The study of temporal trends in altmetrics is under-developed, and this multi-year observation study addresses some of the deficits in our understanding of altmetric behaviour over time. The attention surrounding research outputs, as partially captured by altmetrics, or alternative metrics, constitutes many varied forms of data. Over the years 2008-2013, a set of 7739 papers were sampled on six occasions. Five altmetric data sources were recorded (Twitter, Mendeley, News, Blogs and Policy) and analysed for temporal trends, with particular attention being paid to their Open Access status and discipline. Twitter attention both starts and ends quickly. Mendeley readers accumulate quickly, and continue to grow over the following years. News and blog attention is quick to start, although news attention persists over a longer timeframe. Citations in policy documents are slow to start, and are observed to be growing over a decade after publication. Over time, growth in Twitter activity is confirmed, alongside an apparent decline in blogging attention. Mendeley usage is observed to grow, but shows signs of recent decline. Policy attention is identified as the slowest form of impact studied by altmetrics, and one that strongly favours the Humanities and Social Sciences. The Open Access Altmetrics Advantage is seen to emerge and evolve over time, with each attention source showing different trends. The existence of late-emergent attention in all attention sources is confirmed.

翻译：替代计量的时间趋势研究尚不充分，这项历时多年的观测研究弥补了我们对替代计量行为随时间演变理解的不足。研究产出所引发的关注（部分通过替代计量或替代指标得以捕捉）构成了多种形式的数据。在2008-2013年间，我们分六次对7739篇论文进行了抽样，记录了五种替代计量数据来源（Twitter、Mendeley、新闻、博客和政策文件），并重点分析了其时间趋势，特别关注开放获取状态和学科领域。Twitter的关注度启动和消退均十分迅速。Mendeley读者积累迅速，并在随后数年持续增长。新闻和博客的关注启动较快，但新闻关注的持续时间更长。政策文件中的引用启动缓慢，且观察到其在发表后十年间持续增长。随时间推移，Twitter活跃度增长得到确认，而博客关注度明显下降。Mendeley使用量呈增长态势，但近期显示出下降迹象。政策关注被确认为替代计量研究中最慢的影响形式，且强烈偏向人文社会科学领域。开放获取替代计量优势随时间显现并演变，每种关注来源呈现不同趋势。所有关注来源均确认存在晚期涌现的关注现象。