UMLS search types

[Ivelina Nikolova]

Dear corpora members,

I'm trying to find out more about the matching algorithms that UMLS UTS
uses for searching in the database. They are the following but I
couldn't really get to some detailed explanation what they stand for. Is
anyone aware of these types?

Word,
Approximate match
Exact match
Normalized string
Normalized word
Right truncation
Left truncation

Thanks!
Ivelina