全文获取类型
收费全文 | 27278篇 |
免费 | 980篇 |
国内免费 | 367篇 |
学科分类
工业技术 | 28625篇 |
出版年
2024年 | 69篇 |
2023年 | 261篇 |
2022年 | 446篇 |
2021年 | 606篇 |
2020年 | 588篇 |
2019年 | 325篇 |
2018年 | 258篇 |
2017年 | 361篇 |
2016年 | 581篇 |
2015年 | 949篇 |
2014年 | 2509篇 |
2013年 | 1546篇 |
2012年 | 2501篇 |
2011年 | 2951篇 |
2010年 | 2749篇 |
2009年 | 2275篇 |
2008年 | 1630篇 |
2007年 | 1737篇 |
2006年 | 1364篇 |
2005年 | 1014篇 |
2004年 | 860篇 |
2003年 | 770篇 |
2002年 | 628篇 |
2001年 | 504篇 |
2000年 | 376篇 |
1999年 | 209篇 |
1998年 | 107篇 |
1997年 | 68篇 |
1996年 | 64篇 |
1995年 | 53篇 |
1994年 | 36篇 |
1993年 | 23篇 |
1992年 | 23篇 |
1991年 | 25篇 |
1990年 | 19篇 |
1989年 | 10篇 |
1988年 | 14篇 |
1987年 | 11篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1967年 | 4篇 |
1966年 | 6篇 |
1962年 | 5篇 |
1960年 | 3篇 |
1959年 | 5篇 |
1957年 | 4篇 |
1956年 | 3篇 |
1955年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 578 毫秒
101.
介绍了病理学精品课程网站的建设以及在线考试系统的实现技术,从提高网站建设和在线测试质量的角度研究探讨了在线测试系统。该系统对病理学课程教学质量和水平的提高能起到积极的促进作用,并可在其他课程的标准化考试中推广应用。 相似文献
102.
Cleyo Harris Travis O. Brenden Chris S. Vandergoot Matthew D. Faust Seth J. Herbst Charles C. Krueger 《Journal of Great Lakes research》2021,47(1):48-58
Infrequent captures of invasive, non-native grass carp (Ctenopharyngodon idella) have occurred in Lake Erie over the last 30+ years, with recent evidence suggesting wild reproduction in the lake’s western basin (WB) is occurring. Information on grass carp movements in the Laurentian Great Lakes is lacking, but an improved understanding of large-scale movements and potential areas of aggregation will help inform control strategies and risk assessment if grass carp spread to other parts of Lake Erie and other Great Lakes. Twenty-three grass carp captured in Lake Erie’s WB were implanted with acoustic transmitters and released. Movements were monitored with acoustic receivers deployed throughout Lake Erie and elsewhere in the Great Lakes. Grass carp dispersed up to 236 km, with approximately 25% of fish dispersing greater than 100 km from their release location. Mean daily movements ranged from <0.01 to 2.49 km/day, with the highest daily averages occurring in the spring and summer. The Sandusky, Detroit, and Maumee Rivers, and Plum Creek were the most heavily used WB tributaries. Seventeen percent of grass carp moved into Lake Erie’s central or eastern basins, although all fish eventually returned to the WB. One fish emigrated from Lake Erie through the Huron-Erie Corridor and into Lake Huron. Based on our results, past assessments may have underestimated the potential for grass carp to spread in the Great Lakes. We recommend focusing grass carp control efforts on Sandusky River and Plum Creek given their high use by tagged fish, and secondarily on Maumee and Detroit Rivers. 相似文献
103.
姜弘道 《水利水电科技进展》2021,41(1):8-8
新时代的治水方针和水利工程补短板、水利行业强监管的水利改革发展总基调对水利科技人才培养提出了多样化的需求。为适应需求,在列举专业认证对水利类专业建设与改革的促进以及分析尚存不足的基础上,提出了应通过加强学习、深入思考和顶层设计以加快推进专业建设与改革,并建议从着力培养复合型人才、加快培养模式改革、推进课程体系与课程设置改革、加强实践教学体系建设、创新课程与师资队伍建设、强化校企合作与产教融合、改进教育教学方式方法、完善质量保证体系等八方面加以实施。 相似文献
104.
Roberto Truzoli Veronica Pirola Stella Conte 《Journal of Computer Assisted Learning》2021,37(4):940-952
The lockdown due to COVID-19 in Italy resulted in the sudden closure of schools, with a shift from traditional teaching to the online one. Through an online questionnaire, this survey explores teachers' experience of online teaching, the level of risk factors (e.g., stress) and protective factors (e.g., locus of control) and their impact on satisfaction levels during the social distancing. One hundred seven high school teachers from Lombardy, an Italian region very affected by the COVID-19 outbreak, participated. Results show that depression and stress are the main predictors of satisfaction levels for online teaching. In addition, coping, locus of control and self-efficacy emerge as important protective factors. Finally, although there is great satisfaction with the online teaching experience, critical elements emerged. This study is relevant because it describes the critical elements of the online teaching experience, and identifies some protective factors and the main risk factors in teachers operating in an area strongly marked by social restrictions imposed by the pandemic. High school teachers emerge as a sub-group of the general population with specific psychological reactions. Considering the results, it is possible to suggest providing high-quality educational support and crisis-psychological oriented services to teachers, and help to maintain the psychological well-being. 相似文献
105.
Laura Menabò Alessandra Sansavini Antonella Brighi Grace Skrzypiec Annalisa Guarini 《Journal of Computer Assisted Learning》2021,37(6):1566-1577
Background: The rapid spread of COVID-19 forced many countries to adopt severe containment measures, transferring all didactic activities into virtual environments. However, the integration of technology in teaching may present difficulties, especially in some countries, such as Italy. Objectives: The present study analyzed how the two main factors of the Technology Acceptance Model (TAM), namely perceived usefulness and perceived ease of use, combined with online teaching self-efficacy, were associated with the intention to use technology to teach. We posited a moderated moderation model in which perceived usefulness represented the main predictor, with self-efficacy and perceived ease of use as moderators of intention to use technology to teach. Method: The model was tested through multiple regressions, using the PROCESS macro on SPSS 26 with a sample of 178 upper secondary school teachers in Italy. Results and conclusions: Regressions showed that each variable significantly predicted the intention to use technology. In addition, a moderation effect of self-efficacy on the perceived usefulness of using technology was found for medium and high-level of perceived ease of use of technology. Implications: The present study provides targeted implications for distance education policy and practice to promote its adoption (or the blended modality) in Italian upper schools. 相似文献
106.
Key areas of robot agility include methods that increase capability and flexibility of industrial robots and facilitate robot re-tasking. Manual guidance can achieve robot agility effectively, provided that a safe and smooth interaction is guaranteed when the user exerts an external force on the end effector. We approach this by designing an adaptive admittance law that can adjust its parameters to modify the robot compliance in critical areas of the workspace, such as near and on configuration singularities, joint limits, and workspace limits, for a smooth and safe operation. Experimental validation was done with two tests: a constraint activation test and a 3D shape tracing task. In the first one, we validate the proper response to constraints and in the second one, we compare the proposed approach with different admittance parameter tuning strategies using a drawing task where the user is asked to guide the robot to trace a 3D profile with an accuracy or speed directive and evaluate performance considering path length error and execution time as metrics, and a questionnaire for user perception. Results show that appropriate response to individual and simultaneous activation of the aforementioned constraints for a safe and intuitive manual guidance interaction is achieved and that the proposed parameter tuning strategy has better performance in terms of accuracy, execution time, and subjective evaluation of users. 相似文献
107.
108.
109.
21世纪是以计算机和网络技术为特征的世纪,信息技术在社会各个领域得到了广泛的应用,信息化课堂教学作为信息技术应用于教学的核心,也是目前我国推进教育信息化进程中的重、难点。尽管信息化课堂教学正如火如荼地开展,但仍存在许多弊端,从而导致信息化课堂教学流于形式。本文通过对目前信息化课堂教学存在的弊端及成因进行分析,提出并讨论了利用信息技术优化课堂教学的有效性措施。 相似文献
110.
在信息技术高速发展的今天,现代教育技术在大学物理实验教学中的应用已逐步得到普及。本文从教学实际出发,研究了现代教育技术在大学物理实验课程教学中的应用,并从教学实践角度思考如何有效地运用现代教育技术来调动学生的学习积极性和主动性,提高教学效果。 相似文献