全文获取类型
| 收费全文 | 3776篇 |
| 免费 | 406篇 |
| 国内免费 | 85篇 |
专业分类
| 电工技术 | 87篇 |
| 技术理论 | 1篇 |
| 综合类 | 151篇 |
| 化学工业 | 134篇 |
| 金属工艺 | 14篇 |
| 机械仪表 | 92篇 |
| 建筑科学 | 351篇 |
| 矿业工程 | 44篇 |
| 能源动力 | 43篇 |
| 轻工业 | 372篇 |
| 水利工程 | 40篇 |
| 石油天然气 | 10篇 |
| 武器工业 | 20篇 |
| 无线电 | 354篇 |
| 一般工业技术 | 386篇 |
| 冶金工业 | 1084篇 |
| 原子能技术 | 7篇 |
| 自动化技术 | 1077篇 |
出版年
| 2025年 | 84篇 |
| 2024年 | 205篇 |
| 2023年 | 167篇 |
| 2022年 | 179篇 |
| 2021年 | 230篇 |
| 2020年 | 187篇 |
| 2019年 | 168篇 |
| 2018年 | 107篇 |
| 2017年 | 123篇 |
| 2016年 | 142篇 |
| 2015年 | 119篇 |
| 2014年 | 192篇 |
| 2013年 | 187篇 |
| 2012年 | 196篇 |
| 2011年 | 237篇 |
| 2010年 | 187篇 |
| 2009年 | 204篇 |
| 2008年 | 170篇 |
| 2007年 | 140篇 |
| 2006年 | 130篇 |
| 2005年 | 107篇 |
| 2004年 | 109篇 |
| 2003年 | 93篇 |
| 2002年 | 85篇 |
| 2001年 | 102篇 |
| 2000年 | 21篇 |
| 1999年 | 28篇 |
| 1998年 | 21篇 |
| 1997年 | 18篇 |
| 1996年 | 21篇 |
| 1995年 | 14篇 |
| 1994年 | 14篇 |
| 1993年 | 13篇 |
| 1992年 | 8篇 |
| 1989年 | 9篇 |
| 1988年 | 8篇 |
| 1985年 | 12篇 |
| 1984年 | 8篇 |
| 1983年 | 8篇 |
| 1981年 | 7篇 |
| 1965年 | 7篇 |
| 1964年 | 22篇 |
| 1963年 | 20篇 |
| 1961年 | 13篇 |
| 1960年 | 16篇 |
| 1959年 | 13篇 |
| 1958年 | 10篇 |
| 1957年 | 14篇 |
| 1956年 | 7篇 |
| 1955年 | 18篇 |
排序方式： 共有4267条查询结果，搜索用时 0 毫秒
81.
China, despite its rapid economic modernization and the lack of powerful conservative institutions, is not known for embracing diverse sexual orientation. The present study investigates whether and how Internet use, a increasingly important part of contemporary people's daily life, leads to changes in people's attitudes toward homosexuality in China, and relevant policy implications. Analyzing the Chinese General Social Survey data from 2010 to 2015, this paper develops an ordered probit model to quantify the influence of Internet use on homosexuality tolerance, adopts a substitution variable method to conduct the robustness check, and utilizes instrument variables to address the potential endogeneity in the regressions. The results show that Internet use has a significant positive impact on Chinese people's homosexuality tolerance. Further studies have found that the influence of Internet use on homosexuality tolerance is also heterogeneous to different populations. Besides, compared with traditional media, the Internet has a more significant impact on homosexuality tolerance. This paper provides some explanations for the rise in China's homosexuality tolerance from 2010 to 2015, and additional impetus for the international community to push for a liberal Internet policy in China. 相似文献
82.
《Displays》2020
Large-field optic flow generates the illusory percept of self-motion, termed ‘vection’. Smoother visual motion displays generate a more compelling subjective sense of vection and objective postural responses, as well as a greater sense of immersiveness for the user observing the visual display. Research suggests that the function linking frame rate and vection asymptotes at 60 frames per second (FPS), but previous studies have used only moderate frame rates that do not approach the limits of human perception. Here, we measure vection using subjective and objective (mean frequency and path length of postural centre-of-pressure (COP) excursions) responses following the presentation of high-contrast optic flow stimuli at slow and fast speeds and low and ultra-high frame rates. We achieve this using a novel rendering method implemented with a projector capable of sub-millisecond temporal resolution in order to simulate refresh rates ranging from very low (15 FPS) to ultra-high frame rates (480 FPS). The results suggest that subjective vection was experienced most strongly at 60 FPS. Below and above 60 FPS, subjective vection is generally weaker, shorter, and starts later, although this pattern varied slightly according to the speed of stimuli. For objective measures, while the frequency of postural sway was unaffected by frame rate, COP path length was greatest for 480 FPS stimuli. Together, our results support diminishing returns for vection above 60 FPS and provide insight into the use of high frame rate for enhancing the user experience in visual displays. 相似文献
83.
《Displays》2020
This study examines the essential effects of visual feedback on users’ perceptions of time and on their evaluations of waiting time for a mobile application user interface. The two variables adopted in this experiment are wait indicator visual feedback and waiting time. Three types of visual feedback were used: bar indicator, pie indicator, and cartoon indicator. Three waiting times were used: 2 s, 5 s, and 10 s. This study was conducted based on the attentional-gate model of Zakay and Block to help investigate user time perceptions. The experiment of this study was a 3 × 3 mixed factorial design to measure the impact of the research variables on the users’ perceptions of waiting time, wait evaluations, and preferences. Results showed that the users’ time perceptions and wait evaluations were affected by the feedback types and waiting times, and the results are consistent with Vierordt's law and the attentional-gate model. Furthermore, there was a positive impact on the participants' preferences when they perceived a shorter waiting time. The cartoon type feedback can help reduce the perception of waiting time, but it does not necessarily improve user experience regarding short waiting time. 相似文献
84.
在面料图像数据库系统中,为了让计算机对面料图像的情感语义进行自动感知,帮助用户用情感语义浏览或挑选所需的面料,并对其描述进行数值标注,文章针对面料图像本身表述的情感语义进行研究,进而实现基于情感语义的图像检索.在利用支持向量机等技术通过VC++编程实现面料图像情感语义识别的基础上,通过动态链接库技术将情感识别功能应用到... 相似文献
85.
板材心理感知颜色在线模糊分类器设计 总被引：1，自引：0，他引：1
为实现板材颜色的在线快速分类,解决深色珍贵木材难以识别的问题,建立一种基于模糊逻辑的颜色心理感知与物理量相关联的分类方法.以一种新的HSV颜色空间改进量化方法为基础,提取H、S分量特征值.再由语言值模糊化推理得到隶属度函数,选择Mamdani算法为模糊推理方法,以MIN-MAX-重心法进行解模糊,最后得到模糊规则查询表.模糊分类器对含9类树种、样本容量为1 000的一组板材进行分类.总体分类结果正确率为98.40％,平均处理速度约为每个样本40 ms.模糊分类器能够匹配工业相机的采集速度和传送带速度,可以实现在线分选,很好地克服深色纹理干扰,正确区分深红色板材与深色纹理板材. 相似文献
86.
As the population of elderly people in society rises, the importance of technology to assist health management is growing with the demographic shift. Wearable personal computing has been the common solution proposed by related projects to fulfil the needs of elderly people. These add-on devices are attached to the users, and result in uneasiness or discomfort while wearing them in public areas. In this study, three common wearing positions – wrist, upper arm, and neck – were investigated in terms of psychological perception and perceived readability. Twenty-four Taiwanese participants in Miaoli area were asked to wear the designed prototypes for a certain time. The participants completed questionnaires and participated in an open-ended interview. Data of psychological perceptions, visibility, and readability about wearable devices were collected. The results evidenced that the personal attributes of gender, smart device user, and requirement for medical care affect the psychological perception and user attitudes. The statistical results indicated significant differences in elderly people's attitudes towards wearable devices attached to different parts of the body. The wrist was the most favourable location to attach a wearable device. 相似文献
87.
E. Romero‐Hall G. S. Watson A. Adcock J. Bliss K. Adams Tufts 《Journal of Computer Assisted Learning》2016,32(4):360-373
This research assessed how emotive animated agents in a simulation‐based training affect the performance outcomes and perceptions of the individuals interacting in real time with the training application. A total of 56 participants consented to complete the study. The material for this investigation included a nursing simulation in which participants interacted with three animated agents. The results of this investigation indicated that both experienced and novice participants focused more visual attention time on the body of the animated agent than the other defined areas of interest in the simulated environment. The results also indicated that novice participants conveyed more neutral facial expressions during the interaction with the animated agents than experience participants. The results of the simulation performance scores indicated that novice participants achieved higher simulation performance scores on the simulation task than experienced participants. Lastly, the results of the agent persona instrument showed that experienced and novice participants perceived the animated agents as facilitators of learning, credible, human‐like and engaging. 相似文献
88.
This research proposes that it is possible to deliberately reduce temporal tensions in order to promote energy saving behaviours. People may not dedicate enough time to planning their tasks that consume energy, rushing into them without much deliberation. They may also use more energy than necessary in an attempt to accelerate processes that seem to be taking too long, to reduce the boredom of waiting. Persuasive technology provided the tools to manipulate the perception of time and therefore elicit changes in the specific behaviours that result in unnecessary energy usage. Cooking tasks were used as the scenario to test behaviour change strategies delivered via a smartphone application. Results showed that these strategies facilitated the performance of sustainable behaviours. Participants reported that the app made (1) them more likely to follow the steps needed to use less energy, (2) the activity more enjoyable and (3) the time appear to pass more quickly compared to a control version. 相似文献
89.
The visual ability factors of peripheral perception, visual reaction and visual pursuit ability are important for safe driving. Thus, this study explored the influence of driving experience on these visual ability factors. Sixty-five drivers, including novice and experienced drivers, participated in this study. The visual ability levels of the three factors were measured by the Vienna Test System. In addition, driver's awareness of the three factors' importance for safe driving was measured by questionnaire items. Results showed that out of the three factors, drivers' peripheral perception ability was correlated significantly with their driving experience. Experienced drivers had higher peripheral perception ability than that of novice drivers. In addition, compared with novice drivers, experienced drivers believed that peripheral perception was more important whereas visual reaction was less important. It is suggested that higher attention should be paid to peripheral perception in driving training and novice drivers should increase their importance awareness for this factor. 相似文献
90.
Osvaldo Da Pos Dhanraj Vishwanath Liliana Albertazzi 《Color research and application》2021,46(1):88-102
Although color plays a crucial role in the demarcation of surfaces in the visual field, its role in depth perception is not well understood. Certain special effects of color on depth perception that arise from optical factors such as chromatic aberration (chromostereopsis) have been studied, but less is known about the role of perceptual factors of color in determining depth relations. The present study explores the role that the different attributes of color such as hue, chroma, and lightness play in the stratification of surfaces in depth. In two experiments, subjects manipulated specific dimensions of colors (hue, chroma, lightness, and whiteness) while making judgments of coplanarity of either two or more abutting surfaces. The results demonstrate that for surfaces to appear coplanar, their lightness has to be proportional to the natural (intrinsic) lightness of the hues. No meaningful effects of chroma, whiteness, or blackness were found in depth stratification. The results suggest a primary role of the natural lightness of hues in depth perception. 相似文献