全文获取类型
收费全文 | 11586篇 |
免费 | 1190篇 |
国内免费 | 693篇 |
专业分类
电工技术 | 497篇 |
技术理论 | 1篇 |
综合类 | 1079篇 |
化学工业 | 705篇 |
金属工艺 | 306篇 |
机械仪表 | 701篇 |
建筑科学 | 1086篇 |
矿业工程 | 653篇 |
能源动力 | 538篇 |
轻工业 | 760篇 |
水利工程 | 374篇 |
石油天然气 | 232篇 |
武器工业 | 106篇 |
无线电 | 1172篇 |
一般工业技术 | 2134篇 |
冶金工业 | 1487篇 |
原子能技术 | 177篇 |
自动化技术 | 1461篇 |
出版年
2024年 | 70篇 |
2023年 | 183篇 |
2022年 | 311篇 |
2021年 | 404篇 |
2020年 | 410篇 |
2019年 | 352篇 |
2018年 | 312篇 |
2017年 | 348篇 |
2016年 | 452篇 |
2015年 | 413篇 |
2014年 | 613篇 |
2013年 | 703篇 |
2012年 | 745篇 |
2011年 | 886篇 |
2010年 | 689篇 |
2009年 | 748篇 |
2008年 | 652篇 |
2007年 | 722篇 |
2006年 | 687篇 |
2005年 | 553篇 |
2004年 | 470篇 |
2003年 | 417篇 |
2002年 | 352篇 |
2001年 | 358篇 |
2000年 | 230篇 |
1999年 | 193篇 |
1998年 | 192篇 |
1997年 | 144篇 |
1996年 | 128篇 |
1995年 | 99篇 |
1994年 | 84篇 |
1993年 | 63篇 |
1992年 | 58篇 |
1991年 | 31篇 |
1990年 | 36篇 |
1989年 | 31篇 |
1988年 | 25篇 |
1987年 | 23篇 |
1985年 | 15篇 |
1984年 | 14篇 |
1983年 | 11篇 |
1981年 | 13篇 |
1964年 | 23篇 |
1963年 | 21篇 |
1961年 | 13篇 |
1960年 | 17篇 |
1959年 | 19篇 |
1958年 | 10篇 |
1957年 | 15篇 |
1955年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
101.
102.
针对传统电力变压器绝缘油位测量的局限性,提出一种压力式光纤液位传感器的变压器绝缘油位监测系统.系统采用压力式光纤液位传感器作为绝缘油位的传感器件,该传感器对光源强度变化、光纤传输过程中的光功率损耗具有光强起伏补偿功能;以数字信号处理器TMS320F2812为处理和控制核心,实现对变压器油位的无人实时在线监测.分析了油位... 相似文献
103.
高灵敏度金属分离器传感线圈的设计 总被引:1,自引:0,他引:1
分析了电感线圈探测金属的理论,针对传统的金属探测传感器灵敏度低,抗干扰能力差和结构复杂的缺点,根据电磁感应原理提出了一种具有高探测精度和高抗干扰能力的新型金属探测传感器,并描述了其结构和材料设计方案。最后用试验验证了设计思想和设计方案的正确性和实用性。 相似文献
104.
差动吸收式SO2光纤传感器的研究 总被引:4,自引:0,他引:4
本文基于气体的窄带光吸收特性 ,研究了 SO2 气体浓度与载波光强的关系 ,在此基础上 ,设计了一种检测该气体浓度的差动光纤传感器及其系统 ,对改善仪器精度等特性指标的主要因素进行分析。实验结果表明该仪器具有较高的灵敏度和精度。 相似文献
105.
Structured Reactive Controllers 总被引:1,自引:0,他引:1
Michael Beetz 《Autonomous Agents and Multi-Agent Systems》2001,4(1-2):25-55
Service robots, such as autonomous office couriers or robot tourguides, must be both reliable and efficient. This requires them to flexibly interleave their tasks, exploit opportunities, quickly plan their course of action, and, if necessary, revise their intended activities. In this paper, we show how structured reactive controllers (SRCs) satisfy these requirements. The novel feature of SRCs is that they employ and reason about plans that specify and synchronize concurrent percept-driven behavior. Powerful control abstractions enable SRCs to integrate physical action, perception, planning, and communication in a uniform framework and to apply fast but imperfect computational methods without sacrificing reliability and flexibility. Concurrent plans are represented in a transparent and modular form so that automatic planning processes can reason about the plans and revise them. We present experiments in which SRCs are used to control two autonomous mobile robots. In one of them an SRC controlled the course of action of a museum tourguide robot that has operated for thirteen days, more than ninetyfour hours, completed 620 tours, and presented 2668 exhibits. 相似文献
106.
107.
108.
基于知觉加工模式的发展式分词算法 总被引:2,自引:0,他引:2
危辉 《计算机研究与发展》2001,38(11):1281-1289
分词是自然语言理解的一个重要过程,由于语言问题又是最重要的心理学问题之一,所以从认知心理学和发展心理学的观点出发,将分词问题看成是知觉问题在语言信息处理过程中的一部分,把知觉表达和知觉的双向加工过程引入对分词问题的分析,并同时考虑言语发展的心理过程,把对言语发展规律的归纳作为构造学习算法的基础和模板,以进化的方式来逐步改进自然语言理解系统的性能,从而避免知识获取瓶颈在自然语言理解问题中的出现。 相似文献
109.
《Ergonomics》2012,55(9):1273-1282
AbstractThis study clarifies the associations between accident history, perception of the riskiness of road travel and traffic safety behaviours by taking into account the number and severity of accidents experienced. A sample of 525 road users in Cameroon answered a questionnaire comprising items on perception of risk, safe behaviour and personal accident history. Participants who reported involvement in more than three accidents or involvement in a severe accident perceived road travel as less risky and also reported behaving less safely compared with those involved in fewer, or less severe accidents. The results have practical implications for the prevention of traffic accidents.Practitioner Summary: The associations between accident history, perceived risk of road travel and safe behaviour were investigated using self-report questionnaire data. Participants involved in more than three accidents, or in severe accidents, perceived road travel as less risky and also reported more unsafe behaviour compared with those involved in fewer, or less severe accidents. Campaigns targeting people with a less serious, less extensive accident history should aim to increase awareness of hazards and the potential severity of their consequences, as well as emphasising how easy it is to take the recommended preventive actions. Campaigns targeting those involved in more frequent accidents, and survivors of serious accidents, should address feelings of invulnerability and helplessness. 相似文献
110.
《Ergonomics》2012,55(7):874-894
During laparoscopic surgery video images are used to guide the movements of the hand and instruments, and objects in the operating field often obscure these images. Thus, surgeons often rely heavily on tactile information (sense of touch) to help guide their movements. It is important to understand how tactile perception is affected when using laparoscopic instruments, since many surgical judgements are based on how a tissue ‘feels’ to the surgeon, particularly in situations where visual inputs are degraded. Twelve naïve participants used either their index finger or a laparoscopic instrument to explore sandpaper surfaces of various grits (60, 100, 150 and 220). These movements were generated with either vision or no vision. Participants were asked to estimate the roughness of the surfaces they explored. The normal and tangential forces of either the finger or instrument on the sandpaper surfaces were measured. Results showed that participants were able to judge the roughness of the sandpaper surfaces when using both the finger and the instrument. However, post hoc comparisons showed that perceptual judgements of surface texture were altered in the no vision condition compared to the vision condition. This was also the case when using the instrument, compared to the judgements provided when exploring with the finger. This highlights the importance of the completeness of the video images during laparoscopic surgery. More normal and tangential force was used when exploring the surfaces with the finger as opposed to the instrument. This was probably an attempt to increase the contact area of the fingertip to maximize tactile input. With the instrument, texture was probably sensed through vibrations of the instrument in the hand. Applications of the findings lie in the field of laparoscopic surgery simulation techniques and tactile perception. 相似文献