全文获取类型
收费全文 | 9803篇 |
免费 | 192篇 |
国内免费 | 186篇 |
专业分类
教育 | 6709篇 |
科学研究 | 1526篇 |
各国文化 | 6篇 |
体育 | 431篇 |
综合类 | 557篇 |
文化理论 | 11篇 |
信息传播 | 941篇 |
出版年
2024年 | 5篇 |
2023年 | 30篇 |
2022年 | 67篇 |
2021年 | 111篇 |
2020年 | 169篇 |
2019年 | 111篇 |
2018年 | 115篇 |
2017年 | 109篇 |
2016年 | 137篇 |
2015年 | 193篇 |
2014年 | 550篇 |
2013年 | 640篇 |
2012年 | 737篇 |
2011年 | 836篇 |
2010年 | 554篇 |
2009年 | 546篇 |
2008年 | 626篇 |
2007年 | 822篇 |
2006年 | 815篇 |
2005年 | 722篇 |
2004年 | 594篇 |
2003年 | 536篇 |
2002年 | 420篇 |
2001年 | 346篇 |
2000年 | 177篇 |
1999年 | 73篇 |
1998年 | 41篇 |
1997年 | 25篇 |
1996年 | 22篇 |
1995年 | 12篇 |
1994年 | 4篇 |
1993年 | 10篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 10篇 |
1989年 | 3篇 |
1979年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
论网站信息咨询服务模式 总被引:15,自引:0,他引:15
目前,对于网站信息咨询概念的认识尚不统一。网站信息咨询的主要模式有:基于资源重组的知识化信息服务,依托应用系统的智能化服务,基于用户需求的个性化服务,基于实时联动的交互式咨询服务等等。网站咨询服务具有快捷方便、超越时空、动态发布、资源共享、智能管理、安全可靠、实时交互、服务主动等优点。其存在的问题主要表现于思想认识、经费投入和技术、法规保证方面。参考文献8。 相似文献
62.
面向知识创新的信息服务 总被引:23,自引:0,他引:23
网络环境下面向知识创新的信息服务运作模式有两大类型:专业信息中心模式、虚拟社区模式。图书馆应积极探索智能化程度更高、更富人性化的服务和技术,包括建立个性化信息导引机制、“一步到位”式的参考链接服务、合作虚拟参考咨询服务以及集成式多语种检索服务。参考文献7。 相似文献
63.
64.
Black-dyed artefacts are found in museums worldwide, many produced using an iron-tannate compound. Deterioration of iron-tannate dyed artefacts is an international preservation issue: in New Zealand the deterioration of paru (iron-tannate) dyed Māori textiles is widespread. This article reports experimental work testing the efficacy of sodium alginate, a consolidant developed for deteriorated paru-dyed muka (fibre from harakeke; Phormium tenax). The colour stability, strength retention, and acidity of paru-dyed muka consolidated with sodium alginate (0.25, 0.5, and 1% w/v in water) was tested pre- and post-artificial light ageing. This study found that sodium alginate had no negative effect on paru-dyed muka and in some cases provided benefit. Interestingly, the colour of paru-dyed muka is substantially more stable in UV-filtered light than previously recognised. Also microfading results were in agreement with visual assessments of colour change at 1 Mlux hour exposure, providing confidence in this relatively new technique to assess colour change. 相似文献
65.
Bast fibres have been commonly used as a textile material in Northern Europe since Neolithic times. However, the process of identifying the different species has been problematic, and many important questions related to their cultural history are still unanswered. For example, a modified Herzog test and the presence of calcium oxalate crystals have both been used in identification. In order to generate more reliable results, further research and advancement in multi-methodological methods is required. This paper introduces a combination of methods which can be used to identify and distinguish flax (Linum usitatissimum), hemp (Cannabis sativa), and stinging nettle (Urtica dioica). The research material consisted of reference fibres and 25 fibre samples obtained from 12 textiles assumed to be made of nettle. The textiles were from the Finno-Ugric and Historical Collections of The National Museum of Finland. The fibre samples were studied by observing the surface characteristics and cross sections with transmitted light microscopy, and by using a modified Herzog test with polarized light, in order to identify the distinguishable features in their morphological structures. The study showed that five out of 25 samples were cotton, 16 nettle, one flax, and one hemp. Findings from two samples were inconsistent. The results show that it is possible to distinguish common north European bast fibres from each other by using a combination of microscopic methods. Furthermore, by utilizing these combined methods, new and more reliable information could be obtained from historical ethnographic textiles, which creates new vistas for the interpretation of their cultural history. 相似文献
66.
目前,学术界多开展引用动机和引文功能的相关研究,但对于引用偏好等引用行为却关注较少。基于Taylor的信息使用环境理论,本研究采用参考文献分析方法,全面揭示了施引者引用行为的特征和影响因素。研究将信息使用环境理论中的前三类要素分别通过学者特征、组织环境及论题进行定义,采用参考文献分析法提取第四类要素;随机抽取论文样本,针对上述四类特征进行编码并通过统计分析探讨影响施引者引用行为的因素。研究发现:学者的年龄、性别、教育水平、学术年龄、职业角色、职称、所属机构的类型和层次以及所从事的研究主题和类型,都能对质量、语种、数量、信息资源类型、论文新旧的引用偏好产生显著影响。研究表明:信息使用环境理论和参考文献分析法在引用行为研究中具有适用性。表4。参考文献47。 相似文献
67.
Jiawei Huang Mahda M. Bagher Heather Dohn Ross Nathan Piekielek Jan Oliver Wallgrün Jiayan Zhao 《Journal of Map & Geography Libraries》2018,14(1):40-63
Libraries have been the key to preserving culture and historic legacy for centuries. One such treasure cataloged in The Pennsylvania State University (Penn State) Libraries is a collection of over 33,000 Sanborn? Fire Insurance Maps. Originally kept safe in metal drawers, the library has embarked on a journey to digitize this abundance of information, combine it with other media such as photographs, and make it accessible through a web interface. Inspired by these efforts, we accessed this information and took it to the next level. Using state of the art 3D modeling and immersive technologies, we created a historic 3D model and immersive experiences of Penn State, exemplarily for the 1922 campus. The resulting experiences can be accessed through the web but also through head mounted displays (HMDs) and mobile phones in combination with VR viewers such as the Google Cardboard. Additionally, they can be used anywhere in the world or on the campus itself as a way to enable remote and in situ experiences and learning. Immersive experiences let us connect to the past, the present and the future, and as such offer value to digital cultural heritage efforts. 相似文献
68.
In this contribution, we develop a new approach to explore the process of knowledge transition from discovery-oriented science to technological fields, via applications-oriented research, including a mediator set. This trajectory is referred to as the D-A-T trajectory. It is shown how it can be constructed and measures are proposed to characterize the relational strength among different environments (discovery oriented research, applications-oriented research and patents) and the speed of evolution. Our approach is illustrated by a case study of three fundamental restriction enzymes articles. Among other results we found that 387 patents cited 124 of the 988 articles (a share of 12.55%) in the mediator set. Defining the non-patent references (NPR) transition rate as the number of citing patents divided by the number of articles in the mediator set yields a value 0.392. Our results suggest that the D-A-T path acts as a backbone and reveals important “invisible contributions” of an original scientific work during its evolution from discovery oriented research to outside academia. Our contribution provides a useful tool for bridging the existing gap in detecting the transition of knowledge between science and technology. 相似文献
69.
The aim of this study was to investigate the frequency of child physical maltreatment (CPM) in children with autism aged 2–5 years in Henan province (China), and to explore the risk factors for severe CPM in these children. This cross-sectional study was performed at the Psychology Clinic of the Third Affiliated Hospital of Zhengzhou University between September 2012 and September 2013 with 180 parents of children with autism. Children and parents had no history of any cognitive therapy. The childhood autism rating scale (CARS) was used to evaluate the severity of autism in children. Data on parental CPM during the past 3 months were collected from parental self-reporting. Logistic regression was used to investigate the risk factors of severe CPM. CPM was self-reported by 88% of the parents of children with autism. One hundred and fifty four of these cases were in the minor CPM group (86%) and 64 in the severe CPM group (36%). Most cases of severe CPM were unlikely to have caused injury. Univariate analyses showed that child's age (p = .018), age started to speak (p = .043) and CARS score (p = .048) were associated with severe CPM. Child's age (p = .011) and CARS score (p = .041) were independently associated with severe CPM. The risk of severe CPM increased with age and CARS score. Our findings showed that CPM is widespread in families of children with autism in Central China and more knowledge should be provided to parents of children with autism, particularly in cases of severe autism (those with high CARS scores). 相似文献
70.
Fernanda Somera dos Santos Mariana Kiomy Osako Gleici da Silva Castro Perdoná Márcia Gaião Alves Katiuchia Uzzun Sales 《Anatomical sciences education》2021,14(4):408-416
Virtual microscopy (VM) is a widely used teaching method in Medical Education in many developed countries. In Brazil, however, this is not the case for most medical schools, considering Brazilian social inequality and uneven access to technology. Recently, the Covid-19 pandemic has also challenged Universities to seek and make a transition toward more effective methods of full-time online education. Thus, the main goal of this work was to verify student's perception and academic performance, assessed upon VM implementation in a Brazilian Medical School. Ribeirao Preto Medical School students answered a 26-question survey with regards to optical microscopy (OM) and VM. Academic performance was compared between participants that were (year of 2019) or were not (year of 2015) exposed to VM. Taken the results together, subjective impressions such as handling, suitability, learning effectiveness, and pleasure using the tools, have shown a higher score for virtual microscopy (median = 29), when compared to optical microscopy (median = 24) with a P-value < 0.001 by Wilcoxon rank test, upon measurement using an ordinal scale. Regarding academic performance, no statistically significant differences were found between groups (P-value = 0.38, Cohen's d = 0.19). Therefore, VM proved to be adequate to the Brazilian medical education in light of Brazilian social contexts and Covid-19 pandemic. 相似文献