全文获取类型
收费全文 | 78746篇 |
免费 | 4301篇 |
国内免费 | 2618篇 |
专业分类
电工技术 | 4020篇 |
技术理论 | 26篇 |
综合类 | 6218篇 |
化学工业 | 10111篇 |
金属工艺 | 3689篇 |
机械仪表 | 4609篇 |
建筑科学 | 9679篇 |
矿业工程 | 4846篇 |
能源动力 | 2026篇 |
轻工业 | 7411篇 |
水利工程 | 1855篇 |
石油天然气 | 3724篇 |
武器工业 | 2118篇 |
无线电 | 8139篇 |
一般工业技术 | 3919篇 |
冶金工业 | 3730篇 |
原子能技术 | 300篇 |
自动化技术 | 9245篇 |
出版年
2024年 | 102篇 |
2023年 | 668篇 |
2022年 | 1567篇 |
2021年 | 2080篇 |
2020年 | 2072篇 |
2019年 | 1172篇 |
2018年 | 1039篇 |
2017年 | 1714篇 |
2016年 | 2028篇 |
2015年 | 2294篇 |
2014年 | 6155篇 |
2013年 | 4201篇 |
2012年 | 5886篇 |
2011年 | 6273篇 |
2010年 | 4795篇 |
2009年 | 4978篇 |
2008年 | 4506篇 |
2007年 | 5495篇 |
2006年 | 4984篇 |
2005年 | 4339篇 |
2004年 | 3749篇 |
2003年 | 3437篇 |
2002年 | 2779篇 |
2001年 | 2326篇 |
2000年 | 1755篇 |
1999年 | 1371篇 |
1998年 | 907篇 |
1997年 | 661篇 |
1996年 | 560篇 |
1995年 | 458篇 |
1994年 | 336篇 |
1993年 | 238篇 |
1992年 | 181篇 |
1991年 | 132篇 |
1990年 | 108篇 |
1989年 | 77篇 |
1988年 | 58篇 |
1987年 | 34篇 |
1986年 | 39篇 |
1985年 | 23篇 |
1984年 | 23篇 |
1983年 | 10篇 |
1982年 | 10篇 |
1981年 | 13篇 |
1980年 | 10篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1963年 | 2篇 |
1959年 | 2篇 |
1951年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Commercialization of technologies has attracted increasing attention over the past years due to its role in improving national competitiveness. Iran has not been an exception as the country's policy-makers have been actively engaged in crafting national policies to facilitate and promote commercialization of technologies. The popularity of the existing policies in this field, however, has not been properly researched. Our research, by following a survey study methodology, aims for the first time to address this gap. The study looks at popularity of governmental policies aimed at supporting commercialization of patented technologies in Iran, based on the careful study of 10 cases of successfully commercialized patented technologies in Iran. Our results indicate that the commercialization process of the studied patented technologies was very much affected by some company/technology-specific characteristics. The study shows that the two policy measures with the highest perceived popularity were the financial supports and the services offered by incubation centers. Our results also show that some of the existing supportive policy measures did not serve the intended purposes and some other measures need to be fine-tuned, as far as the studied cases are concerned, such as frequently held invention and innovation exhibitions and the government-supported media coverage. 相似文献
72.
Xipei Ren Bin Yu Yuan Lu Yu Chen Pearl Pu 《International journal of human-computer interaction》2019,35(10):870-885
This research was motivated by a desire to help office workers change their sedentary behavior because a prolonged sedentary posture increases the risks of developing musculoskeletal injuries and chronic diseases, thus threatening their physical and psychological well-being. Regular breaks involving low-effort physical activities are effective in reducing the adverse impacts of inactive behaviors. In this article, we present the design of a posture-based interactive system called HealthSit, which was developed to promote a short lower-back stretching exercise during work breaks. Through a within-subject study involving 30 office workers, the effectiveness of HealthSit in facilitating the stretching exercise was examined by making comparisons between an interaction-aided, a guided, and a self-directed exercise mode. We also used HealthSit as a research probe to investigate the interactivity of the system in enhancing user experience and the psychological benefits of the fitness breaks. Compared with the other two modes, the interaction-aided exercise mode significantly improved the quality of the stretching exercise and enhanced motivation and emotional state. These results confirm the effectiveness of HealthSit in supporting fitness breaks as a new workplace technology. Based on our study, a set of design implications have been derived for technology-assisted fitness work breaks. 相似文献
73.
以Orbit专利分析平台为主要研究工具,从专利文献中抽取专利数量指标和专利质量指标来构建评价薄板坯连铸连轧技术竞争力和企业创新能力的指标体系,结合其他文献研究的成果,从产业发展的实际出发做出分析,系统揭示了自薄板坯连铸连轧技术开发以来的技术进步、专利布局、发展演化、国内外发展现状、技术竞争实力等,有助于在专利文献提供的线索启发下开发新产品、新技术,从而有效提高研发效率。 相似文献
74.
Chingszu Lin Zhifeng Huang Masako Kanai-Pak Jukai Maeda Yasuko Kitajima Mitsuhiro Nakamura 《Advanced Robotics》2019,33(6):278-292
With the number of hospital stays increasing, nurses require more training to handle a variety of patients. However, time for training in nursing schools is limited, and students lack the opportunity to practice on a diverse variety of patients. Using a robot to simulate actual patients, this study observes the learning transfer effect of practice on practice-similar and practice-dissimilar skills from one patient to another, and investigates which types of practice suit which kinds of training. An experiment was conducted by administering a pre-test, practice, a post-test, and a transfer test to two groups (N?=?8), each with different practice-related skills. The evaluation used a checklist covering required skills that were either similar or dissimilar across groups, depending on their practice. The effect of practice can be observed through a comparison of skills similar to one group but dissimilar to the other. The results show that practice facilitates learning transfer on similar skills but not, or to a lesser degree, on dissimilar skills. Furthermore, if skills needed to handle given symptoms are unfamiliar or inaccessible to students, practice related to those symptoms should be emphasized through simulated training with robots. 相似文献
75.
《工程(英文)》2019,5(4):624-636
An intelligent manufacturing system is a composite intelligent system comprising humans, cyber systems, and physical systems with the aim of achieving specific manufacturing goals at an optimized level. This kind of intelligent system is called a human–cyber–physical system (HCPS). In terms of technology, HCPSs can both reveal technological principles and form the technological architecture for intelligent manufacturing. It can be concluded that the essence of intelligent manufacturing is to design, construct, and apply HCPSs in various cases and at different levels. With advances in information technology, intelligent manufacturing has passed through the stages of digital manufacturing and digital-networked manufacturing, and is evolving toward new-generation intelligent manufacturing (NGIM). NGIM is characterized by the in-depth integration of new-generation artificial intelligence (AI) technology (i.e., enabling technology) with advanced manufacturing technology (i.e., root technology); it is the core driving force of the new industrial revolution. In this study, the evolutionary footprint of intelligent manufacturing is reviewed from the perspective of HCPSs, and the implications, characteristics, technical frame, and key technologies of HCPSs for NGIM are then discussed in depth. Finally, an outlook of the major challenges of HCPSs for NGIM is proposed. 相似文献
76.
在“双一流”背景下,结合我校“工学并举”的办学特色,于电子技术基础专业课程中探索创新人才培养方法。根据“双一流”建设要求,更新教师和学生的观念,引导学生自主学习、主动实践、主动探索;采用“互联网+课堂”的教学模式,利用“课前(预习+问题)+课上(讲授+讨论)+课后(复习+举例)+课余(大作业+竞赛)”的互动模式;引入相关科技前沿,注重启发式教学,应用案例教学法,创设问题情境,开阔学生视野,培养学生的创新意识。通过科技竞赛等活动,促进学生的自主学习能力和实践能力,培养他们敢于尝试不怕失败的创新精神。 相似文献
77.
《Advanced Powder Technology》2019,30(11):2801-2811
Nanoparticles like quantum confined ZnS semiconductor nanocrystals, exhibit unique structure-property relationships. Narrow particle size distributions (PSDs) become one of the most important factors to tailor product performance. Size selective precipitation has already been proven to be an effective post processing strategy for ZnS nanoparticles. It is based on the titration of a poor liquid into a stable dispersion, which leads to the preferred flocculation of larger particles. Afterwards, these flocks must be separated from the continuous phase. While on lab scale the formed flocks can be easily separated by centrifugation from the fine fraction, for larger scale production using continuous processes, new concepts are urgently needed. Herein we developed a filtration process for flock removal that allows the handling of larger quantities. For process design, we first investigated the flock properties in order to know how stable the generated flocks are and how the flock properties can be controlled. Then, we replaced the classical flock separation by centrifugation through separation by surface filtration under the constraint that the underlying separation efficiency was not affected. By the future use of properly controlled, alternating filtration modules, our work opens the door for establishing an urgently needed, scalable post-processing for sub-10 nm nanoparticles. 相似文献
78.
Jaume Sastre‐Juan Jaume Valentines‐lvarez 《Centaurus; international magazine of the history of science and medicine》2019,61(1-2):2-13
How do nuclear technologies become commonplace? How have the borders between the exceptional and the banal been drawn and redrawn over the last 70 years in order to make nuclear energy part of everyday life? This special issue analyzes the role of fun and display, broadly construed, in shaping the cultural representation and the material circulation (or non‐circulation) of nuclear technologies. Four case studies, covering the United States, Great Britain, Portugal, Spain, and Ukraine from the 1950s to the 2000s, explore how specific forms of public display and playful practices of cultural production were used as means to banalize (or de‐banalize) nuclear energy. This introduction addresses the main theoretical and historiographical signposts of the special issue and outlines the different ways in which the articles explore them. 相似文献
79.
本文主要以新型建筑工业化与BIM技术的协同关系分析为重点阐述,结合当下建筑工业化和BIM技术两者关系、新型建筑工业要点、BIM技术基本作用和BIM技术和新型建筑工业化协同关系为主要依据,从能够创建关系矩阵、两者协同关系解释这几方面进行深入探索与研究,其目的在于加强BIM技术在新型建筑工业化中的运作效率。 相似文献
80.
华治国 《混凝土与水泥制品》2020,(6):70-72
选择了几份典型的外墙外保温系统标准,通过对这几份标准中胶粘剂和抹面胶浆的成型和检测方法的比较,分析了现有检测技术的优劣,并结合工作实践提出了建议。 相似文献