全文获取类型
收费全文 | 327篇 |
免费 | 47篇 |
国内免费 | 21篇 |
专业分类
电工技术 | 11篇 |
综合类 | 31篇 |
化学工业 | 16篇 |
金属工艺 | 1篇 |
机械仪表 | 14篇 |
建筑科学 | 4篇 |
矿业工程 | 4篇 |
能源动力 | 6篇 |
轻工业 | 5篇 |
水利工程 | 5篇 |
石油天然气 | 35篇 |
武器工业 | 3篇 |
无线电 | 108篇 |
一般工业技术 | 32篇 |
冶金工业 | 18篇 |
原子能技术 | 3篇 |
自动化技术 | 99篇 |
出版年
2024年 | 2篇 |
2023年 | 5篇 |
2022年 | 12篇 |
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 8篇 |
2018年 | 7篇 |
2017年 | 14篇 |
2016年 | 17篇 |
2015年 | 22篇 |
2014年 | 17篇 |
2013年 | 24篇 |
2012年 | 23篇 |
2011年 | 25篇 |
2010年 | 19篇 |
2009年 | 17篇 |
2008年 | 22篇 |
2007年 | 26篇 |
2006年 | 22篇 |
2005年 | 19篇 |
2004年 | 18篇 |
2003年 | 11篇 |
2002年 | 4篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 7篇 |
1998年 | 2篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1974年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有395条查询结果,搜索用时 31 毫秒
1.
2.
论反射地震偏移成像 总被引:53,自引:14,他引:39
马在田 《勘探地球物理进展》2002,25(3):1-5
对反射地震偏移成像问题进行了分析、对比与探讨,并对各种偏移方法如叠后时间偏移、叠后深度偏移、叠前时间偏移、叠前深度偏移和它们之间在地质效果上的异同进行了讨论。认为,在当前的地面观测记录的质量条件下,叠后时间偏移和叠后深度偏移,叠前时间偏移和叠前深度偏移,都有各自的优势和不足。因此,它们都有应用价值,不是互相排斥,而是互相补充。今后的方向是发展和完善高分辨率和高保真度的偏移成像方法。在这方面还有许多问题要解决。 相似文献
3.
Two studies explored how domestic violence may be implicitly or explicitly sanctioned and reinforced in cultures where honor is a salient organizing theme. Three general predictions were supported: (a) female infidelity damages a man's reputation, particularly in honor cultures; (b) this reputation can be partially restored through the use of violence; and (c) women in honor cultures are expected to remain loyal in the face of jealousy-related violence. Study 1 involved participants from Brazil (an honor culture) and the United States responding to written vignettes involving infidelity and violence in response to infidelity. Study 2 involved southern Anglo, Latino, and northern Anglo participants witnessing a "live" incident of aggression against a woman (actually a confederate) and subsequently interacting with her. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
This study aimed at identifying the roll motion parameters of a motorcycle simulator prototype. Experienced motorcyclists tuned the angular physical movement of the mock-up and that of the visual scene to achieve an optimal riding experience during curves. The participants exceeded the rolling angles that would be required in real-world riding, while avoiding leaning the mock-up beyond 10°. In addition, they were more influenced by the speed of the virtual motorcycle than by road curvature, especially in a wide field of view. Heterogeneity was found in the roll applied to the visual scene. The overall patterns suggest that at least when washout is not applied to remove the side forces that in real-world riding are compensated by a centrifugal force, greater roll of the visual at the expense of the mock-up is mandatory to avoid performance biases that might be enhanced due to fear of falling off the simulator. Future roll motion models must take into consideration factors such as riding postures, which might not only influence the forces operating on the rider-motorcycle system, but also how motorcyclists perceive the visual world. 相似文献
5.
CAD模型造型精度高 ,渲染效果逼真 ,被广泛应用于虚拟现实、实时仿真以及三维地理信息系统等三维可视化中 ,但是其几何模型数据复杂 ,图像数据量大 ,也导致可视化效率低下。为此 ,提出了一种 CAD模型数据重组织方法 ,旨在解决当前可视化应用集成 CAD模型数据效率低下的问题。采用预先计算可视化信息 ,高度紧凑组织数据 ,顾及图形软硬件特性等一系列策略 ,实现 CAD模型数据的高效可视化功能。其中 ,几何模型绘制和图像纹理生成效率均提高了 10倍以上。该方法被成功应用于香港志莲净苑佛寺虚拟旅游演示项目中。 相似文献
6.
Mark A. Kaemingk Tracy L. Galarowicz John A. Clevenger David F. Clapp 《Journal of Great Lakes research》2011,37(4):625-631
Fish movement may vary across a wide array of aquatic ecosystems and may be related to the overall size of the system inhabited. We investigated movement of smallmouth bass in Lake Michigan because this information is lacking for larger systems. A total of 16 smallmouth bass were surgically implanted with ultrasonic transmitters within the Beaver Archipelago, northern Lake Michigan. During 2007-2008, a maximum of one location per individual was recorded daily during three specific tracking periods - pre-spawn, spawning, and post-spawn - to determine diurnal movement patterns. Movement was evaluated as site fidelity, minimum displacement rate, maximum excursion rate, and distance from shore. Smallmouth bass exhibited greater maximum excursion rates during the spawn period compared to pre-spawn. Movement rates did not differ between tracking periods; however, movement rates were greater during the spawn period in 2007 than 2008. Both sexes moved further offshore to deeper water during post-spawn, but females were located further offshore than males during this period. Annual site fidelity was more evident during post-spawn than during spawning for both sexes. Two smallmouth bass emigrated outside of the Archipelago, suggesting this population may be more “open” in terms of individuals moving throughout northern Lake Michigan than previously thought. These results indicate smallmouth bass may move greater distances in larger aquatic systems and therefore larger management units (in terms of total area) should be established in Lake Michigan to account for these greater excursion distances. 相似文献
7.
8.
网络多媒体的迅猛发展和普及使得对海量视频信息进行快速和低成本管理的需求日益迫切,而关键帧可以大大减少视频索引的数据量,同时也为查询和检索视频提供了一个组织框架。针对现有关键帧提取算法存在的特征选取单一、阈值选择困难和视频类型局限性等问题,提出了一种基于多特征相似度曲线最大曲率点检测的关键帧提取方法。算法利用多特征融合的相似性度量来捕获视频内容的显著变化,弥补了单一特征对视频内容描述不充分的不足,且基于滑动窗口的检测算法无需阈值选择,可以实时、局部地提取关键帧,解决了传统算法计算量大、通用性差的问题。最后通过实验利用一种保真度评估标准验证了该算法的有效性。 相似文献
9.
An empirical study examined the impact of user expertise and prototype fidelity on the outcomes of a usability test. User expertise (expert vs. novice) and prototype fidelity (paper prototype, 3D mock-up, and fully operational appliance) were manipulated as independent variables in a 2 × 3 between-subjects design. Employing a floor scrubber as a model product, 48 users carried out several cleaning tasks. Usability problems identified by participants were recorded. Furthermore, performance, system management strategies and perceived usability were measured. The results showed that experts reported more usability problems than novices but these were considered to be less severe than those reported by novices. Reduced fidelity prototypes were generally suitable to predict product usability of the real appliance. The implications for the running of usability tests are specific to the fidelity of the prototype. 相似文献
10.
An empirical study examined the impact of prototype fidelity on user behaviour, subjective user evaluation and emotion. The independent factors of prototype fidelity (paper prototype, computer prototype, fully operational appliance) and aesthetics of design (high vs. moderate) were varied in a between-subjects design. The 60 participants of the experiment were asked to complete two typical tasks of mobile phone usage: sending a text message and suppressing a phone number. Both performance data and a number of subjective measures were recorded. The results suggested that task completion time may be overestimated when a computer prototype is being used. Furthermore, users appeared to compensate for deficiencies in aesthetic design by overrating the aesthetic qualities of reduced fidelity prototypes. Finally, user emotions were more positively affected by the operation of the more attractive mobile phone than by the less appealing one. 相似文献