-1
Looking at the json for the history of a match (eg. https://api.steampowered.com/IDOTA2Match_570/GetMatchHistory/V001/?format=json&key=5C27735910F8A755A2AFD0D9868BAD80&league_id=4442)
You have;
"total_results": 418,
"results_remaining": 318,
Seeing as the search only provides the first 100 res...