全文获取类型
收费全文 | 12398篇 |
免费 | 2411篇 |
国内免费 | 1547篇 |
专业分类
电工技术 | 1545篇 |
综合类 | 1277篇 |
化学工业 | 260篇 |
金属工艺 | 393篇 |
机械仪表 | 1115篇 |
建筑科学 | 206篇 |
矿业工程 | 104篇 |
能源动力 | 281篇 |
轻工业 | 85篇 |
水利工程 | 67篇 |
石油天然气 | 109篇 |
武器工业 | 472篇 |
无线电 | 3244篇 |
一般工业技术 | 832篇 |
冶金工业 | 196篇 |
原子能技术 | 29篇 |
自动化技术 | 6141篇 |
出版年
2024年 | 26篇 |
2023年 | 282篇 |
2022年 | 429篇 |
2021年 | 490篇 |
2020年 | 548篇 |
2019年 | 540篇 |
2018年 | 457篇 |
2017年 | 620篇 |
2016年 | 738篇 |
2015年 | 880篇 |
2014年 | 1072篇 |
2013年 | 933篇 |
2012年 | 1206篇 |
2011年 | 1200篇 |
2010年 | 924篇 |
2009年 | 820篇 |
2008年 | 853篇 |
2007年 | 874篇 |
2006年 | 709篇 |
2005年 | 558篇 |
2004年 | 398篇 |
2003年 | 354篇 |
2002年 | 324篇 |
2001年 | 243篇 |
2000年 | 184篇 |
1999年 | 126篇 |
1998年 | 104篇 |
1997年 | 75篇 |
1996年 | 69篇 |
1995年 | 60篇 |
1994年 | 54篇 |
1993年 | 43篇 |
1992年 | 32篇 |
1991年 | 23篇 |
1990年 | 22篇 |
1989年 | 13篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 8篇 |
1982年 | 3篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1964年 | 4篇 |
1963年 | 2篇 |
1961年 | 4篇 |
1960年 | 3篇 |
1956年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 615 毫秒
31.
为了解决全卷积孪生网络(SiamFC)跟踪算法在跟踪目标经历剧烈的外观变化时容易发生模型漂移从而导致跟踪失败的问题,提出了一种双重注意力机制孪生网络(DASiam)去调整网络模型并且不需要在线更新。首先,主干网络使用修改后表达能力更强的并适用于目标跟踪任务的VGG网络;然后,在网络的中间层加入一个新的双重注意力机制去动态地提取特征,这种机制由通道注意机制和空间注意机制组成,分别对特征图的通道维度和空间维度进行变换得到双重注意特征图;最后,通过融合两个注意机制的特征图进一步提升模型的表征能力。在三个具有挑战性的跟踪基准库即OTB2013、OTB100和2017年视觉目标跟踪库(VOT2017)实时挑战上进行实验,实验结果表明,以40 frame/s的速度运行时,所提算法在OTB2013和OTB100上的成功率指标比基准SiamFC分别高出3.5个百分点和3个百分点,并且在VOT2017实时挑战上面超过了2017年的冠军SiamFC,验证了所提出算法的有效性。 相似文献
32.
针对TLD(Tracking-Learning-Detection)算法在光照变化不均、遮挡严重、跟踪目标模糊等情况下会出现跟踪失败的问题,提出一种基于卷积神经网络优化TLD运动手势跟踪算法。选取手势特征作正样本,其背景作负样本,获取手势HOG特征并投入到卷积神经网络中加以训练,得到手势检测分类器,从而确定目标手势区域,实现手势的自动识别;再利用TLD算法对手势进行跟踪与学习,对正负样本进行估计检测并实时校正,同时运用SURF特征匹配更新跟踪器。实验结果验证,该算法对比TLD经典算法跟踪精度提高了4.24%,增强了运动手势的跟踪效果,相比经典跟踪算法拥有更高鲁棒性。 相似文献
33.
34.
35.
36.
Small group detection and tracking in crowd scenes are basis for high level crowd analysis tasks. However, it suffers from the ambiguities in generating proper groups and in handling dynamic changes of group configurations. In this paper, we propose a novel delay decision-making based method for addressing the above problems, motivated by the idea that these ambiguities can be solved using rich temporal context. Specifically, given individual detections, small group hypotheses are generated. Then candidate group hypotheses across consecutive frames and their potential associations are built in a tree. By seeking for the best non-conflicting subset from the hypothesis tree, small groups are determined and simultaneously their trajectories are got. So this framework is called joint detection and tracking. This joint framework reduces the ambiguities in small group decision and tracking by looking ahead for several frames. However, it results in the unmanageable solution space because the number of track hypotheses grows exponentially over time. To solve this problem, effective pruning strategies are developed, which can keep the solution space manageable and also improve the credibility of small groups. Experiments on public datasets demonstrate the effectiveness of our method. The method achieves the state-of-the-art performance even in noisy crowd scenes. 相似文献
37.
Artificial bee colony (ABC) algorithm has several characteristics that make it more attractive than other bio-inspired methods. Particularly, it is simple, it uses fewer control parameters and its convergence is independent of the initial conditions. In this paper, a novel artificial bee colony based maximum power point tracking algorithm (MPPT) is proposed. The developed algorithm, does not allow only overcoming the common drawback of the conventional MPPT methods, but it gives a simple and a robust MPPT scheme. A co-simulation methodology, combining Matlab/Simulink™ and Cadence/Pspice™, is used to verify the effectiveness of the proposed method and compare its performance, under dynamic weather conditions, with that of the Particle Swarm Optimization (PSO) based MPPT algorithm. Moreover, a laboratory setup has been realized and used to experimentally validate the proposed ABC-based MPPT algorithm. Simulation and experimental results have shown the satisfactory performance of the proposed approach. 相似文献
38.
Sag is a coating phenomenon characterized by gravity-driven flow after deposition; excessive amounts of sag can lead to coating defects. In this work, a new method for evaluating and quantifying sag is investigated. The motion of micron-sized Lycopodium spores on an inclined coating surface is tracked during drying, and the resulting surface velocity data is used to determine sag length. This in situ particle tracking method is minimally invasive and permits real time measurements. Measured sag lengths and real time surface velocities in aqueous polyvinyl alcohol solution coatings compare well with a theoretical model. The model is also used to develop a predictive sag regime map, which anticipates the extent of sag given coating properties and process-specific parameters. This map also identifies viable processing windows and aids in intelligent coating design given specific process constraints. The predictions of the sag regime map are compared against experimental sag results from polyvinyl alcohol solution coatings as well as four commercial latex paints, revealing good agreement for coatings with Newtonian or ‘Newtonian-like’ rheologies. 相似文献
39.
While creativity is essential for developing students’ broad expertise in Science, Technology, Engineering, and Math (STEM) fields, many students struggle with various aspects of being creative. Digital technologies have the unique opportunity to support the creative process by (1) recognizing elements of students’ creativity, such as when creativity is lacking (modeling step), and (2) providing tailored scaffolding based on that information (intervention step). However, to date little work exists on either of these aspects. Here, we focus on the modeling step. Specifically, we explore the utility of various sensing devices, including an eye tracker, a skin conductance bracelet, and an EEG sensor, for modeling creativity during an educational activity, namely geometry proof generation. We found reliable differences in sensor features characterizing low vs. high creativity students. We then applied machine learning to build classifiers that achieved good accuracy in distinguishing these two student groups, providing evidence that sensor features are valuable for modeling creativity. 相似文献
40.