Rule 701.23f

If searching a zone is replaced with searching a portion of that zone, any other instructions that refer to searching the zone still apply. Any abilities that trigger on a library being searched will trigger. Example: Aven Mindcensor says, in part, “If an opponent would search a library, that player searches the top four cards of that library instead.” Veteran Explorer says “When this creature dies, each player may search their library for up to two basic land cards, put them onto the battlefield, then shuffle.” An opponent who searched the top four cards of their library because of Veteran Explorer’s ability would shuffle the entire library.