The search is using a "fuzzy" approach, allowing up to 3 character mismatches (depending on the word's length). And every word in a search query is treated as a separate keyword. The words search only applies to report names and descriptions.
If you would like to search for a specific word, disallowing any mismatches, or a specific phrase of two words, you can use quotes:
"my beautiful query"
You can also exclude a word from the result by adding a minus sign before the word
-bad
The search can also accept special commands in a format !command:value1,value2...
The full list of commands:
cat - use filters of the specified category. Accepts only one argument, does nothing if the category does not exist.region - specify the list of regions you want to see. It requires numerical IDs from the Metadata, but you can also use special keywords: na, us, sa, peru, brazil, sea, korea, dubai, india, china, japan, asia, eu, europe, eue, eueast, cis, russia, euw, euwest, meta, africa, australia. But if you need a specific region you should use numerical ID of this region (some region keywords refer to a whole group instead of one specific ID).team - specify the list of teams (by ID) you want to see in a reportplayers - specify the list of players (by ID) you want to see in a reportlid - specify League ID valuetag-has - find a substring in a report's tagmid-from - find reports with matches starting from specified valuemid-to - find reports with matches played before from specified valuedate-from - find reports with dates starting from specified value (UNIX timestamp)date-to - find reports with dates before from specified value (UNIX timestamp)type - specify report type. Can be either tvt (teams, competitive) or pvp (players, ranked). Aside from that, words starting with "rank" are treated as an alias to this command with "pvp" value (if you're looking for a specific word, please use quotes)matches-less - find reports with the number of matches played more than valuematches-more - find reports with the number of matches played less than valuedays-less - find reports with the number of activity days more than valuedays-more - find reports with the number of activity days less than valuepatch - find reports played on this patchpatch-from - find reports played on patches after specified onepatch-to - find reports played on patches before specified one