全文获取类型
收费全文 | 8531篇 |
免费 | 610篇 |
国内免费 | 650篇 |
专业分类
电工技术 | 155篇 |
技术理论 | 13篇 |
综合类 | 1223篇 |
化学工业 | 146篇 |
金属工艺 | 33篇 |
机械仪表 | 63篇 |
建筑科学 | 1240篇 |
矿业工程 | 142篇 |
能源动力 | 60篇 |
轻工业 | 205篇 |
水利工程 | 182篇 |
石油天然气 | 25篇 |
武器工业 | 7篇 |
无线电 | 416篇 |
一般工业技术 | 515篇 |
冶金工业 | 2957篇 |
自动化技术 | 2409篇 |
出版年
2024年 | 30篇 |
2023年 | 117篇 |
2022年 | 173篇 |
2021年 | 277篇 |
2020年 | 318篇 |
2019年 | 302篇 |
2018年 | 306篇 |
2017年 | 333篇 |
2016年 | 359篇 |
2015年 | 397篇 |
2014年 | 536篇 |
2013年 | 632篇 |
2012年 | 449篇 |
2011年 | 591篇 |
2010年 | 524篇 |
2009年 | 521篇 |
2008年 | 488篇 |
2007年 | 448篇 |
2006年 | 435篇 |
2005年 | 406篇 |
2004年 | 337篇 |
2003年 | 313篇 |
2002年 | 259篇 |
2001年 | 225篇 |
2000年 | 77篇 |
1999年 | 59篇 |
1998年 | 27篇 |
1997年 | 28篇 |
1994年 | 24篇 |
1993年 | 22篇 |
1992年 | 26篇 |
1990年 | 31篇 |
1989年 | 21篇 |
1988年 | 25篇 |
1987年 | 21篇 |
1986年 | 20篇 |
1981年 | 18篇 |
1966年 | 26篇 |
1965年 | 28篇 |
1964年 | 58篇 |
1963年 | 47篇 |
1962年 | 18篇 |
1961年 | 45篇 |
1960年 | 23篇 |
1959年 | 31篇 |
1958年 | 22篇 |
1957年 | 34篇 |
1956年 | 25篇 |
1955年 | 47篇 |
1954年 | 28篇 |
排序方式: 共有9791条查询结果,搜索用时 15 毫秒
41.
社会网络是通过朋友关系、工作关系和信息交换等一组社会机制,将人、组织和其他社会团结联系在一起形成的网络,Web就是一种社会网络.在社会网络中要求有一种自然的机制对网络的真实性进行判断和评价,信任模型就是比较好的一种机制.基于社会网络,本文构建了一种网络信任模型,用来估算信任者和被信任者之间的信任等级,能够用于语义网的信任管理系统和社会网络的信任评价中.实验结果表明,该模型具有很好的效率和效果. 相似文献
42.
为了快速准确地找到在线社会网络的社区结构,提出了一种基于共同好友数和节点邻居信息的社区结构发现算法。该算法以共同好友数最多的两个节点为初始社区,不断寻找与社区连接性最强的节点,并以节点Q值为衡量标准,判断是否将该节点加入到初始社区中,最后根据节点邻居所在初始社区信息确定最终的社区划分。针对两个经典社会网络和人工生成网络数据的实验划分结果表明,该算法是可行和有效的。 相似文献
43.
44.
In group assessment, the focus is on finding high‐authority experts to improve the reliability of assessment results. In this study, we propose an authority updating algorithm while considering the power and judgement reliability of an expert on the basis of social networks and post‐evaluations. A network power index is established and used to reflect the power of an expert while considering social networks. The measurement of the judgement reliability of an expert considers the post‐evaluation of the objects selected by experts, thereby more scientifically reflecting the reliability of experts. The analysis shows the following: although the social‐network structure influences the authority of experts, the influence weakens when the assessment group is a highly or even fully connected group; the network effect may increase the authority of some experts and reduce that of others, and it will weaken as the network connectivity increases; moreover, the judgement reliability and authority of an expert while considering post‐evaluation can encourage him/her to make fair assessments and strive to reduce his/her motivation and cognitive biases. 相似文献
45.
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
46.
Nowadays, cities are the most relevant type of human settlement and their population has been endlessly growing for decades. At the same time, we are witnessing an explosion of digital data that capture many different aspects and details of city life. This allows detecting human mobility patterns in urban areas with more detail than ever before. In this context, based on the fusion of mobility data from different and heterogeneous sources, such as public transport, transport‐network connectivity and Online Social Networks, this study puts forward a novel approach to uncover the actual land use of a city. Unlike previous solutions, our work avoids a time‐invariant approach and it considers the temporal factor based on the assumption that urban areas are not used by citizens all the time in the same manner. We have tested our solution in two different cities showing high accuracy rates. 相似文献
47.
Huihua Liu Eva Bracht Xin‐an Zhang Bret Bradley Rolf van Dick 《Creativity & Innovation Management》2021,30(1):129-143
An increasing number of individuals work in jobs with little standardization and repetition, that is, with high levels of job non‐routinization. At the same time, demands for creativity are high, which raises the question of how employees can use job non‐routinization to develop creativity. Acknowledging the importance of social processes for creativity, we propose that transformational leaders raise feelings of organizational identification in followers and that this form of identification then helps individuals to develop creativity in jobs with little routinization. This is because organizational members evaluate and promote those ideas as more creative, which are in line with a shared understanding of creativity within the organization. To investigate these relationships, we calculated a mediated moderation model with 173 leader–follower dyads from China. Results confirm our hypotheses that transformational leadership moderates the relationship between job non‐routinization on employee creativity through organizational identification. We conclude that raising feelings of social identity is a key task for leaders today, especially when working in uncertain and fast developing environments with little repetition and the constant need to develop creative ideas. 相似文献
48.
针对目前已有社会化网络服务对社会影响的研究更侧重于青少年,对老年人群体研究相对较少的情况,本文研究了面向老年人的社会化网络服务平台,介绍了平台的体系结构,阐述了社交系统、数据分析和信息服务。此平台利用面向老年人的社交网络服务系统获得用户行为数据,在数据集成、时空数据仓库存储的基础上,通过建立老年人社会网络行为的数学模型,运用统计学方法进行建模分析,分析结果可为多层次人员提供不同的信息服务。 相似文献
49.
Carmen Ferrer-Prez Marina D. Reguiln Jos Miarro Marta Rodríguez-Arias 《International journal of molecular sciences》2021,22(5)
There is huge scientific interest in the neuropeptide oxytocin (OXT) due to its putative capacity to modulate a wide spectrum of physiological and cognitive processes including motivation, learning, emotion, and the stress response. The present review seeks to increase the understanding of the role of OXT in an individual’s vulnerability or resilience with regard to developing a substance use disorder. It places specific attention on the role of social stress as a risk factor of addiction, and explores the hypothesis that OXT constitutes a homeostatic response to stress that buffers against its negative impact. For this purpose, the review summarizes preclinical and clinical literature regarding the effects of OXT in different stages of the addiction cycle. The current literature affirms that a well-functioning oxytocinergic system has protective effects such as the modulation of the initial response to drugs of abuse, the attenuation of the development of dependence, the blunting of drug reinstatement and a general anti-stress effect. However, this system is dysregulated if there is continuous drug use or chronic exposure to stress. In this context, OXT is emerging as a promising pharmacotherapy to restore its natural beneficial effects in the organism and to help rebalance the functions of the addicted brain. 相似文献
50.
论大学生社会责任感的培养 总被引:17,自引:0,他引:17
社会责任感的重要性在当今社会里凸显出来。可是,在多种因素的作用下,部分大学生的社会责任感却趋于淡化,这使大学生难以担负起历史的重任。对于部分大学生重才而轻德的现象,高等教育应该承担一定社会责任,这种社会责任就在于强化大学生的社会责任感。 相似文献