全文获取类型
收费全文 | 2638篇 |
免费 | 233篇 |
国内免费 | 113篇 |
专业分类
电工技术 | 114篇 |
综合类 | 329篇 |
化学工业 | 93篇 |
金属工艺 | 70篇 |
机械仪表 | 118篇 |
建筑科学 | 165篇 |
矿业工程 | 66篇 |
能源动力 | 66篇 |
轻工业 | 54篇 |
水利工程 | 78篇 |
石油天然气 | 25篇 |
武器工业 | 29篇 |
无线电 | 116篇 |
一般工业技术 | 196篇 |
冶金工业 | 273篇 |
原子能技术 | 22篇 |
自动化技术 | 1170篇 |
出版年
2025年 | 21篇 |
2024年 | 43篇 |
2023年 | 45篇 |
2022年 | 60篇 |
2021年 | 66篇 |
2020年 | 68篇 |
2019年 | 65篇 |
2018年 | 77篇 |
2017年 | 66篇 |
2016年 | 77篇 |
2015年 | 79篇 |
2014年 | 130篇 |
2013年 | 142篇 |
2012年 | 168篇 |
2011年 | 181篇 |
2010年 | 169篇 |
2009年 | 154篇 |
2008年 | 178篇 |
2007年 | 153篇 |
2006年 | 181篇 |
2005年 | 98篇 |
2004年 | 108篇 |
2003年 | 70篇 |
2002年 | 89篇 |
2001年 | 75篇 |
2000年 | 46篇 |
1999年 | 30篇 |
1998年 | 26篇 |
1997年 | 36篇 |
1996年 | 34篇 |
1995年 | 25篇 |
1994年 | 30篇 |
1993年 | 35篇 |
1992年 | 28篇 |
1991年 | 18篇 |
1990年 | 12篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 9篇 |
1985年 | 10篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1979年 | 3篇 |
1975年 | 3篇 |
1964年 | 4篇 |
1957年 | 2篇 |
1956年 | 2篇 |
排序方式: 共有2984条查询结果,搜索用时 0 毫秒
61.
系统层次灰关联分析与应用 总被引:2,自引:0,他引:2
将灰色系统分解为若干灰色分系统,进而提出了系统层次灰关联分析法,计算表明,该方法用于水电工程排序以及多层次水利水电规划设计方案的优选是一条新的可行的途径。 相似文献
62.
周长江 《计算机与数字工程》2009,37(3):144-145
VS201SH视野检查系统的软件控制基于Windows平台和VC6.0开发环境,使用了对象建模方法和消息、多线程机制。系统通过人性化的操作界面,实NT高可靠性,强扩展性的医疗视野控制检查功能。该系统实NT盲点、青光眼、黄斑、低视力、区域、阈值等视野检查功能。 相似文献
63.
陈中标 《南京工业职业技术学院学报》2009,9(2):81-83
分别用定义法、关系矩阵、关系图、C语言程序法判断关系是否具有传递性,特别对关系矩阵法作了改进。当关系中元素比较多时,程序法是一种新而快的方法。 相似文献
64.
为利用TSP各物探指标预测隧道围岩质量,以G575线巴里坤~哈密公路东天山隧道为工程依托,利用灰色关联分析理论,建立了以岩体质量指标修正值作为围岩质量的依据,以9个物探指标为影响因素,采用MATLAB软件对隧道围岩质量的影响因素进行关联排序,确定影响围岩质量的主次因素;再选取高关联度的物探指标,采用灰色关联理论进行围岩质量预测。结果表明,波速、纵横波速比、泊松比、密度为影响隧道围岩稳定性的主控因素;剪切模量、拉梅系数、体积模量、动态杨氏模量、静态杨氏模量为次要因素;围岩质量预测采用波速、纵横波速比、泊松比、密度这4个高关联度的物探指标能准确预测隧道围岩分类。 相似文献
65.
Tomoyuki Fujii Keiichiro Tohgo Masafumi Fujioka Muhamad Safwan Bin Muhamad Azmi Kodai Kikushima Yoshinobu Shimamura 《Fatigue & Fracture of Engineering Materials & Structures》2020,43(9):1917-1927
This paper proposes an alternating bending technique for evaluating fatigue life in the low‐to‐high cycle fatigue regime. A method was developed for estimating the stress, elastic strain, and plastic strain ranges of a plastically deformed specimen subjected to alternating bending with consideration of stress and strain distributions. To evaluate its effectiveness, fatigue testing was conducted using a specimen made of a steel used for pressure vessels. The stress, elastic strain, and plastic strain ranges could be obtained during cyclic bending. The elastic strain amplitude life and plastic strain amplitude life curves were linear in a log–log plot in the low‐to‐high cycle fatigue regime. Hence, the fatigue life under alternating bending could be evaluated using the proposed strain‐based approach. However, these curves could not be predicted using equations with parameters obtained from tensile testing, such as the universal slope method, due to the strain gradient in the specimen. 相似文献
66.
In order to discuss the kinds of reasoning a visualization supports and the conclusions that can be drawn within the analysis context, a theoretical framework is needed that enables a formal treatment of the reasoning process. Such a model needs to encompass three stages of the visualization pipeline: encoding, decoding and interpretation. The encoding details how data are transformed into a visualization and what can be seen in the visualization. The decoding explains how humans construct graphical contexts inside the depicted visualization and how they interpret them assigning meaning to displayed structures according to a formal reasoning strategy. In the presented model, we adapt and combine theories for the different steps into a unified formal framework such that the analysis process is modelled as an assignment of meaning to displayed structures according to a formal reasoning strategy. Additionally, we propose the ConceptGraph, a combined graph-based representation of the finite-state transducers resulting from the three stages, that can be used to formalize and understand the reasoning process. We apply the new model to several visualization types and investigate reasoning strategies for various tasks. 相似文献
67.
L. El Hafi S. Isobe Y. Tabuchi Y. Katsumata H. Nakamura T. Fukui 《Advanced Robotics》2020,34(3-4):157-172
Human–robot interaction during general service tasks in home or retail environment has been proven challenging, partly because (1) robots lack high-level context-based cognition and (2) humans cannot intuit the perception state of robots as they can for other humans. To solve these two problems, we present a complete robot system that has been given the highest evaluation score at the Customer Interaction Task of the Future Convenience Store Challenge at the World Robot Summit 2018, which implements several key technologies: (1) a hierarchical spatial concepts formation for general robot task planning and (2) a mixed reality interface to enable users to intuitively visualize the current state of the robot perception and naturally interact with it. The results obtained during the competition indicate that the proposed system allows both non-expert operators and end users to achieve human–robot interactions in customer service environments. Furthermore, we describe a detailed scenario including employee operation and customer interaction which serves as a set of requirements for service robots and a road map for development. The system integration and task scenario described in this paper should be helpful for groups facing customer interaction challenges and looking for a successfully deployed base to build on. 相似文献
68.
《International Journal of Hydrogen Energy》2020,45(3):2319-2330
As it is important to achieve higher combustion efficiency for applications of micro-cylindrical combustor, the multi-factor impact mechanism on the combustion efficiency of a hydrogen-fuelled micro-cylindrical combustor is investigated in this work. Firstly, six factors such as hydrogen/air equivalence ratio, inlet velocity, inlet temperature, wall thermal conductivity, wall emissivity and convective heat transfer coefficient of outer wall and five levels of each factor are determined. Orthogonal design table L25(56) is introduced to arrange cases. Secondly, grey relational analysis is adopted to investigate the effects of the six factors on combustion efficiency. Finally, the results of grey relational analysis are validated by analysis of variance. Based on grey relational analysis and analysis of variance, it is determined that the impact ranking from the largest to the smallest is hydrogen/air equivalence ratio, inlet velocity and inlet temperature, followed by the other three factors. The impact of wall thermal conductivity, convective heat transfer coefficient of outer wall and wall emissivity is considered to be equal due to their difference of impact on combustion efficiency is very small. This work provides us significant reference for optimizing combustion efficiency of a hydrogen-fuelled micro-cylindrical combustor. 相似文献
69.
输电线路覆冰与导线温度和微气象参数关联分析 总被引:5,自引:4,他引:5
针对目前微气象参数等与覆冰的相关性分析不全面、不系统,无法确定主要影响因素的问题。统计了贵州电网输电线路覆冰在线监测系统于2008年冬末至2009年春末监测到的线路覆冰状况,指出线性相关分析定量结果与定性分析不符,提出了一种邓氏灰色关联度和灰色斜率关联度相结合的灰色综合关联分析方法,并确定了覆冰和各个参数(导线温度和环境温度、相对湿度、风速等微气象参数等)之间的关联度。结果表明:海拔高度对覆冰的严重程度和持续时间均有一定的影响;环境温度、导线温度、相对湿度和风速均与覆冰存在较大相关性,其中环境温度和导线温度与覆冰的相关性明显强于相对湿度和风速,即温度是影响覆冰的主要因素。 相似文献
70.
基于灰色关联理论的中国能源需求影响因素研究 总被引:1,自引:0,他引:1
能源是国民经济的基础产业和战略性资源,是保障和促进经济增长与社会发展的重要物质基础,随着经济的高速发展,我国对能源的需求总量呈现出稳定增长的发展趋势。从我国能源市场的现状出发,从经济学的角度对我国能源需求的主要影响因素进行定性分析,并通过灰色关联理论实证研究能源需求与影响能源需求的主要因素能源价格、经济的增长、人口、产业结构、能源消费结构、消费者的收入水平之间的关系,最后提出切合我国实际的能源发展对策。 相似文献