One source that provides scores for boys basketball tournaments throughout the United States, especially at the high school level, is MaxPreps. Other options include visiting the website for the team's basketball league or the team's state's high school athletic association website.
MaxPreps includes a section for high school boys basketball scores and schedules, and it allows users to sort by state, division, league or section to see scores from the past 2 weeks.
Users seeking scores for older tournaments may want to visit their state's high school athletic association website since it may list results for the past several years and include more detailed information about the divisions.
The sports section of the school's team website may include detailed tournament information for at least the current school year, and this kind of website may also offer detailed stats for each part of the tournament.