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   1226篇
  免费   53篇
  国内免费   17篇
电工技术   9篇
综合类   84篇
化学工业   79篇
金属工艺   51篇
机械仪表   38篇
建筑科学   68篇
矿业工程   109篇
能源动力   17篇
轻工业   25篇
水利工程   10篇
石油天然气   475篇
武器工业   20篇
无线电   35篇
一般工业技术   30篇
冶金工业   38篇
原子能技术   3篇
自动化技术   205篇
  2024年   1篇
  2023年   11篇
  2022年   18篇
  2021年   31篇
  2020年   41篇
  2019年   31篇
  2018年   32篇
  2017年   22篇
  2016年   44篇
  2015年   49篇
  2014年   54篇
  2013年   43篇
  2012年   63篇
  2011年   65篇
  2010年   61篇
  2009年   56篇
  2008年   61篇
  2007年   48篇
  2006年   48篇
  2005年   61篇
  2004年   55篇
  2003年   44篇
  2002年   38篇
  2001年   46篇
  2000年   47篇
  1999年   47篇
  1998年   45篇
  1997年   34篇
  1996年   35篇
  1995年   28篇
  1994年   5篇
  1993年   4篇
  1992年   8篇
  1991年   4篇
  1990年   4篇
  1988年   1篇
  1987年   1篇
  1986年   3篇
  1985年   2篇
  1981年   2篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
排序方式: 共有1296条查询结果,搜索用时 15 毫秒
31.
This paper describes an object rearrangement system for an autonomous mobile robot. The objective of the robot is to autonomously explore and learn about an environment, to detect changes in the environment on a later visit after object disturbances and finally, to move objects back to their original positions. In the implementation, it is assumed that the robot does not have any prior knowledge of the environment and the positions of the objects. The system exploits Simultaneous Localisation and Mapping (SLAM) and autonomous exploration techniques to achieve the task. These techniques allow the robot to perform localisation and mapping which is required to perform the object rearrangement task autonomously. The system includes an arrangement change detector, object tracking and map update that work with a Polar Scan Match (PSM) Extended Kalman Filter (EKF) SLAM system. In addition, a path planning technique for dragging and pushing an object is also presented in this paper. Experimental results of the integrated approach are shown to demonstrate that the proposed approach provides real-time autonomous object rearrangements by a mobile robot in an initially unknown real environment. Experiments also show the limits of the system by investigating failure modes.  相似文献   
32.
The sensitivity of guided mode resonance filter (GMRF) biosensors was analyzed when the initial peak wavelength (IPW) changed from 400 to 1600 nm. The sensitivity of the GMRF to the sample refractive index and thickness was analyzed using rigorous coupled wave analysis method. Results indicate that for a certain IPW, the sensitivity of the GMRF did not change when the sample refractive index varied, but drastically decreased and achieved constant sensitivity with increased sample thickness. When the IPW increased, the sensitivity improved in relation to both sample refractive index and sample thickness. Furthermore, the capability of sample thickness improved with longer IPW. These results are helpful in obtaining an optimal GMRF biosensor.  相似文献   
33.
针对彩色扫描地形图中线要素与背景要素难以分离,现有线要素提取算法提取的结果中存在边界不准确的问题,提出基于Guided Filter的地形图中线要素提取算法。利用基于能量密度和Shear变换相结合的线要素提取算法对线要素进行粗提取;引入Guided Filter,以源地形图图像作为Guided Filter的引导图像,以粗提取的线要素图像作为Guided Filter的输入图像,经过滤波处理获得的线要素信息更为显著;利用OTSU算法得到最终的线要素信息。实验结果表明:相对于现有的线要素提取算法,提出的算法能够更为准确地提取出地形图中的线要素,并具有更好的噪声抑制能力。  相似文献   
34.
Future multimedia applications such as full HD (1920 × 1080) multiview video coding (MVC) present great challenges on computing architectures. Even if with the state-of-the-art ASIC technology which can process single view HD decoding, dealing with multiple views would require times of computation capacity in proportion to the number of views, which is difficult to achieve. In this paper, we explore the system-level design space for full HD MVC applications mapped onto mesh-based multicore Network-on-Chip (NoC) architectures. To this end, we establish a simulation framework capable of simulating the combination of communication networks with computing cores. We investigate two task assignment schemes: picture-level assignment and view-level assignment. With an eight-view MVC decoding, we explore the design options with respect to network size, single-core performance and link bandwidth under both task assignment schemes. Our studies show that, to achieve a certain decoding performance, the computation capability and communication capacity should be balanced in the system. Also, to realize the eight-view HD decoding, the system only requires twice or less than twice of the single-core processing capacity required by single view decoding, thanks to the parallel computation and communication enabled by the multicore NoC architectures. Our results exhibit feasibility and potential of efficiently implementing the full HD MVC decoding on multicore NoC architectures.  相似文献   
35.
GIS在油气勘探数据管理中的应用研究*   总被引:1,自引:0,他引:1  
油气勘探数据与地理信息密切相关,数据量大、类型复杂,传统的数据管理方法已经不适应现代管理的要求。利用地理信息系统(GIS)技术,通过建立图形库和属性库存储和管理大量与油气勘探相关的勘探数据和图形信息,并能进行有关的分析,建立油气勘探数据管理系统,可为勘探工作的管理提供先进的手段,为进一步的勘探部署和决策提供科学可靠的依据。在介绍了VC++环境下MAPGIS二次开发方法的基础上,对开发中的关键技术进行了探讨,并介绍了基于GIS技术的油气勘探数据管理系统的主要功能。  相似文献   
36.
在VC++6.0中实现对3D Max构造OpenGL模型的控制   总被引:6,自引:0,他引:6  
首先用3D Max进行实体建模,然后在VC++中对这一模型进行实时调用,从而实现了对实体的实时控制。  相似文献   
37.
This article explores the strategies used by Israeli students to resolve the Israeli-Palestinian conflict in the interactive computer game, PeaceMaker. Students played PeaceMaker in the roles of both the Israeli Prime Minister and the Palestinian President in random order. Students must take actions satisfying constituents on both sides of the conflict in order to win the game. The diversity of actions taken in each role was measured. Several hypotheses test the degree to which Israeli students, depending on which role they played and their own demographic variables, exploited a consistent set of actions or explored a more diverse range of actions across three main types: construction, political, and security. The results show that (1) greater action diversity increases success in both roles, (2) Israeli students engaged in less diverse actions when playing the Israeli role than when playing the Palestinian role, (3) students’ religiosity and political Hawkishness negatively predicted action diversity when playing the Palestinian role, and (4) action diversity mediates the relationship between a student’s background knowledge about the conflict and success in the Israeli role. The significance of these findings for understanding attitudes about the Israeli-Palestinian conflict are discussed, including implications for conflict resolution more generally.  相似文献   
38.
作为机械类专业中的一门实践类课程,UG课程的教学效果不够理想,主要原因在于其知识点中的重点难点较多,学生对其理解不够透彻,以及教材的工程实用性不够强.而微课,作为一种新型的教学形式,对于改善UG课程的教学效果有着重要的作用.在具体的UG课程的微课设计中,教师应注重微课内容的选取、微课导入环节及教学过程的设计以及微课教学视频的展示效果,充分发挥微课在UG课程中的教学补充和延伸作用.  相似文献   
39.
依据六盘山盆地露头和钻测井资料,应用有机地球化学的多种分析方法,对六盘山盆地乃家河—马东山烃源岩进行分析评价,分析表明:乃家河组烃源岩有机含量为0.43%~3.18%,平均值为1.76%,有机质类型以偏腐泥为主,镜质体反射率Ro值为0.52%~0.67%,平均值为0.60%,马东山烃源岩有机质含量为0.73%~3.65%平均值为1.69%,有机质类型以偏腐植型为主,晶质体反射率Ro为0.64%~0.75%,平均值为0.69%.对比可知,马东山组烃源岩的有机质丰富,热演化程度好于乃家河组,但同质类型没有乃家河组好.六盘山具有两套生储组合,白垩系李洼峡组发现不同级别油气显示,有较好的油气成藏条件,油气资源丰富,勘探潜力较好.  相似文献   
40.
长期以来,江陵凹陷油气勘探以深层新沟嘴组和白垩系为重点,对荆沙组地层未作系统分析与评价,其基本成藏条件研究不深入,勘探潜力不明确。近期沙26-8井在荆沙组的钻探取得重大突破,明确荆沙组具有一定的成藏条件,使得荆沙组成为研究重点和储量增长新的勘探目的层。  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