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   114394篇
  免费   7115篇
  国内免费   4210篇
电工技术   4724篇
技术理论   1篇
综合类   7508篇
化学工业   15725篇
金属工艺   4471篇
机械仪表   5348篇
建筑科学   5791篇
矿业工程   1997篇
能源动力   2326篇
轻工业   8460篇
水利工程   2066篇
石油天然气   2844篇
武器工业   550篇
无线电   10439篇
一般工业技术   11090篇
冶金工业   24538篇
原子能技术   1176篇
自动化技术   16665篇
  2024年   277篇
  2023年   949篇
  2022年   1600篇
  2021年   2198篇
  2020年   1675篇
  2019年   1542篇
  2018年   2039篇
  2017年   2479篇
  2016年   2841篇
  2015年   3294篇
  2014年   3813篇
  2013年   4553篇
  2012年   6994篇
  2011年   7664篇
  2010年   5625篇
  2009年   5630篇
  2008年   5485篇
  2007年   5307篇
  2006年   5155篇
  2005年   7163篇
  2004年   5695篇
  2003年   4879篇
  2002年   4224篇
  2001年   3674篇
  2000年   2283篇
  1999年   2076篇
  1998年   7099篇
  1997年   4599篇
  1996年   3217篇
  1995年   2076篇
  1994年   1523篇
  1993年   1436篇
  1992年   515篇
  1991年   513篇
  1990年   486篇
  1989年   391篇
  1988年   404篇
  1987年   303篇
  1986年   237篇
  1985年   228篇
  1984年   114篇
  1983年   117篇
  1982年   153篇
  1981年   201篇
  1980年   210篇
  1979年   76篇
  1978年   107篇
  1977年   622篇
  1976年   1338篇
  1975年   107篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
In this paper, we present a novel memory access reduction scheme (MARS) for two-dimension fast cosine transform (2-D FCT). It targets programmable DSPs with high memory-access latency. It reduces the number of memory accesses by: 1) reducing the number of weighting factors and 2) combining butterflies in vector-radix 2-D FCT pruning diagram from two stages to one stage with an efficient structure. Hardware platform based on general purpose processor is used to verify the effectiveness of the proposed method for vector-radix 2-D FCT pruning implementation. Experimental results validate the benefits of the proposed method with reduced memory access, less clock cycle and fewer memory space compared with the conventional implementation.  相似文献   
2.
3.
We explore the possibility of characterizing sperm cells without the need to stain them using spectral and fluorescence lifetime analyses after multi-photon excitation in an insect model. The autofluorescence emission spectrum of sperm of the common bedbug, Cimex lectularius, was consistent with the presence of flavins and NAD(P)H. The mean fluorescence lifetimes showed smaller variation in sperm extracted from the male (tau m, τm = 1.54–1.84 ns) than in that extracted from the female sperm storage organ (tau m, τm = 1.26–2.00 ns). The fluorescence lifetime histograms revealed four peaks. These peaks (0.18, 0.92, 2.50 and 3.80 ns) suggest the presence of NAD(P)H and flavins and show that sperm metabolism can be characterized using fluorescence lifetime imaging. The difference in fluorescence lifetime variation between the sexes is consistent with the notion that female animals alter the metabolism of sperm cells during storage. It is not consistent, however, with the idea that sperm metabolism represents a sexually selected character that provides females with information about the male genotype.  相似文献   
4.
陈国亮  李宏  朱旭 《纺织器材》2015,42(1):61-62
为了解决钢丝圈挂花问题,阐述了LH001新型钢丝圈清洁器的特点和应用效果;通过试验说明使用新型钢丝圈清洁器断头率低,基本无挂花,纺纱效果好。指出:新型钢丝圈清洁器是普通钢丝圈清洁器的更新换代产品,值得推广。  相似文献   
5.
介绍锚杆应用及常用的拆锚方法,针对现有前混合磨料射流退锚装置存在锚杆拆卸时间长、工人作业环境差、装置部件锈蚀维护性差等问题,提出了一种前混合磨料射流退锚改进装置,并进行现场试验,结果表明,所改进设计装置具有退锚时间短、对工人伤害小、操作简便、部件维护周期长和无需专门配备泵站等特点,对进一步提高锚杆拆除效率具有重要参考价值。  相似文献   
6.
7.
8.
9.
Process object is the instance of process. Vertexes and edges are in the graph of process object. There are different types of the object itself and the associations between object. For the large-scale data, there are many changes reflected. Recently, how to find appropriate real-time data for process object becomes a hot research topic. Data sampling is a kind of finding c hanges o f p rocess o bjects. There i s r equirements f or s ampling to be adaptive to underlying distribution of data stream. In this paper, we have proposed a adaptive data sampling mechanism to find a ppropriate d ata t o m odeling. F irst o f all, we use concept drift to make the partition of the life cycle of process object. Then, entity community detection is proposed to find changes. Finally, we propose stream-based real-time optimization of data sampling. Contributions of this paper are concept drift, community detection, and stream-based real-time computing. Experiments show the effectiveness and feasibility of our proposed adaptive data sampling mechanism for process object.  相似文献   
10.
In the field of images and imaging, super-resolution (SR) reconstruction of images is a technique that converts one or more low-resolution (LR) images into a highresolution (HR) image. The classical two types of SR methods are mainly based on applying a single image or multiple images captured by a single camera. Microarray camera has the characteristics of small size, multi views, and the possibility of applying to portable devices. It has become a research hotspot in image processing. In this paper, we propose a SR reconstruction of images based on a microarray camera for sharpening and registration processing of array images. The array images are interpolated to obtain a HR image initially followed by a convolution neural network (CNN) procedure for enhancement. The convolution layers of our convolution neural network are 3×3 or 1×1 layers, of which the 1×1 layers are used to improve the network performance particularly. A bottleneck structure is applied to reduce the parameter numbers of the nonlinear mapping and to improve the nonlinear capability of the whole network. Finally, we use a 3×3 deconvolution layer to significantly reduce the number of parameters compared to the deconvolution layer of FSRCNN-s. The experiments show that the proposed method can not only ameliorate effectively the texture quality of the target image based on the array images information, but also further enhance the quality of the initial high resolution image by the improved CNN.  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