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   817篇
  免费   74篇
  国内免费   64篇
电工技术   13篇
综合类   41篇
化学工业   13篇
金属工艺   17篇
机械仪表   71篇
建筑科学   88篇
矿业工程   17篇
能源动力   13篇
轻工业   6篇
水利工程   6篇
石油天然气   8篇
武器工业   3篇
无线电   106篇
一般工业技术   24篇
冶金工业   21篇
原子能技术   5篇
自动化技术   503篇
  2024年   2篇
  2023年   16篇
  2022年   20篇
  2021年   21篇
  2020年   15篇
  2019年   18篇
  2018年   20篇
  2017年   15篇
  2016年   16篇
  2015年   26篇
  2014年   49篇
  2013年   43篇
  2012年   50篇
  2011年   74篇
  2010年   50篇
  2009年   43篇
  2008年   54篇
  2007年   64篇
  2006年   56篇
  2005年   39篇
  2004年   38篇
  2003年   40篇
  2002年   33篇
  2001年   29篇
  2000年   17篇
  1999年   15篇
  1998年   13篇
  1997年   9篇
  1996年   11篇
  1995年   7篇
  1994年   5篇
  1993年   5篇
  1992年   5篇
  1991年   9篇
  1990年   1篇
  1989年   3篇
  1988年   4篇
  1987年   1篇
  1986年   3篇
  1985年   1篇
  1983年   1篇
  1982年   3篇
  1981年   1篇
  1980年   3篇
  1978年   2篇
  1976年   5篇
排序方式: 共有955条查询结果,搜索用时 31 毫秒
51.
Localizing an epileptic network is essential for guiding neurosurgery and antiepileptic medical devices as well as elucidating mechanisms that may explain seizure-generation and epilepsy. There is increasing evidence that pathological oscillations may be specific to diseased networks in patients with epilepsy and that these oscillations may be a key biomarker for generating and indentifying epileptic networks. We present a semi-automated method that detects, maps, and mines pathological gamma (30-100 Hz) oscillations (PGOs) in human epileptic brain to possibly localize epileptic networks. We apply the method to standard clinical iEEG (<100 Hz) with interictal PGOs and seizures from six patients with medically refractory epilepsy. We demonstrate that electrodes with consistent PGO discharges do not always coincide with clinically determined seizure onset zone (SOZ) electrodes but at times PGO-dense electrodes include secondary seizure-areas (SS) or even areas without seizures (NS). In 4/5 patients with epilepsy surgery, we observe poor (Engel Class 4) postsurgical outcomes and identify more PGO-activity in SS or NS than in SOZ. Additional studies are needed to further clarify the role of PGOs in epileptic brain.  相似文献   
52.
Daodi Flood Land, located in Mentougou District of Beijing, is a relatively separate flood land in the lower reaches and on the east of Yonding River. This largest landscape character area in the west of Beijing along the river illustrates the history of human–water interaction and discloses the trends and problems of rural urbanization. Focusing on Daodi Flood Land, this paper expands the research on adaptation by introducing basic concepts and research framework, and reviews the research trends from spatial, temporal, and participant aspects. Considering the typical characters of the study area, this research employed participatory approaches, such as mapping and problem and solution trees, due to the lack of continuous and accurate data. Basing on literature review and field investigation on issues of floods, agricultural irrigation, and water resource utilization, water adaptive development visions for the study area were proposed from perspectives of landscape and culture. Finally, the paper further analyzes the structural relations between adaptation problems, natural and social systems, passive and active adaptations, and planned and unplanned adaptations, with the aim to provide reference for relevant studies and applications of adaptation approaches in other cases.  相似文献   
53.
Non-communicable diseases burden is well-known and care for these diseases goes beyond patients’ engagement, extending to their family, friends, and acquaintances. The ability of social relations in alleviating the harmful effects of health risks is known as social support. Computing can be used to promote social support to enhance the care of non-communicable diseases. However, it is unclear how computing obtains such enhancement. This paper presents a systematic review, in the form of a mapping study, aiming to answer how computing enhances non-communicable diseases care by using social data and by promoting social support. It also looks for available computing models focused on social support promotion in non-communicable diseases care. The study was guided by a two-phase process review, resulting in 38 reviewed papers from journals, conferences, and chapters in the period from 2010 to 2016. In general, the reviewed papers focus on controlled trials, frameworks and systems, knowledge discovery, simulation models or social media usage analysis. Knowledge discovery was the predominant subject, followed by social media usage analysis, and frameworks and systems.  相似文献   
54.
The geometry of cutting flutes and the surfaces of end mills is one of the crucial parameters affecting the quality of the machining in the case of end milling. These are usually represented by two-dimensional models. This paper describes in detail the methodology to model the geometry of a flat end mill in terms of three-dimensional parameters. The geometric definition of the end mill is developed in terms of surface patches; flutes as helicoidal surfaces, the shank as a surface of revolution and the blending surfaces as bicubic Bezier and biparametric sweep surfaces. The proposed model defines the end mill in terms of three-dimensional rotational angles rather than the conventional two dimensional angles. To validate the methodology, the flat end milling cutter is directly rendered in OpenGL environment in terms of three-dimensional parameters. Further, an interface is developed that directly pulls the proposed three-dimensional model defined with the help of parametric equations into a commercial CAD modeling environment. This facilitates a wide range of downstream technological applications. The modeled tool is used for finite element simulations to study the cutting flutes under static and transient dynamic load conditions. The results of stress distribution (von mises stress), translational displacement and deformation are presented for static and transient dynamic analysis for the end mill cutter flute and its body. The method described in this paper offers a simple and intuitive way of generating high-quality end mill models for use in machining process simulations. It can be easily extended to generate other tools without relying on analytical or numerical formulations.  相似文献   
55.
Geophysical surveys could contribute significantly to remediation programs for damaged buried engineering structures. Resistivity profiling and mapping techniques used in this work allow rapid and one of the most cost-effective ways of characterization and visualization of internal defects of drainage and watering systems of football playgrounds in a nondestructive way. Cost-effective and nondestructive testing can be valuable assets for diagnosis, realization, and restoration of football playgrounds.  相似文献   
56.
由于各种因素的影响,地形图会发生不规则变形,因此,必须对其进行纠正.为此提出了一种射影变换纠正法,叙述了其纠正方法和纠正原理,并总结了其优点.  相似文献   
57.
李凌敏  侯梦然  陈琨  刘军民 《计算机应用》2022,42(12):3639-3650
近年来,深度学习在很多领域得到广泛应用;然而,由于深度神经网络模型的高度非线性操作,导致其可解释性较差,并常常被称为“黑箱”模型,无法应用于一些对性能要求较高的关键领域;因此,对深度学习的可解释性开展研究是很有必要的。首先,简单介绍了深度学习;然后,围绕深度学习的可解释性,从隐层可视化、类激活映射(CAM)、敏感性分析、频率原理、鲁棒性扰动测试、信息论、可解释模块和优化方法这8个方面对现有研究工作进行分析;同时,展示了深度学习在网络安全、推荐系统、医疗和社交网络领域的应用;最后,讨论了深度学习可解释性研究存在的问题及未来的发展方向。  相似文献   
58.
针对键盘电磁信息安全问题,分析了PS/2键盘的工作原理以及信号特征,提出一种基于深度学习的检测方法。该方法针对键盘设备的电磁泄漏信号特征,对卷积神经网络(CNN)结构进行了适应性调整;结合改进的梯度加权类激活映射方法,实现了对键盘电磁信息的智能识别和精准定位。对4个按键的电磁信号进行测试,分类准确率达到了98%;在噪声环境下的分类准确率也达到了81%。将梯度加权类激活映射方法及其改进方法对键盘电磁信息的定位效果进行了对比,实验结果证明改进后的方法定位效果更佳。  相似文献   
59.
利用LIDAR技术进行江苏沿海滩涂地区测绘是国内首次利用LIDAR进行沿海滩涂、海岛礁高精度、高分辨率测绘,该项目综合运用精确大地水准面成果、连续运行参考站卫星定位综合服务系统以及数字计算机处理技术制作DEM、DOM、DLG等产品.在分析江苏沿海滩涂特点的基础上,介绍了该项目的实施过程、特点及关键技术.  相似文献   
60.
 本文基于EJB3.0技术设计实现了煤矿分布式空间数据库同步系统,并结合LRGIS 3.0以地测部门的采掘工程平面图为例加以阐述,保障了煤矿空间数据的一致性、时效性,结合LRGIS 3.0实现了矿山信息化管理。  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