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   8344篇
  免费   1623篇
  国内免费   1054篇
电工技术   488篇
技术理论   1篇
综合类   1116篇
化学工业   124篇
金属工艺   95篇
机械仪表   594篇
建筑科学   182篇
矿业工程   80篇
能源动力   41篇
轻工业   94篇
水利工程   79篇
石油天然气   68篇
武器工业   95篇
无线电   1313篇
一般工业技术   447篇
冶金工业   461篇
原子能技术   37篇
自动化技术   5706篇
  2024年   32篇
  2023年   245篇
  2022年   365篇
  2021年   359篇
  2020年   294篇
  2019年   237篇
  2018年   172篇
  2017年   232篇
  2016年   248篇
  2015年   261篇
  2014年   383篇
  2013年   357篇
  2012年   484篇
  2011年   572篇
  2010年   480篇
  2009年   463篇
  2008年   584篇
  2007年   688篇
  2006年   616篇
  2005年   575篇
  2004年   517篇
  2003年   502篇
  2002年   491篇
  2001年   418篇
  2000年   353篇
  1999年   235篇
  1998年   191篇
  1997年   148篇
  1996年   95篇
  1995年   72篇
  1994年   88篇
  1993年   50篇
  1992年   29篇
  1991年   33篇
  1990年   25篇
  1989年   16篇
  1988年   24篇
  1987年   7篇
  1986年   12篇
  1985年   11篇
  1984年   15篇
  1983年   4篇
  1982年   4篇
  1980年   3篇
  1979年   3篇
  1964年   3篇
  1963年   2篇
  1959年   2篇
  1957年   2篇
  1956年   2篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Relatively recently it has become apparent that providing human kind with a better healthcare requires personalized, predictive and integrative medicine, for which the building of virtual physiological human (VPH) framework accessible via virtual patient avatar is necessary. Real‐time modelling and visual exploration of such a complex avatar is a challenging task. In this paper, we propose a real‐time method for automatic modelling of an arbitrarily large number of muscle fibres in the volume of a muscle represented by its surface mesh. The method is based on an iterative morphing of predefined fibres template into the muscle volume exploiting harmonic scalar field computed on the surface of muscle. Experiments with muscles of thighs and pelvis show that the method produces realistic shapes of fibres. Our sequential VTK‐based C++ implementation is capable of producing 64 fine fibres within a muscle of 10K triangles in less than 170 ms on commodity hardware making the method suitable for VPH purposes as well as for interactive educational medical software.  相似文献   
102.
The article deals with the experimental studies of atmosphere indistinct radiation structure. The information extraction background of dot size thermal object presence in atmosphere is reasonable. Indistinct generalization of experimental study regularities technique of space-time irregularity radiation structure in infrared wave range is offered. The approach to dot size thermal object detection in atmosphere is proved with a help of threshold method in the thermodynamic and turbulent process conditions, based on the indistinct statement return task solution.  相似文献   
103.
Ultrasound velocity profiling was applied to viscoelastic flow induced around a moving permeable disk. There were two objectives to this measurement. The first was to find technical advantages and restrictions when applying ultrasonic Doppler velocimetry to a viscoelastic liquid. This issue has not been clarified even though ultrasonic pulses may interact with an elastic medium in the monitoring of the Doppler shift frequency. The second objective was to determine the fluid physics of a viscoelastic liquid around a permeable object, which will help in designing mixing process for materials subject to strong rheological resistance. In this paper, we report a representative response of a viscoelastic liquid in terms of its spatiotemporal velocity distribution. The response highlighted is cyclic lateral waves that form behind the disk, which were hardly detectable by particle image velocimetry. We discuss multiple reasons for this phenomenon considering not only fluid properties but also the measurement principle of ultrasound velocity profiling as applied to viscoelastic liquid.  相似文献   
104.
This research proposes that it is possible to deliberately reduce temporal tensions in order to promote energy saving behaviours. People may not dedicate enough time to planning their tasks that consume energy, rushing into them without much deliberation. They may also use more energy than necessary in an attempt to accelerate processes that seem to be taking too long, to reduce the boredom of waiting. Persuasive technology provided the tools to manipulate the perception of time and therefore elicit changes in the specific behaviours that result in unnecessary energy usage. Cooking tasks were used as the scenario to test behaviour change strategies delivered via a smartphone application. Results showed that these strategies facilitated the performance of sustainable behaviours. Participants reported that the app made (1) them more likely to follow the steps needed to use less energy, (2) the activity more enjoyable and (3) the time appear to pass more quickly compared to a control version.  相似文献   
105.
Minimizing the spread of infections is a challenging problem, and it is the subject matter in many different fields such as epidemiology and cyber-security. In this paper, we investigate link removal as an intervention strategy and study the relative effectiveness of different link removal methods in minimizing the spread of infections in a network. With that in mind, we develop four connectivity-based network interdiction models and formulate these models as mixed integer linear programs. The first model minimizes the number of connections between infected and susceptible nodes; the second the number of susceptible nodes having one or more connections with infected nodes; the third the total number of paths between infected and susceptible nodes; and the fourth the total weight of the paths between infected and susceptible nodes. We also propose heuristic algorithms to solve the models. The network interdiction models act as link removal methods, i.e., each return a solution consisting of a set of links to remove in the network. We compare the effectiveness of these four methods with the effectiveness of an existing link removal method [25], a method based on link betweenness centrality [18], and random link removal method. Our results show that complete isolation of susceptible nodes from infected nodes is the most effective method in reducing the average number of new infections (reduce occurrence) under most scenarios, and the relative effectiveness of the complete isolation method increases with transmission probability. In contrast, removing the highest probability transmission paths is the most effective method in increasing the average time to infect half of the susceptible nodes (reduce speed) under most scenarios, and the relative effectiveness of this method decreases with transmission probability.  相似文献   
106.
Some approximate indexing schemes have been recently proposed in metric spaces which sort the objects in the database according to pseudo-scores. It is known that (1) some of them provide a very good trade-off between response time and accuracy, and (2) probability-based pseudo-scores can provide an optimal trade-off in range queries if the probabilities are correctly estimated. Based on these facts, we propose a probabilistic enhancement scheme which can be applied to any pseudo-score based scheme. Our scheme computes probability-based pseudo-scores using pseudo-scores obtained from a pseudo-score based scheme. In order to estimate the probability-based pseudo-scores, we use the object-specific parameters in logistic regression and learn the parameters using MAP (Maximum a Posteriori) estimation and the empirical Bayes method. We also propose a technique which speeds up learning the parameters using pseudo-scores. We applied our scheme to the two state-of-the-art schemes: the standard pivot-based scheme and the permutation-based scheme, and evaluated them using various kinds of datasets from the Metric Space Library. The results showed that our scheme outperformed the conventional schemes, with regard to both the number of distance computations and the CPU time, in all the datasets.  相似文献   
107.
Mechanical parts, plants, and cross‐linkages inspected with magnetic‐particle testing (MT) are typically complex 3D shapes. In complex 3D shape portions, because a magnetizer often cannot be configured to inspection portions and the test object cannot be appropriately magnetized, there is a possibility of overlooking a crack in such an instance. Thus, MT system development that was successfully able to detect omnidirectional cracks in 3D shape portions was considered in this study's trials. Two multi‐coil type magnetizers were hence arranged face‐to‐face, and the magnetization of omnidirectional scenarios for all surfaces of 3D shape test object was evaluated.  相似文献   
108.
Augmented reality (AR) by a projector allows for the easy association of information by labeling the objects. When a projector is installed above a workspace and pointed downward, supportive information can be presented; however, the label will be deformed if the object is nonplanar. Also, a label might be projected in a region where it is hidden by the object, i.e., a blind area. In this paper, we propose a view management technique to allow interpretation by improving the legibility of the information. We propose the nonoverlapped gradient descent (NGD) method, which determines the position of a newly added label by avoiding overlap with the surrounding labels and linkage lines. The issues of presenting in a shadow or blind area are also addressed by estimating these areas based on the approximation of objects as a simple solid. The results of an experiment show that the visibility of the labels was improved by using this method.  相似文献   
109.
提出了根据约束进行协调作业的位姿、速度的对应与分解的关系从而实现双工业机器人协调作业的方法.通过对机器人运动学的分析、双工业机器人安装位姿以及协调作业的运动约束的分析与描述,确定双工业机器人运动学关系.通过对机器人关节角的改变控制双工业机器人工具坐标系原点.以螺旋副的拆装为例从运动学的角度实现了双工业机器人的协调作业.研究证明,利用该方法能够实现双工业机器人的协调作业.  相似文献   
110.
介绍了双客水箱液位控制系统的组成及工作原理.以单片机为核心,利用ADC0809和ADC0832实现了工业现场和单片机之问进行信息交换的输入输出通道,完成了模拟信号和数字信号之间的转换,利用LCD和键盘完成人机交互对话,设计出了运行效果良好的直接数字液位控制系统.  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