to construct a 3D scene of the environment and view the scene from various vantage points for better understanding of the environment. The paper describes the architecture and implementation of the PASU system addressing limitations of wireless camera sensor networks, such as low bandwidth and limited computational capabilities. The capabilities of PASU are validated with extensive experiments. The PASU system demonstrates the potential of a portable system combining a smart device and a wireless camera sensor network for personal area monitoring and situation understanding.  相似文献   
93.
A hidden‐picture puzzle contains objects hidden in a background image, in such a way that each object fits closely into a local region of the background. Our system converts image of the background and objects into line drawing, and then finds places in which to hide transformed versions of the objects using rotation‐invariant shape context matching. During the hiding process, each object is subjected to a slight deformation to enhance its similarity to the background. The results were assessed by a panel of puzzle‐solvers.  相似文献   
94.
It is foreseen that more and more music objects in symbolic format and multimedia objects, such as audio, video, or lyrics, integrated with symbolic music representation (SMR) will be published and broadcasted via the Internet. The SMRs of the flowing songs or multimedia objects will form a music stream. Many interesting applications based on music streams, such as interactive music tutorials, distance music education, and similar theme searching, make the research of content-based retrieval over music streams much important. We consider multiple queries with error tolerances over music streams and address the issue of approximate matching in this environment. We propose a novel approach to continuously process multiple queries over the music streams for finding all the music segments that are similar to the queries. Our approach is based on the concept of n-grams, and two mechanisms are designed to reduce the heavy computation of approximate matching. One mechanism uses the clustering of query n-grams to prune the query n-grams that are irrelevant to the incoming data n-gram. The other mechanism records the data n-gram that matches a query n-gram as a partial answer and incrementally merges the partial answers of the same query. We implement a prototype system for experiments in which songs in the MIDI format are continuously broadcasted, and the user can specify musical segments as queries to monitor the music streams. Experiment results show the effectiveness and efficiency of the proposed approach.  相似文献   
95.
Memory-based collaborative filtering (CF) recommender systems have emerged as an effective technique for information filtering. CF recommenders are being widely adopted for e-commerce applications to assist users in finding and selecting items of interest. As a result, the scalability of CF recommenders presents a significant challenge; one that is particularly resilient because the volume of data these systems utilize will continue to increase over time. This paper examines the impact of discrete wavelet transformation (DWT) as an approach to enhance the scalability of memory-based collaborative filtering recommender systems. In particular, a wavelet transformation methodology is proposed and applied to both synthetic and real-world recommender ratings. For experimental purposes, the DWT methodology’s effect on predictive accuracy and calculation speed is evaluated to compare recommendation quality and performance.  相似文献   
96.
Abstract— A new digital ambient‐light sensor system is presented which employs two linear light sensors with different sensitivities and automatically adjusts the sensitivity based on the illumination condition. The adaptation mechanism allows a very wide range of light intensity to be detected, and the input dynamic range of the system is substantially improved from 22.5 to 45.1 dB. The proposed method does not require any additional precision bits for output data. Due to the small number of the output bits and the simple conversion process, the system can be easily integrated on the display panel.  相似文献   
97.
Abstract— A touch‐screen‐panel (TSP) embedded 12.1‐in. LCD employing a standard existing a‐Si:H TFT‐LCD process has been successfully developed. Compared with conventional external touch‐screen panels, which use additional components to detect touch events, the new internal TSP exhibits a clearer image and improved touch feeling, as well as increased sensing speed using discrete sensing lines to enable higher‐speed sensing functions including handwriting. The new internal digital switching TSP can be fabricated with low cost because it does not require any additional process steps compared to a standard a‐Si:H TFT‐LCD.  相似文献   
98.
Abstract— The dynamic performance of displays is an important characteristic for multimedia applications. Motion‐picture response time (MPRT) has been used as an indicator of the dynamic performance of LCDs. This paper describes a comprehensive method of MPRT evaluation for the oblique viewing direction. By using a tilted camera configuration, the angular dependency of MPRT is investigated for the condition that the horizontally scrolling patterns are observed from the vertical direction. For each gray‐to‐gray transition, distinct changes in MPRT and the luminance profile of blur are observed.  相似文献   
99.
Abstract— This study covers thin‐film barriers using inorganic barriers of transparent conducting oxides (TCOs) such as zinc oxide (ZnO) and indium tin oxide (ITO). The TCOs were fabricated using a sputtering method with a process gas of pure argon at room temperature. ITO showed better properties as a barrier than the ZnO and exhibited the electronic performance necessary to perform additional functions. The ITO has superior barrier performance because it has a lower crack density due to its partial amorphous phase. For organic/inorganic multilayer barriers, the organic underlayer decreased the water‐vapor transmission rate (WVTR) more than the organic upper layer, indicating that the planarization effect was important in reducing the WVTRs. The results of this organic/ITO multilayer barrier study are expected to be useful in finding a practical solution to OLED encapsulation.  相似文献   
100.
We present an interactive algorithm for continuous collision detection between deformable models. We introduce multiple techniques to improve the culling efficiency and the overall performance of continuous collision detection. First, we present a novel formulation for continuous normal cones and use these normal cones to efficiently cull large regions of the mesh as part of self-collision tests. Second, we introduce the concept of “procedural representative triangles” to remove all redundant elementary tests between nonadjacent triangles. Finally, we exploit the mesh connectivity and introduce the concept of “orphan sets” to eliminate redundant elementary tests between adjacent triangle primitives. In practice, we can reduce the number of elementary tests by two orders of magnitude. These culling techniques have been combined with bounding volume hierarchies and can result in one order of magnitude performance improvement as compared to prior collision detection algorithms for deformable models. We highlight the performance of our algorithm on several benchmarks, including cloth simulations, N-body simulations, and breaking objects.  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