全文获取类型
收费全文 | 4388篇 |
免费 | 801篇 |
国内免费 | 329篇 |
专业分类
电工技术 | 123篇 |
综合类 | 501篇 |
化学工业 | 109篇 |
金属工艺 | 150篇 |
机械仪表 | 298篇 |
建筑科学 | 323篇 |
矿业工程 | 50篇 |
能源动力 | 44篇 |
轻工业 | 5篇 |
水利工程 | 240篇 |
石油天然气 | 146篇 |
武器工业 | 511篇 |
无线电 | 610篇 |
一般工业技术 | 712篇 |
冶金工业 | 84篇 |
原子能技术 | 30篇 |
自动化技术 | 1582篇 |
出版年
2024年 | 40篇 |
2023年 | 137篇 |
2022年 | 170篇 |
2021年 | 138篇 |
2020年 | 167篇 |
2019年 | 148篇 |
2018年 | 144篇 |
2017年 | 160篇 |
2016年 | 211篇 |
2015年 | 202篇 |
2014年 | 329篇 |
2013年 | 276篇 |
2012年 | 373篇 |
2011年 | 414篇 |
2010年 | 320篇 |
2009年 | 258篇 |
2008年 | 259篇 |
2007年 | 317篇 |
2006年 | 248篇 |
2005年 | 218篇 |
2004年 | 163篇 |
2003年 | 147篇 |
2002年 | 133篇 |
2001年 | 103篇 |
2000年 | 99篇 |
1999年 | 55篇 |
1998年 | 57篇 |
1997年 | 29篇 |
1996年 | 53篇 |
1995年 | 33篇 |
1994年 | 24篇 |
1993年 | 24篇 |
1992年 | 14篇 |
1991年 | 13篇 |
1990年 | 9篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1962年 | 1篇 |
1961年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有5518条查询结果,搜索用时 0 毫秒
41.
42.
The paper presents a new approach for recommending suitable learning paths for different learners groups. Selection of the learning path is considered as recommendations to choosing and combining the sequences of learning objects (LOs) according to learners’ preferences. Learning path can be selected by applying artificial intelligence techniques, e.g. a swarm intelligence model. If we modify and/or change some LOs in the learning path, we should rearrange the alignment of new and old LOs and reallocate pheromones to achieve effective learning recommendations. To solve this problem, a new method based on the ant colony optimisation algorithm and adaptation of the solution to the changing optimum is proposed. A simulation process with a dynamic change of learning paths when new LOs are inserted was chosen to verify the method proposed. The paper contributes with the following new developments: (1) an approach of dynamic learning paths selection based on swarm intelligence, and (2) a modified ant colony optimisation algorithm for learning paths selection. The elaborated approach effectively assist learners by helping them to reach most suitable LOs according to their preferences, and tutors – by helping them to monitor, refine, and improve e-learning modules and courses according to the learners’ behaviour. 相似文献
43.
Halil Akçakaya 《Advanced Robotics》2014,28(9):601-611
Set point tracking control of autonomous underwater vehicle (AUV) via robust model predictive control (RMPC) is considered. Input-constrained RMPC with integral action, which has been developed in our previous work, is used to control the AUV in this study. In order to derive a RMPC control rule, non-linear dynamics of AUV with six degree of freedom is linearized at certain operating points. So, horizontal and vertical plane dynamics of system are represented by linear models which have polytopic uncertainties. Since the derived control rule will be used in real time, the computation time should be reduced. To overcome this computational time problem and get rid of trial–error step of Algorithm 1, a new algorithm is proposed here. The simulations are carried out using the control rule based on this algorithm and these results are presented. 相似文献
44.
针对水下运动体测速中存在的难度大、精度低等问题,提出一种基于加速度计和机械测速装置的融合测速方法。该方法实质上是一种改良的模糊自适应卡尔曼滤波,在常规卡尔曼滤波的基础上,引入了自适应参数,并通过模糊控制器对残差的监控来实时调整自适应参数。经Matlab仿真和实际试验证实:该方法可以有效地提高卡尔曼滤波器的跟踪性,并改善滤波效果,适用于通用的水下运动体测速。 相似文献
45.
46.
47.
48.
In this paper, we propose a discriminative multi-task objects tracking method with active feature selection and drift correction. The developed method formulates object tracking in a particle filter framework as multi-Task discriminative tracking. As opposed to generative methods that handle particles separately, the proposed method learns the representation of all the particles jointly and the corresponding coefficients are similar. The tracking algorithm starts from the active feature selection scheme, which adaptively chooses suitable number of discriminative features from the tracked target and background in the dynamic environment. Based on the selected feature space, the discriminative dictionary is constructed and updated dynamically. Only a few of them are used to represent all the particles at each frame. In other words, all the particles share the same dictionary templates and their representations are obtained jointly by discriminative multi-task learning. The particle that has the highest similarity with the dictionary templates is selected as the next tracked target state. This jointly sparsity and discriminative learning can exploit the relationship between particles and improve tracking performance. To alleviate the visual drift problem encountered in object tracking, a two-stage particle filtering algorithm is proposed to complete drift correction and exploit both the ground truth information of the first frame and observations obtained online from the current frame. Experimental evaluations on challenging sequences demonstrate the effectiveness, accuracy and robustness of the proposed tracker in comparison with state-of-the-art algorithms. 相似文献
49.
We address the problem of robust and efficient treatment of element collapse and inversion in corotational FEM simulations of deformable objects in two and three dimensions, and show that existing degeneration treatment methods have previously unreported flaws that seriously threaten robustness and physical plausibility in interactive applications. We propose a new method that avoids such flaws, yields faster and smoother degeneration recovery and extends the range of well‐behaved degenerate configurations without adding significant complexity or computational cost to standard explicit and quasi‐implicit solvers. 相似文献
50.
挡水结构水下爆炸作用的离心模型试验 总被引:1,自引:0,他引:1
水下爆炸包括冲击波和气泡脉动,两者能量相当,均会对结构产生毁伤作用。水下爆炸载荷试验唯有在离心机内才满足相似关系,设计试验时宜在离心机负载范围内尽可能增加模型尺寸以减小边界效应。针对挡水结构,在离心机内布置压力传感器、高速摄像机、加速度计及应变片测试了冲击波、气泡脉动载荷及结构产生的动力响应。通过试验对比了水下爆炸和空爆产生的载荷,分析其引起结构动力响应的差异。对于水下爆炸,重力加速度的增加引起气泡脉动冲量的减小,而气泡脉动产生的峰值应变基本与气泡冲量呈线性关系,因而模拟气泡脉动对结构作用时应考虑重力效应。 相似文献