Top articles are divided into two categories of hot articles and articles of interest.
 
Hot papers:
 
Hot articles are articles that are ranked as one-tenth of a percent in terms of the number of citations received in their subject area.
 
Highly cited papers:
 
Articles are articles that are ranked as one percent in terms of the number of citations received in their subject area.
 
The timeframe for calculating hot articles is two months and for ten years' worth of articles.
 
How to identify top articles:
 
The benchmark and selection of superior articles (hot articles and prestigious articles) is the Thomson Reuters Science Foundation (ESI), one of the ISI products. In this section, articles that have received the most citations over the past two years are sometimes referred to as hot articles.
 
Islamic World Science Citation Center ISC annually announces the list of articles of the highest percentage of the country extracted from ESI.

http://isc.gov.ir/toppaper/toppercent.htm