全文获取类型
收费全文 | 129878篇 |
免费 | 2431篇 |
国内免费 | 2001篇 |
专业分类
教育 | 89967篇 |
科学研究 | 14733篇 |
各国文化 | 199篇 |
体育 | 11072篇 |
综合类 | 8910篇 |
文化理论 | 86篇 |
信息传播 | 9343篇 |
出版年
2024年 | 13篇 |
2023年 | 357篇 |
2022年 | 1560篇 |
2021年 | 2934篇 |
2020年 | 3657篇 |
2019年 | 2458篇 |
2018年 | 1508篇 |
2017年 | 1604篇 |
2016年 | 1868篇 |
2015年 | 3706篇 |
2014年 | 9061篇 |
2013年 | 8968篇 |
2012年 | 10858篇 |
2011年 | 11152篇 |
2010年 | 7996篇 |
2009年 | 7063篇 |
2008年 | 7908篇 |
2007年 | 9303篇 |
2006年 | 8966篇 |
2005年 | 7661篇 |
2004年 | 6744篇 |
2003年 | 5831篇 |
2002年 | 4714篇 |
2001年 | 3688篇 |
2000年 | 2078篇 |
1999年 | 798篇 |
1998年 | 498篇 |
1997年 | 329篇 |
1996年 | 310篇 |
1995年 | 172篇 |
1994年 | 167篇 |
1993年 | 104篇 |
1992年 | 73篇 |
1991年 | 27篇 |
1990年 | 25篇 |
1989年 | 28篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 19篇 |
1984年 | 13篇 |
1983年 | 11篇 |
1982年 | 18篇 |
1981年 | 12篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 9篇 |
1977年 | 9篇 |
1976年 | 9篇 |
1957年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 749 毫秒
1.
《Information processing & management》2023,60(2):103226
Nowadays assuring that search and recommendation systems are fair and do not apply discrimination among any kind of population has become of paramount importance. This is also highlighted by some of the sustainable development goals proposed by the United Nations. Those systems typically rely on machine learning algorithms that solve the classification task. Although the problem of fairness has been widely addressed in binary classification, unfortunately, the fairness of multi-class classification problem needs to be further investigated lacking well-established solutions. For the aforementioned reasons, in this paper, we present the Debiaser for Multiple Variables (DEMV), an approach able to mitigate unbalanced groups bias (i.e., bias caused by an unequal distribution of instances in the population) in both binary and multi-class classification problems with multiple sensitive variables. The proposed method is compared, under several conditions, with a set of well-established baselines using different categories of classifiers. At first we conduct a specific study to understand which is the best generation strategies and their impact on DEMV’s ability to improve fairness. Then, we evaluate our method on a heterogeneous set of datasets and we show how it overcomes the established algorithms of the literature in the multi-class classification setting and in the binary classification setting when more than two sensitive variables are involved. Finally, based on the conducted experiments, we discuss strengths and weaknesses of our method and of the other baselines. 相似文献
2.
《Information processing & management》2023,60(2):103212
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
3.
ABSTRACT We compared cardiometabolic demand and post-exercise enjoyment between continuous walking (CW) and time- and intensity-matched interval walking (IW) in insufficiently active adults. Sixteen individuals (13 females and three males, age 25.3 ± 11.1 years) completed one CW and one IW session lasting 30 min in a randomised-counterbalanced design. For CW, participants walked at a mean intensity of 65–70% predicted maximum heart rate (HRmax). For IW, participants alternated between 3 min at 80% HRmax and 2 min at 50% HRmax. Expired gas was measured throughout each protocol. Participants rated post-exercise enjoyment following each protocol. Mean HR and V˙O2 showed small positive differences in IW vs. CW (2, 95%CL 0, 4 beat.min?1; d = 0.23, 95%CL 0.06, 0.41 and 1.4, 95%CL 1.2 ml.kg?1.min?1, d = 0.36, 95%CL 0.05, 0.65, respectively). There was a medium positive difference in overall kcal expenditure in IW vs. CW (25, 95%CL 7 kcal, d = 0.58, 95%CL 0.33, 0.82). Post-exercise enjoyment was moderately greater following IW vs. CW (9.1, 95%CL 1.4, 16.8 AU, d = 0.62, 95%CL 0.06, 0.90), with 75% of participants reporting IW as more enjoyable. Interval walking elicits meaningfully greater energy expenditure and is more enjoyable than CW in insufficiently active, healthy adults. 相似文献
4.
The focus of this paper is on a group of pupils with reading and writing difficulties who have been participating in an intervention study using assistive technology. That intervention study contained supervised training sessions with reading and writing tasks using an iPad with special supportive applications. The current study is a qualitative investigation of whether there has been any transfer from the intervention, to the pupils’ everyday school activities. Interviews with pupils and their teachers and observations during classroom lectures have been used to collect data. The results show that the pupils were positive to the assistive technology (the applications on the iPads), they found the apps easy to learn how to use and they appreciated the benefits they could give. Even so, only a few of the pupils had found use for and continued to use the tools after the intervention period finished. Possible reasons are that when the novelty wore off, students reverted to their usual study habits and that older students with many teachers and different classrooms were less able to adapt to using the apps. To improve transfer, it is suggested to introduce assistive technology earlier to students, in the younger grades, before study habits have been formed and to inform teachers about the use of AT in the classroom, including what is available and how it can benefit students. 相似文献
5.
Gale Macleod Robin Dallas-Childs Colin Brough Martin Toye 《Journal of Research in Special Educational Needs》2021,21(Z1):25-35
In this article we examine the complex relationship between care experience, mental health and exclusion from school and how young people (YP) negotiate these different experiences and identities. The study is a secondary analysis, informed by symbolic interactionist theory, of interviews conducted with 19 care experienced YP in Scotland. Not all of the YP were excluded and not all had a formal mental health diagnosis, as such our study design allows interrogation of the contexts and relationships which not only facilitate but also disrupt pathways to exclusion. It also allows reconsideration of assumptions of vulnerability which are often applied to care experienced YP. Our findings suggest that these YP are moving beyond ‘role playing’ the identities ascribed to them and actively seek out relationships which enable them to construct alternative identities. 相似文献
6.
《左传》是我国首部以编年为次序、以鲁国十二公为传主,系统记述春秋战国时期历史,对中国文化产生了巨大影响的文史作品。文章在概述《左传》文化价值的基础上,梳理了两千多年来关于《左传》文本与作者的主要学术争论,甄别《左传》流变过程中的22个关键文本。 相似文献
7.
Obesity is a complex disease with multiple contributing factors.One of the most intensely studied factors during the past decade has been the gut microbiota,which is the community of all microbes in the intestinal tract.The gut microbiota,via energy extraction,inflammation,and other actions,is now recognized as an important player in the pathogenesis of obesity.Dysbiosis,or an imbalance in the microbial community,can initiate a cascade of metabolic disturbances in the host.Early life is a particularly important period for the development of the gut microbiota,and perturbations such as with antibiotic exposure can have long-lasting consequences for host health.In early life and throughout the life span,diet is one of the most important factors that shape the gut microbiota.Although diets high in fat and sugar have been shown to contribute to dysbiosis and disease,dietary fiber is recognized as an important fermentative fuel for the gut microbiota and results in the production of short-chain fatty acids that can act as signaling molecules in the host.One particular type of fiber,prebiotic fiber,contributes to changes in the gut microbiota,the most notable of which is an increase in the abundance of Bifidobacterium.This review highlights our current understanding of the role of gut microbiota in obesity development and the ways in which manipulating the microbiota through dietary means,specifically prebiotics,could contribute to improved health in the host,including musculo skeletal health. 相似文献
8.
9.
改革开放后,中国经济不断发展,人们生活水平不断提高。国家需要培养包括德、智、体、美、劳5个方面都符合要求的人才,我国在教育方面的投入很多。这就是我国进行体育教育的原因,引起了前所未有的关注。然而,在传统的中学教育的影响下,一些学校仍然没有发展体育教育,而是用文化课程代替了体育教育。为了提高学生的身体质量,作为当前学校体育运动强劲发展的一部分,中学应继续关注体育锻炼并改善体育锻炼,这很可能需要根据各个学生的兴趣来实施。为了提高中学生的体育表现,学校需要明确体育锻炼目标,使中学生的身体素质得到全面提高。 相似文献
10.
学生的健康会直接决定国民健康水平。因为传统教育理念的影响,体育教育并不被重视的,按时随着近些年全民锻炼等意识理念的不断推广,学生体质问题越发突出,持续提高体育教育整体质量水平显得非常重要。对此,为了进一步提升体育教育质量,本文简要分析高校学生体质健康的影响因素与学校体育的应对策略,希望可以为相关教育者提供一定帮助。 相似文献