首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2689篇
  免费   54篇
  国内免费   25篇
电工技术   26篇
综合类   619篇
化学工业   103篇
金属工艺   26篇
机械仪表   50篇
建筑科学   437篇
矿业工程   9篇
能源动力   7篇
轻工业   88篇
水利工程   15篇
石油天然气   4篇
武器工业   3篇
无线电   89篇
一般工业技术   46篇
冶金工业   801篇
原子能技术   2篇
自动化技术   443篇
  2023年   12篇
  2022年   21篇
  2021年   52篇
  2020年   33篇
  2019年   24篇
  2018年   22篇
  2017年   46篇
  2016年   59篇
  2015年   55篇
  2014年   177篇
  2013年   117篇
  2012年   152篇
  2011年   206篇
  2010年   180篇
  2009年   188篇
  2008年   188篇
  2007年   154篇
  2006年   146篇
  2005年   145篇
  2004年   161篇
  2003年   123篇
  2002年   100篇
  2001年   66篇
  2000年   38篇
  1999年   28篇
  1998年   13篇
  1997年   8篇
  1996年   7篇
  1995年   8篇
  1994年   8篇
  1989年   11篇
  1988年   13篇
  1987年   11篇
  1986年   10篇
  1981年   8篇
  1975年   6篇
  1972年   7篇
  1971年   4篇
  1965年   8篇
  1964年   10篇
  1963年   9篇
  1962年   9篇
  1961年   8篇
  1960年   9篇
  1959年   6篇
  1958年   5篇
  1957年   12篇
  1956年   13篇
  1955年   12篇
  1954年   8篇
排序方式: 共有2768条查询结果,搜索用时 15 毫秒
1.
刘飞菲 《数字通信世界》2021,(4):146-147,189
在新时期下,传统的英语教学方法已经不适合学生的学习和发展了,经过笔者的研究和分析发现,小学生对故事似乎是非常感兴趣,所以就针对多媒体技术在小学英语故事教学中的应用进行了几点尝试。  相似文献   
2.
Vegetable intake is far below recommendations among African-American adolescents living in economically-underserved urban areas. While the National School Lunch Program (NSLP) helps overcome access barriers, vegetable intake remains challenging and novel interventions are required. A two-year, multi-phase, school-based intervention was conducted at an urban, economically-underserved, and predominantly African-American high school in Baltimore, Maryland to determine whether stakeholder-informed addition of spices and herbs to NSLP vegetables would increase intake. The stakeholder engagement phase included assessment of NSLP vegetable attitudes/preferences among 43 school stakeholders and subsequent student sensory testing. The second phase was conducted in the school cafeteria and consisted of eight weeks comparing student intake of typical vegetable recipes versus otherwise-identical recipes with spices and herbs. 4570 student lunch plates were included in the vegetable intake comparison. Vegetable intake was measured by lunch tray plate waste. Willingness to try vegetables was assessed by the difference between plate waste and estimated mean vegetable served weight. Intake of typical vegetable recipes and vegetable recipes with spices and herbs was compared with student’s t-test. Chi-square test was used to compare willingness to try vegetables. Total vegetable intake was 18.2% higher (8.22 g per meal, p < 0.0001) with spices and herbs than with typical recipes. There were no differences in trying vegetables with spices and herbs, although student-led advocacy was associated with increased trying vegetables with spices and herbs (78.8% with advocacy, 67.5% without advocacy, p < 0.0001). The addition of spices and herbs to vegetables in the NSLP was feasible and associated with small increases in vegetable intake at an urban, economically-underserved, and predominantly African-American high school.  相似文献   
3.
ABSTRACT

The time displacement hypothesis has been widely used to explain the effects of media use on academic performance. This approach has been criticised for its monocausality and weak explanatory power. Utilising a combination of different theoretical perspectives is better suited than utilising only one. Considering displacement, excitement, attraction and third variable hypothesis, this paper argues that the relation between video game use and school performance is not the same for all types of gamers by considering the influence of socioeconomic, psychological and contextual factors. It investigates how gaming patterns (frequency, time of day) and psychological characteristics (sensation seeking, aggression) are related to academic performance for primary and secondary school students. Five hundred and seven students from five primary and four secondary schools in Singapore participated in a paper-pencil survey. Results showed support for a combination of displacement and third variable hypothesis, as overall time spent on video games was negatively associated with primary school children’s and active gamers’ school performances. There was no significant relationship for secondary school children. For primary school children who play games in the morning and afternoon, video game use was negatively associated with school performance. There was no support for the attraction and excitement hypotheses.  相似文献   
4.
The paper is mainly to explore the automated music composition experiences for the students in the high grades of elementary school who are unfamiliar with the professional music theory. The proposed Automated Composition for Music Education (ACME) software was developed to help the students to compose the rhythm and melody themselves, while chord configuration and arrangement are automatically generated. Subsequently, sixth-year students of a non-experimental school were recruited to use the software for the completion of its development. Analysis of learning effectiveness at the reaction level, analysis of learning-level learning effectiveness, correlation analysis of the reaction- and learning-levels learning effectiveness has been performed with a significant result. The correlations between each component of learning effectiveness at the reaction and learning levels were also found. Finally the students in the experimental group using the ACME teaching materials showed a better learning effectiveness at both reaction level and learning level, than those of the students in the comparison group.  相似文献   
5.
如何在互联网时代打造一个信息化的管理模式,已经成为广大学校图书管理发展过程中亟待处理的问题。文章就互联网时代下的高职图书管理信息化建设进行了详细探讨,以期能够给广大同仁提供一些借鉴参考,共同为图书管理工作的现代化改革和发展贡献力量。  相似文献   
6.
The loss of infrastructure functionality for a community from a tornado can significantly affect economic vitality and result in substantial social disruption. The duration of the loss of functionality is a decisive factor in the magnitude of the economic disruption caused by a tornado. Therefore, quantitative models for the post-tornado restoration processes are needed in order to provide risk-informed decision support. In this study, the water network, electric power network, school buildings, residential buildings and businesses were modelled with their relative spatial distribution along with select dependencies and cross-dependencies in order to investigate the restoration of a community in the aftermath of a disaster. A tornado path was simulated using statistics from a historical tornado database. Based on the damage level of the components and their connectivity throughout the community, the functionality of the supplier nodes was assessed through a Monte Carlo simulation. Finally, the repair time of the damaged components was modelled to capture how the demands may be satisfied over time until eventually full restoration is achieved. Then, two metrics were defined to highlight business and social disruption following a tornado. The approach presented herein can be implemented in future studies to quantify indirect economic loss and social disruption resulting from a tornado.  相似文献   
7.
以无人机应用技术专业为例,探索基于现代学徒制课程体系的构建。由构建基于现代学徒制课程体系的基本要求和依据出发,分析了现代学徒制专业课程体系特征,描述现代学徒制专业课程体系建设原则与思路,重点阐述了现代学徒制专业课程体系基本组成以及构建方法,为相关现代学徒制课程体系的构建提供参考。  相似文献   
8.
The advent of high-throughput sequencing methods allowed researchers to fully characterize microbial community in environmental samples, which is crucial to better understand their health effects upon exposures. In our study, we investigated bacterial and fungal community in indoor and outdoor air of nine classrooms in three elementary schools in Seoul, Korea. The extracted bacterial 16S rRNA gene and fungal ITS regions were sequenced, and their taxa were identified. Quantitative polymerase chain reaction for total bacteria DNA was also performed. The bacterial community was richer in outdoor air than classroom air, whereas fungal diversity was similar indoors and outdoors. Bacteria such as Enhydrobacter, Micrococcus, and Staphylococcus that are generally found in human skin, mucous membrane, and intestine were found in great abundance. For fungi, Cladosporium, Clitocybe, and Daedaleopsis were the most abundant genera in classroom air and mostly related to outdoor plants. Bacterial community composition in classroom air was similar among all classrooms but differed from that in outdoor air. However, indoor and outdoor fungal community compositions were similar for the same school but different among schools. Our study indicated the main source of airborne bacteria in classrooms was likely human occupants; however, classroom airborne fungi most likely originated from outdoors.  相似文献   
9.
一年一度的“中国设计理论与‘中国工匠’培育高端论坛”旨在探讨、研究与实践中国设计理论体系的当代建构问题,以期对中国未来发展做出中国设计理论界自己的努力和贡献。本研究聚焦设计与技术之内在逻辑关系的探讨,重点探索中国设计理论与技术创新问题。系统考察与研究中国设计理论的概念、基本内涵、特征及其价值;深入探讨如何把握技术创新的基本内涵、价值追求及其当代意义;特别考察中国设计理论建设中的技术创新问题。本次的亮点是设计治理理论问题的提出与探索,具有极大的现实价值和理论意义。这些问题正是中国当代文化转型发展的重大理论问题。本研究尝试性探讨技术设计学体系建构的基本问题。  相似文献   
10.
黄旻  吴超 《新建筑》2007,(1):53-57
从建筑要素的基本构成入手,通过对建筑使用要求和基地自然环境的解读,确立了理性、亲切、开放、现代的滨海学校设计基调,并通过基本设计语言的运用达成设计概念,营造出轻盈和易识别的教学场所。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号