全文获取类型
收费全文 | 2175篇 |
免费 | 49篇 |
国内免费 | 60篇 |
专业分类
教育 | 1600篇 |
科学研究 | 403篇 |
各国文化 | 4篇 |
体育 | 70篇 |
综合类 | 90篇 |
文化理论 | 5篇 |
信息传播 | 112篇 |
出版年
2023年 | 17篇 |
2022年 | 20篇 |
2021年 | 72篇 |
2020年 | 66篇 |
2019年 | 101篇 |
2018年 | 58篇 |
2017年 | 63篇 |
2016年 | 57篇 |
2015年 | 57篇 |
2014年 | 148篇 |
2013年 | 281篇 |
2012年 | 206篇 |
2011年 | 189篇 |
2010年 | 102篇 |
2009年 | 115篇 |
2008年 | 113篇 |
2007年 | 129篇 |
2006年 | 130篇 |
2005年 | 87篇 |
2004年 | 73篇 |
2003年 | 62篇 |
2002年 | 45篇 |
2001年 | 33篇 |
2000年 | 20篇 |
1999年 | 13篇 |
1998年 | 11篇 |
1997年 | 7篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1988年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有2284条查询结果,搜索用时 953 毫秒
61.
According to the simple view of reading (SVR), reading comprehension relies on “decoding” (pseudoword, word reading) and “oral comprehension” skills. Testing 556 French pupils, we aimed at unpacking these two components and tracking their longitudinal development in first grade. We have found that: (1) lower level language skills (vocabulary, syntax) and discourse skills (oral text comprehension) emerged as two dimensions of “oral comprehension”; (2) lower level language skills longitudinally predicted reading comprehension outcomes, above code-related skills; (3) decoding precursors (letter knowledge, naming speed and phonemic awareness) predicted reading comprehension directly, and indirectly, through decoding skills (pseudoword, word reading, text reading fluency); (4) Oral comprehension skills did not favour the development of decoding. Our results support the independency of the SVR components. However, we suggest that a more fine-grained conceptualisation of oral comprehension skills would help to better understand the individual and pedagogical factors influencing the early development of reading comprehension. 相似文献
62.
冰是冰冻圈核心物质,但不同冰冻圈要素因冰的含量及其他物质组成有所不同,物理性质及各种物理过程存在明显差异。经过20世纪中后期对冰的物理性质的大量实验研究和冰冻圈主要要素物理特征的广泛调查,冰的物理性质和冰冻圈主要要素物理特征的基本概念得以明确。随着冰冻圈科学体系的建立和服务于社会经济发展的需要,冰冻圈物理研究在3个方面要着力发展:(1)提高冰和冰冻圈要素物理性质的定量刻画精度,为过程模拟、冰冻圈灾害防治和冰冻圈服务提供关键参数支持;(2)加强冰冻圈主要要素综合物理过程的模拟研究,特别是要开展实体和相似性模拟实验;(3)推进冰冻圈多模式及其与其他圈层模式的耦合研究。 相似文献
63.
Recent privacy-related incidents of mobile services have shown that app stores and providers face the challenge of mobile users’ information privacy concerns, which can prevent users from installing mobile apps or induce them to uninstall an app. In this paper, we investigate the role of app permission requests and compare the impact on privacy concerns with other antecedents of information privacy concerns, i.e., prior privacy experience, computer anxiety, and perceived control. To test these effects empirically, we conducted an online survey with 775 participants. Results of our structural equation modeling show that prior privacy experience, computer anxiety, and perceived control have significant effects on privacy concerns. However, concerns for app permission requests have approximately twice as much predictive value than the other factors put together to explain mobile users’ overall information privacy concerns. We expect that our findings can provide a theoretical contribution for future mobile privacy research as well as practical implications for app stores and providers. 相似文献
64.
Molecular hydrogen exerts biological effects on nearly all organs. It has anti-oxidative, anti-inflammatory, and anti-aging effects and contributes to the regulation of autophagy and cell death. As the primary organ for gas exchange, the lungs are constantly exposed to various harmful environmental irritants. Short- or long-term exposure to these harmful substances often results in lung injury, causing respiratory and lung diseases. Acute and chronic respiratory diseases have high rates of morbidity and mortality and have become a major public health concern worldwide. For example, coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global pandemic. An increasing number of studies have revealed that hydrogen may protect the lungs from diverse diseases, including acute lung injury, chronic obstructive pulmonary disease, asthma, lung cancer, pulmonary arterial hypertension, and pulmonary fibrosis. In this review, we highlight the multiple functions of hydrogen and the mechanisms underlying its protective effects in various lung diseases, with a focus on its roles in disease pathogenesis and clinical significance. 相似文献
65.
Growing evidence suggests that social identities may have profound implications for physical activity participation. Real-world examinations of this relationship have, however, been lacking, with research predominantly examining intentions and hypothetical scenarios. To address this shortcoming and further advance understanding in this area, the present study tested relationships between group identification, participation, two exercise-specific outcomes (exercise-specific satisfaction and group cohesion), and a broad health indicator (life satisfaction) among individuals recruited from parkrun. Participants (N = 289) completed questionnaires measuring all variables except participants’ parkrun participation, which was objectively assessed. Structural equation modeling demonstrated that group identification was significantly associated with greater participation, exercise-specific satisfaction, group cohesion, and life satisfaction. Findings provide real-world evidence of the health-related benefits associated with forming strong social identities in exercise settings. 相似文献
66.
[目的/意义]探讨知识贡献活动的制约因素及其作用机制,为专业虚拟社区的未来发展任务提供实证支撑。[方法/过程]通过扎根理论的部分程序抽取开放式访谈得到的制约因素,借助解释结构模型和行动者网络理论分析制约因素的作用机制。[结果/结论]18个知识贡献活动的制约因素整体上形成了一个复杂的由多级层序结构组成的动态行动者网络,涉及用户心理和状态、用户体验、系统功能与设计、信息质量以及运营机制五类行动者。专业虚拟社区需要把握未来发展任务的轻重缓解,首先解决信息质量和运营机制等关键问题。 相似文献
67.
焦允 《河南广播电视大学学报》2006,19(2):62-64
文章主要探讨统一建模语言(UML)与体系结构描述语言(ADL)在体系结构建模中的应用问题。首先,深入分析了UML/ADL在建模时各自的特点以及集成的可行性;然后,提出了一种把二者相结合的建模方案;最后,以一个外国专家管理信息系统为例,说明了UML/ADL的集成建模。 相似文献
68.
本文通过对机械制图与CAD的关系分析,指出三维几何造型是制图课程教改的内容之一,利用多媒体在机械制图几何画法和绘制组合体三视图等教学过程中运用CAD软件三维几何造型,充分发挥学生想象力,提高学生识图和绘图能力,培养设计和创新意识等;通过CAD二维辅助和三维几何造型训练,学生不仅了解了CAD软件,且能够认识到这种现代工具进行工程设计的便捷、准确性,以及CAD技能对工科大学生的重要性。 相似文献
69.
挣值管理方法忽视可交付物质量和工作间的逻辑关系对项目绩效测量和完工预测的影响,存在绩效偏差来源不清和进度度量不直观等问题。考虑可交付物质量及活动的时间特性,提出一种活动描述的元组模型,分析已完工和当前活动的绩效,进而计算路径进度绩效,据此调整项目的关键路径;同时,按照人力资源投入计划将活动分类,根据同类活动绩效预测项目完工尚需的时间和成本。一个移动物流社交网络系统开发项目管理实践验证了改进的挣值管理方法的可行性和有效性,符合项目实际情况。改进的方法适合大型及复杂项目的管理工作。 相似文献
70.
Previous studies have distinguished cognitive, occupational status and network mechanisms in the relation between education and ethnocentrism. Hypotheses on these mediating mechanisms are derived from socialization theory, realistic group threat and contact theory. In the current study we use structural equation modeling to investigate the explanatory power of these three mechanisms simultaneously. The analysis is based on a representative population survey from the Netherlands (NELLS 2009, n = 1910). The results show that more than half of the initial association between education and ethnocentrism can be attributed to cognitive ability and occupational status mechanisms. The remaining part of the overall association, however, still has to be modeled as a direct relationship between education and ethnocentrism. This direct association can be attributed either to social desirability or to a direct liberalizing effect of education on social and political attitudes. Our analysis tentatively suggests that the rise of average education levels in Western societies might lead to less ethnocentric attitudes via the cognitive sophistication mechanism. 相似文献