全文获取类型
收费全文 | 494篇 |
免费 | 5篇 |
国内免费 | 41篇 |
专业分类
教育 | 333篇 |
科学研究 | 120篇 |
各国文化 | 8篇 |
体育 | 15篇 |
综合类 | 15篇 |
文化理论 | 3篇 |
信息传播 | 46篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 16篇 |
2020年 | 20篇 |
2019年 | 17篇 |
2018年 | 13篇 |
2017年 | 19篇 |
2016年 | 8篇 |
2015年 | 16篇 |
2014年 | 33篇 |
2013年 | 55篇 |
2012年 | 41篇 |
2011年 | 37篇 |
2010年 | 22篇 |
2009年 | 31篇 |
2008年 | 31篇 |
2007年 | 42篇 |
2006年 | 32篇 |
2005年 | 11篇 |
2004年 | 21篇 |
2003年 | 19篇 |
2002年 | 11篇 |
2001年 | 13篇 |
2000年 | 9篇 |
1999年 | 5篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1988年 | 1篇 |
排序方式: 共有540条查询结果,搜索用时 15 毫秒
531.
532.
Rhonda A. Syler Casey G. Cegielski Sharon L. Oswald R. Kelly Rainer Jr. 《Decision Sciences Journal of Innovative Education》2006,4(1):51-65
The accelerating diffusion of broadband Internet access provides many opportunities for the development of pedagogically robust Web‐based instruction (WBI). While the supporting technology infrastructure of broadband disseminates, the attention of academic researchers focuses upon issues such as the drivers of student usage of WBI. Specifically, the research presented herein examined the impact of WBI on a student's aggregate course performance. We hypothesized that learning independence (LI) is a determinate factor in a student's use of WBI. In this study, we employed structural equation modeling techniques to examine the data and assess the direct and indirect effects of LI on WBI usage. The subjects, students in an introductory Computer Information Systems applications course, used a Web‐based tutorial program for skills instruction. The findings of this study suggest that WBI usage has a significant impact on a student's course performance. Despite its plausibility, the effect of LI on WBI usage was not significant. However, we did conclude that two of the second order factors of the LI construct have a direct effect on a student's performance in the course. 相似文献
533.
MBE growth of ZnSxSe1−x thin films on ITO coated glass substrates were carried out using ZnS and Se sources with the substrate temperature ranging
from 270°C to 330°C. The XRD σ/2σ spectra resulted from these films indicated that the as-grown polycrystalline ZnSxSe1−x thin films had a preferred orientation along the (111) planes. The evaluated crystal sizes as deduced from the FWHM of the
XRD layer peaks showed strong growth temperature dependence, with the optimized temperature being about 290 °C. Both AFM and
TEM measurements of these thin films also indicated a similar growth temperature dependence. High quality ZnSxSe1−x thin film grown at the optimized temperature had the smoothest surface with lowest RMS value of 1.2 nm and TEM cross-sectional
micrograph showing a well defined columnar structure.
Project supported by the National Science Council of PRC (No. 59910161981) and RGC grant from the Hong Kong Government under
Grant (No. NS-FC/HKUST 35) 相似文献
534.
混凝土作为最大宗的人造建筑材料,其废弃混凝土碎块的产生量也继续增多,对自然资源的占用及其对环境造成负面影响巨大。如何处理废弃混凝土碎块的问题将更趋严峻,因此提出了再生混凝土的概念。本文对再生混凝土结构性能在国内外研究现状进行论述,指出再生混凝土结构具有广阔的应用前景。 相似文献
535.
Technological adoption, with an emphasis on Information and Communications technology (ICT), is considered as a decisive factor for the overall development of each country. For this, the European Commission (EC) has launched a number of policy frameworks, aiming to enhance the usage and to improve the quality of European citizens' lives. However and so far, the results are still below the initial goals. Thus, the EC recently decided to set some additional targets, in order to facilitate a wider adoption of information services and maximize economical and societal benefits. 相似文献
536.
邱明会 《辽宁科技学院学报》2006,8(4):82-83
本文就闻一多新诗的“建筑美“理论进行探讨.他的“建筑美“理论分为两个方面:(一)属于视觉方面的;(二)属于听觉方面的.诗的建筑美是类属于格律之中的,也就是说是属于视觉方面的“节的匀称“和“句的均齐“.这一理论对中国新诗的发展起到了极其重要的作用.笔者欲通过对这一理论的探讨以便促进新诗“建筑美“的发展. 相似文献
537.
Characterization of a novel impurity in bulk drug of lisinopril by multidimensional NMR technique 总被引:1,自引:1,他引:0
During the routine impurity profile of lisinopril bulk drug by HPLC (high-performance liquid chromatography), a potential impurity was detected. Using multidimensional NMR (nuclear magnetic resonance) technique, the trace-level impurity was unambiguously identified to be 2-(-2-oxo-azocan-3-ylamino)-4-phenyl-butyric acid after isolation from lisinopril bulk drug by semi-preparative HPLC. Formation of the impurity was also discussed. To our knowledge, this is a novel impurity and not reported elsewhere. 相似文献
538.
This paper aims at time-series prediction of disease counts when the trend changes unexpectedly. There is a body of literature in time-series analysis that focuses on improving the prediction when a change in the trend is observed. Following this line of literature, a method was recently proposed that outperforms the previous proposals. To utilize this method for prediction of disease counts, the present study employs a commonly used method called local estimators for estimation near boundaries. This provides two advantages for disease count prediction. First, the prior method is limited to only smooth trend changes. However, the current study using local estimators also encounters abrupt changes. Taking both smooth and abrupt changes into account is important in predicting disease counts, because, for variety of different reasons, such as vaccination programs, the disease counts may encounter abrupt changes. Second, the current study, despite the previous approach, can also model uncertainty. The parameter uncertainty plays a significant role when predicting disease counts. Compared to current literature, the proposed method outperformed to predict counts for 12 diseases in Nevada. The paper demonstrates that the proposed methods improved the prediction Q-Score in comparison to both outbreak and structural change methods available in literature. Although this method has been specifically demonstrated for prediction of disease counts, it can be generalized for different applications. With the recent utilization of analytics techniques and the increased use of time-series analysis in information systems, the suggested method provides implications for the literature of information systems when predicting with structural trend changes in data. 相似文献
539.
The use of text-based chatbots offering individual support to customers has increased steadily in recent years. However, thus far, research has focused on comparing text-based chatbots with either each other or with humans, whilst the investigation of task-based dialogues has been scarce. This paper aims to identify the characteristics of dialogues – that is, conversational elements – that lead to a successful task-based conversation. For this purpose, the chatbot, KIM, by MAGGI Kochstudio was used. It was designed to help customers find a recipe tailored to their individual needs. In order to investigate which conversational elements contribute to successful communication between the user and the chatbot KIM, a usability study collecting 123 unstructured dialogues and a scenario-based experiment using four dialogues with 627 respondents was conducted. The quantitative analysis demonstrates that task completion is characterized by a higher perception of the chatbot’s conversational ability and user satisfaction. The chatbot should propose correct recipe suggestions following a short dialogue, without the user needing to provide too much input. Based on these findings, we recommended equipping the skillset of task-based chatbots with elements that will complement their assistive qualities – for example, improved use of standard phrases, and reactions to similar domains and non-requests. Gender-specific differences in task completion should be considered. 相似文献
540.
科技成果转化效能低一直是推进科技赋能、实现科技强国的阻力。为推动科技成果转化效能提升,需要从各要素出发,探索要素结构性差异和配置困境,助力科技成果转化全要素配置。结合TOE理论和扎根理论,构建包含技术、组织、环境3类主范畴、8类次范畴在内的高校科技成果转化要素分析框架,对16个不同领域高校科技成果转化案例分类进行对比。研究发现,高校科技成果转化要素配置结构主要分为4类:环境制约型、技术—组织依赖型、环境—组织依赖型、均衡配置型;要素配置困境主要来源于政府、市场、高校、专业服务机构、科研团队五大主体,当前存在顶层设计缺失、专业服务体系不健全、人才流失、技术与市场供需不匹配等困境。 相似文献