全文获取类型
收费全文 | 15438篇 |
免费 | 1646篇 |
国内免费 | 1270篇 |
专业分类
电工技术 | 838篇 |
技术理论 | 1篇 |
综合类 | 1332篇 |
化学工业 | 2470篇 |
金属工艺 | 451篇 |
机械仪表 | 699篇 |
建筑科学 | 1625篇 |
矿业工程 | 189篇 |
能源动力 | 535篇 |
轻工业 | 1077篇 |
水利工程 | 381篇 |
石油天然气 | 308篇 |
武器工业 | 162篇 |
无线电 | 1266篇 |
一般工业技术 | 2572篇 |
冶金工业 | 788篇 |
原子能技术 | 294篇 |
自动化技术 | 3366篇 |
出版年
2024年 | 111篇 |
2023年 | 430篇 |
2022年 | 722篇 |
2021年 | 760篇 |
2020年 | 641篇 |
2019年 | 573篇 |
2018年 | 544篇 |
2017年 | 647篇 |
2016年 | 646篇 |
2015年 | 619篇 |
2014年 | 956篇 |
2013年 | 1058篇 |
2012年 | 979篇 |
2011年 | 1039篇 |
2010年 | 755篇 |
2009年 | 820篇 |
2008年 | 821篇 |
2007年 | 860篇 |
2006年 | 742篇 |
2005年 | 685篇 |
2004年 | 561篇 |
2003年 | 495篇 |
2002年 | 453篇 |
2001年 | 357篇 |
2000年 | 302篇 |
1999年 | 267篇 |
1998年 | 222篇 |
1997年 | 196篇 |
1996年 | 151篇 |
1995年 | 166篇 |
1994年 | 108篇 |
1993年 | 91篇 |
1992年 | 84篇 |
1991年 | 72篇 |
1990年 | 75篇 |
1989年 | 72篇 |
1988年 | 64篇 |
1987年 | 33篇 |
1986年 | 17篇 |
1985年 | 22篇 |
1984年 | 19篇 |
1983年 | 21篇 |
1982年 | 15篇 |
1980年 | 9篇 |
1979年 | 8篇 |
1966年 | 6篇 |
1964年 | 6篇 |
1959年 | 7篇 |
1958年 | 5篇 |
1955年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
《Computer Speech and Language》2014,28(2):420-433
Automatic detection of a user's interest in spoken dialog plays an important role in many applications, such as tutoring systems and customer service systems. In this study, we propose a decision-level fusion approach using acoustic and lexical information to accurately sense a user's interest at the utterance level. Our system consists of three parts: acoustic/prosodic model, lexical model, and a model that combines their decisions for the final output. We use two different regression algorithms to complement each other for the acoustic model. For lexical information, in addition to the bag-of-words model, we propose new features including a level-of-interest value for each word, length information using the number of words, estimated speaking rate, silence in the utterance, and similarity with other utterances. We also investigate the effectiveness of using more automatic speech recognition (ASR) hypotheses (n-best lists) to extract lexical features. The outputs from the acoustic and lexical models are combined at the decision level. Our experiments show that combining acoustic evidence with lexical information improves level-of-interest detection performance, even when lexical features are extracted from ASR output with high word error rate. 相似文献
82.
介绍 4 0 0 kt/ a硫酸系统电除雾器总体结构及工艺设计参数 ,投入运行后 ,除雾效率低 ,介绍对存在问题的分析及解决过程 ,并介绍 2点成功经验 相似文献
83.
竹红菌甲素和吲哚类化合物的相互作用 总被引:2,自引:2,他引:2
本文利用吸收光谱,荧光光谱研究了竹红菌甲素(以下简称HA)和吲哚类化合物的相互作用。发现HA和吲哚类化合物在一定条件下可形成复合物。这种复合物带有电荷转移性质。吲哚环上带有给电子取代基,位阻小,溶剂的极性大和溶液呈中性有利于该复合物的形成。 相似文献
84.
In this paper, a nonlinear model reference adaptive impedance controller is proposed and tested. The controller provides asymptotic tracking of a reference impedance model for the robot end-effector in Cartesian coordinates applicable to rehabilitation robotics or any other human–robot interactions such as haptic systems. The controller uses the parameters of a desired stable reference model which is the target impedance for the robot’s end-effector. It also considers uncertainties in the model parameters of the robot. The asymptotic tracking is proven using Lyapunov stability theorem. Moreover, the adaptation law is proposed in joint space for reducing the complexity of its calculations; however, the controller and the stability proof are all presented in Cartesian coordinates. Using simulations and experiments on a two DOFs robot, the effectiveness of the proposed controller is investigated. 相似文献
85.
Electrostatic actuators have the advantages of light weight, flexibility, and high energy efficiency, which make them suitable for use as artificial muscles. However, a traditional electrostatic actuator cannot generate long strokes and a high force density at the same time because such actuator would excessively widen the gap between the electrodes because of its structure. This paper presents a newly developed large-scale stacked-type electrostatic actuator (LSEA) intended for use as an artificial muscle for robots. LSEA is a multi-stacked electrostatic actuator that can be linearly contracted by the application of a voltage. It has a unique structure that prevents overextension of the gap between the electrodes. It can therefore generate a large force. The spring characteristics and the relationship between the contractive force and the stroke were experimentally determined. The findings showed that LSEA prevents the overextension of the gap between the electrodes and has a high contraction ratio that is equivalent to that of a mammalian skeletal muscle. 相似文献
86.
《Robotics and Autonomous Systems》2014,62(3):392-399
Communication between socially assistive robots and humans might be facilitated by intuitively understandable mechanisms. To investigate the effects of some key nonverbal gestures on a human’s own engagement and robot engagement experienced by humans, participants read a series of instructions to a robot that responded with nods, blinks, changes in gaze direction, or a combination of these. Unbeknown to the participants, the robot had no form of speech processing or gesture recognition, but simply measured speech volume levels, responding with gestures whenever a lull in sound was detected. As measured by visual analogue scales, engagement of participants was not differentially affected by the different responses of the robot. However, their perception of the robot’s engagement in the task, its likability and its understanding of the instructions depended on the gesture presented, with nodding being the most effective response. Participants who self-reported greater robotics knowledge reported higher overall engagement and greater success at developing a relationship with the robot. However, self-reported robotics knowledge did not differentially affect the impact of robot gestures. This suggests that greater familiarity with robotics may help to maximise positive experiences for humans involved in human–robot interactions without affecting the impact of the type of signal sent by the robot. 相似文献
87.
根据电除尘器绝缘子的功能及工况条件,介绍了材质和结构形式的选择。对于电除尘器绝缘子材质的选择,首先要考虑承受运行电压的能力,其次是耐温性能和机械强度。对于结构形式的选择,应考虑有足够的厚度以耐电力冲击、足够大的爬电距离以防漏电或对地闪络、足够大的空间以防出现电晕或空间闪络。另外,介绍了高铝瓷绝缘子的成功应用及其优点。 相似文献
88.
用铬酸氧化法在聚乙烯薄膜的表面引入了羧基阴离子,合成了端基阳离子性的聚乙二醇重氮树脂,用静电自组装并辅以紫外光照射的方法,在聚乙烯薄膜的表面引入了共价键连接的聚乙二醇分子链.用紫外-可见分光光度法研究了重氮树脂及其静电自组装体系的光分解性质,得到重氮基团的分解速率常数kd=0.021 4 s-1.红外分析表明,紫外光照射后聚乙烯薄膜表面连接的聚乙二醇分子链可耐DMF-ZnC l2-H2O三元极性溶剂的刻蚀.由于在聚乙烯薄膜的表面引入了亲水性的聚乙二醇分子链,其表面接触角从改性前的104°降至48°. 相似文献
89.
Walter Brockmann 《The Journal of Adhesion》1989,29(1):53-61
Adequate adhesion between metals and polymers is primarily the result of chemical bonds in the boundary layer. This region, however, is subject to degradation by moisture. Three modes of deterioration are observed. The first is a largely reversible weakening effect in the polymer layer near the metal oxide surface. The structure of this layer differs from that of the bulk and is influenced by the chemical and physical properties of the surface. The second is a slow transformation of the oxide by hydration and a diffusion of oxide constituents into the polymer. This process is irreversible and is influenced by the state of the surface and chemical properties of the polymer. The third is a fast deterioration of the oxide by primary corrosion usually initiating at an unprotected edge but occasionally arising within the body of a joint. 相似文献
90.
结合现有两种主要群体推荐算法的优势, 建立新的算法框架, 并引入差异度因素对模型进行优化。另外, 考虑到在线社区用户的特点, 定义互动度指标来描述群体成员间的互动程度, 通过分析其与推荐精度之间的关系, 探讨互动度对群体推荐的影响。选取豆瓣网数据进行实验, 并与传统方法进行比较, 结果表明, 融入差异度的算法具有更好的推荐效果, 且有效的互动机制能够保证较高的推荐精度。 相似文献