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   70290篇
  免费   6843篇
  国内免费   4108篇
电工技术   4167篇
技术理论   5篇
综合类   5297篇
化学工业   11699篇
金属工艺   4068篇
机械仪表   4363篇
建筑科学   4998篇
矿业工程   1857篇
能源动力   1666篇
轻工业   6788篇
水利工程   1464篇
石油天然气   3307篇
武器工业   584篇
无线电   8146篇
一般工业技术   8282篇
冶金工业   2953篇
原子能技术   796篇
自动化技术   10801篇
  2024年   367篇
  2023年   1191篇
  2022年   2128篇
  2021年   2830篇
  2020年   2187篇
  2019年   1905篇
  2018年   2113篇
  2017年   2338篇
  2016年   2141篇
  2015年   2936篇
  2014年   3642篇
  2013年   4464篇
  2012年   5014篇
  2011年   5506篇
  2010年   5040篇
  2009年   4979篇
  2008年   4711篇
  2007年   4464篇
  2006年   4156篇
  2005年   3522篇
  2004年   2495篇
  2003年   2051篇
  2002年   1995篇
  2001年   1659篇
  2000年   1360篇
  1999年   1264篇
  1998年   882篇
  1997年   734篇
  1996年   643篇
  1995年   546篇
  1994年   471篇
  1993年   347篇
  1992年   266篇
  1991年   220篇
  1990年   141篇
  1989年   152篇
  1988年   92篇
  1987年   64篇
  1986年   45篇
  1985年   27篇
  1984年   24篇
  1983年   16篇
  1982年   23篇
  1981年   10篇
  1980年   11篇
  1979年   12篇
  1978年   9篇
  1977年   10篇
  1976年   13篇
  1975年   9篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
This paper addresses the food distribution decision from a wholesaler's perspective, as the wholesalers are often faced with thorny issues such as when, where, how to deliver products at the lowest costs to best satisfy the retailers’ changing needs. This research relies on a distribution problem encountered at Northern Grocery Company in Beijing as an example to develop a two-stage solution procedure and subsequent computer-enabled programs for identifying efficient vehicle routing alternatives. The solution process, which integrates heuristic search algorithms and an integer programming model, can be applied to a wide range of distribution problems with specified route durations and a circular transportation network structure as exemplified by City of Beijing.  相似文献   
102.
103.
Large holes are unavoidably generated in depth image based rendering (DIBR) using a single color image and its associated depth map. Such holes are mainly caused by disocclusion, which occurs around the sharp depth discontinuities in the depth map. We propose a divide-and-conquer hole-filling method which refines the background depth pixels around the sharp depth discontinuities to address the disocclusion problem. Firstly, the disocclusion region is detected according to the degree of depth discontinuity, and the target area is marked as a binary mask. Then, the depth pixels located in the target area are modified by a linear interpolation process, whose pixel values decrease from the foreground depth value to the background depth value. Finally, in order to remove the isolated depth pixels, median filtering is adopted to refine the depth map. In these ways, disocclusion regions in the synthesized view are divided into several small holes after DIBR, and are easily filled by image inpainting. Experimental results demonstrate that the proposed method can effectively improve the quality of the synthesized view subjectively and objectively.  相似文献   
104.
Hu  Changhui  Lu  Xiaobo  Ye  Mengjun  Zeng  Weili  Du  Yijun 《Multimedia Tools and Applications》2017,76(24):26523-26550
Multimedia Tools and Applications - The extended sparse representation classifier (ESRC) is one of the state-of-the-art solutions for single sample face recognition, but it performs...  相似文献   
105.
Multimedia Tools and Applications - Sparse representation based classification (SRC) and collaborative representation based classification (CRC) are two well-known methods in representation-based...  相似文献   
106.
In this work, we aim to discover real-world events from Flickr data by devising a three-stage event detection framework. In the first stage, a multimodal fusion (MF) model is designed to deal with the heterogeneous feature modalities possessed by the user-shared data, which is advantageous in computation complexity. In the second stage, a dual graph regularized non-negative matrix factorization (DGNMF) model is proposed to learn compact feature representations. DGNMF incorporates Laplacian regularization terms for the data graph and base graph into the objective, keeping the geometry structures underlying the data samples and dictionary bases simultaneously. In the third stage, hybrid clustering algorithms are applied seamlessly to discover event clusters. Extensive experiments conducted on the real-world dataset reveal the MF-DGNMF-based approaches outperform the baselines.  相似文献   
107.
Universal Access in the Information Society - Helping blind people to build cognitive maps of an environment is one of the aims of several assistive systems. In order to evaluate such assistive...  相似文献   
108.
Opportunistic routing is a candidate for multihop wireless routing where the network topology and radio channels vary rapidly. However, there are not many opportunistic routing algorithms that can be implemented in a real multihop wireless network while exploiting the node mobility. It motivates us to implement an opportunistic routing, random basketball routing (BR), in a real multi-robot network to see if it can enhance the capacity of the multihop network as mobility increases. For implementation purposes, we added some features, such as destination RSSI measuring, a loop-free procedure and distributed relay probability updating, to the original BR. We carried out the experiments on a real multi-robot network and compared BR with AODV combined with CSMA/CA (routing + MAC protocol). We considered both static and dynamic scenarios. Our experiments are encouraging in that BR outperforms AODV + CSMA/CA, particularly in dynamic cases; the throughput of BR is 6.6 times higher than that of AODV + CSMA/CA. BR with dynamic networks shows 1.4 times higher throughput performance than BR with static networks. We investigate the performance of BR in the large-scale network using NS-2 simulation. We verify the effect of node density, speed, destination beacon signal and loop-free procedure. According to the large-scale simulation, the end-to-end throughput grows with the node speed.  相似文献   
109.
We propose a new approximate numerical algorithm for the steady-state solution of general structured ergodic Markov models. The approximation uses a state-space encoding based on multiway decision diagrams and a transition rate encoding based on a new class of edge-valued decision diagrams. The new method retains the favorable properties of a previously proposed Kronecker-based approximation, while eliminating the need for a Kronecker-consistent model decomposition. Removing this restriction allows for a greater utilization of event locality, which facilitates the generation of both the state-space and the transition rate matrix, thus extends the applicability of this algorithm to larger and more complex models.  相似文献   
110.
基于Linux的实时音频与视频传输   总被引:1,自引:0,他引:1  
讨论了多媒体会议中音频与视频的传输特性、要求和协议标准。并给出了程序实现。  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