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   6462篇
  免费   175篇
  国内免费   92篇
教育   4100篇
科学研究   1424篇
各国文化   3篇
体育   451篇
综合类   467篇
文化理论   19篇
信息传播   265篇
  2024年   1篇
  2023年   25篇
  2022年   86篇
  2021年   152篇
  2020年   186篇
  2019年   123篇
  2018年   123篇
  2017年   113篇
  2016年   152篇
  2015年   181篇
  2014年   406篇
  2013年   457篇
  2012年   571篇
  2011年   584篇
  2010年   491篇
  2009年   404篇
  2008年   403篇
  2007年   469篇
  2006年   452篇
  2005年   342篇
  2004年   284篇
  2003年   204篇
  2002年   170篇
  2001年   149篇
  2000年   81篇
  1999年   40篇
  1998年   7篇
  1997年   18篇
  1996年   12篇
  1995年   8篇
  1994年   6篇
  1993年   8篇
  1992年   4篇
  1991年   6篇
  1990年   1篇
  1989年   3篇
  1982年   2篇
  1981年   2篇
  1980年   1篇
  1957年   2篇
排序方式: 共有6729条查询结果,搜索用时 15 毫秒
1.
The massive number of Internet of Things (IoT) devices connected to the Internet is continuously increasing. The operations of these devices rely on consuming huge amounts of energy. Power limitation is a major issue hindering the operation of IoT applications and services. To improve operational visibility, Low-power devices which constitute IoT networks, drive the need for sustainable sources of energy to carry out their tasks for a prolonged period of time. Moreover, the means to ensure energy sustainability and QoS must consider the stochastic nature of the energy supplies and dynamic IoT environments. Artificial Intelligence (AI) enhanced protocols and algorithms are capable of predicting and forecasting demand as well as providing leverage at different stages of energy use to supply. AI will improve the efficiency of energy infrastructure and decrease waste in distributed energy systems, ensuring their long-term viability. In this paper, we conduct a survey to explore enhanced AI-based solutions to achieve energy sustainability in IoT applications. AI is relevant through the integration of various Machine Learning (ML) and Swarm Intelligence (SI) techniques in the design of existing protocols. ML mechanisms used in the literature include variously supervised and unsupervised learning methods as well as reinforcement learning (RL) solutions. The survey constitutes a complete guideline for readers who wish to get acquainted with recent development and research advances in AI-based energy sustainability in IoT Networks. The survey also explores the different open issues and challenges.  相似文献   
2.
ABSTRACT

This study operationalized Weick’s [(1988). Enacted sensemaking in crisis situations. Journal of Management Studies 25(4), 305–317 and (1993). The collapse of sensemaking in organizations: The Mann Gulch disaster. Administrative Science Quarterly, 38, 628–652] theory of enacted sensemaking to examine the communication processes associated with the Flint Water Crisis of 2014–2015. A content analysis of 389 emails and attachments from a total population of N?=?37,376 pages of publicly released e-mails and documents pertaining to Flint’s water issues, identified examples of failed sensemaking by government officials. These failures hastened and intensified a growing crisis of lead contamination and an outbreak of Legionnaires disease associated with Flint’s municipal water system. Analysis of email messages suggests that strong commitments by top leaders and limited capacity were important factors as were efforts to create and maintain consensus among officials. The Flint Water Crisis offers an important application of sensemaking theory and its utility for both organizational and risk communication scholars and for practical application. The authors emphasize the importance of questioning previous assumptions and commitments, insuring that communication practitioners are involved in decisions, and avoiding over reliance on image repair as a strategic response.  相似文献   
3.
In this article, I explore a Bayesian approach to avalanche decision-making. I motivate this perspective by highlighting a version of the base-rate fallacy and show that a similar pattern applies to decision-making in avalanche-terrain. I then draw out three theoretical lessons from adopting a Bayesian approach and discuss these lessons critically. Lastly, I highlight a number of challenges for avalanche educators when incorporating the Bayesian perspective in their curriculum.  相似文献   
4.
在对专家和领队访谈,对大学生徒步穿越活动参与者问卷调查,以及现场观察等调研的基础上,从户外运动风险源出发对上海市大学生徒步穿越风险管理问题进行系统分析,发现:大学生徒步穿越存在不少风险管理漏洞,但简单禁止活动开展反而会导致风险转移和扩散;应该着重从参与者等“人”的风险因素出发防范风险事故发生,以天气变化等部分“环境”风险因素应对进行探险体验,尽快提高指导教师和社团骨干的专业能力;高校应该对网约结伴方式参与徒步穿越活动进行风险警示,并强制性要求社团制定活动风险应急预案等。  相似文献   
5.
随着社会进步与教育环境诸多变化,中小学体育运动会风险管理亟需实现积极安全态度与现代技术防范并举。基于新时期中小学体育运动会风险评估是含有多重判断的复杂体系,该文引入层次全息建模HHM风险识别分析工具,构建包括运动会本体、组织管理、人员素质、场地设施、环境5大类别24个层次全息子系统的适用中小学体育运动会风险识别的全息模型,重点阐释了"组织管理——人员"风险识别的主场景,并通过HHM全息框架的指标转换、推演与扩展,统计中小学体育运动会风险清单全息模型配对的发生数目,运用层次分析法和帕累托分析法进行量化和评级,为中小学体育运动会风险量化评估提供参考依据。  相似文献   
6.
运用文献资料法和逻辑分析法,对冬季项目跨界跨项选材问题进行辩证分析。认为,2022年北京冬奥会、政府专项政策导向及国内外成功的跨界经验,为我国开展冬季项目跨界跨项选材工作提供了重要的机遇和支持,但跨界跨项选材任务艰巨、冬季项目人才缺口大、运动员培养时间不足、跨界跨项风险大等问题也不容忽视。为进一步做好跨界跨项选材工作,为我国冬季项目持续发展提供充足的人力支持,应积极落实国家政策,做到科学跨选;依托同项群项目选材,跨用传统优势项目人才;抓住冬奥发展机遇,尽快建立完善的人才培养体系。  相似文献   
7.
对功能性动作筛查(FMS)的国内外研究进行梳理,理清其发展脉络与研究动态。可以认为:在FMS的有效性、一致性、准确性等方面研究成果较多,但有关各类人群损伤风险临界值的确定、评分标准及与个体运动能力的相关性等研究领域仍处于停滞状态。除部分专业运动员之外,不同职业或年龄人群的评估研究数量仍偏少,而且评价缺乏相应的标准。结论:需要明确不同人群的FMS评价标准,进一步检验其损伤风险评估的临界值,重视不同人群的评价得分与训练反馈信息,为完善与推广FMS提供理论参考。  相似文献   
8.
Abstract

Institutional repositories (IRs) present platform to disseminate research findings to complement the traditional scholarly communication model. The use of IRs is beneficial to authors, host institutions, libraries and society at large. Despite the numerous benefits of IRs, there is low deposit of scholarly works by lecturers and the investment on IRs seems to be a waste. This study examined determinants of perceived ease of use (PEOU) of IRs by lecturers in Nigerian universities. A survey of lecturers received 857 respondents. Awareness, anchor and adjustment factors were found to be determinants of PEOU of Institutional repositories by lecturers in Nigerian Universities.  相似文献   
9.
Spatial ability (SA) is the cognitive capacity to understand and mentally manipulate concepts of objects, remembering relationships among their parts and those of their surroundings. Spatial ability provides a learning advantage in science and may be useful in anatomy and technical skills in health care. This study aimed to assess the relationship between SA and anatomy scores in first- and second-year medical students. The training sessions focused on the analysis of the spatial component of objects' structure and their interaction as applied to medicine; SA was tested using the Visualization of Rotation (ROT) test. The intervention group (n = 29) received training and their pre- and post-training scores for the SA tests were compared to a control group (n = 75). Both groups improved their mean scores in the follow-up SA test (P < 0.010). There was no significant difference in SA scores between the groups for either SA test (P = 0.31, P = 0.90). The SA scores for female students were significantly lower than for male students, both at baseline and follow-up (P < 0.010). Anatomy training and assessment were administered by the anatomy department of the medical school, and examination scores were not significantly different between the two groups post-intervention (P = 0.33). However, participants with scores in the bottom quartile for SA performed worse in the anatomy questions (P < 0.001). Spatial awareness training did not improve SA or anatomy scores; however, SA may identify students who may benefit from additional academic support.  相似文献   
10.
自甘风险和过失相抵是体育侵权案件中最常见的抗辩方式。前者将会免除加害人的赔偿责任,而后者只能按比例减少加害人的赔偿责任。虽然法律后果存在巨大差异,但目前对于体育侵权案件适用自甘风险,还是适用过失相抵,没有一个明确的标准,没有建构一套稳定的规则。从美国法的经验来看,通过对自甘风险进行分类来解决自甘风险和过失相抵的竞合问题,并不是一个成功的范例。实际上,自甘风险和过失相抵的主要区别在于受害人能否认知风险的存在。通过运动类型、违规程度、年龄和精神状况、参与的自愿性、专业程度等五个要素的综合考量,法官可以推知当事人的意思,进而从参加体育活动的行为来判断是否构成自甘风险,最终正确适用法律。  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