Try to substitute your like with this:
like "*" & tblsearchengine07.parolachiave & "*"
Update.
If you are not interested in storing your search values in a table, you can simply create your query string by reading textBox.value like this:
Dim sql as string
sql = "update yourtablename set yourfiled = true where yourconditionfield like '*" & textboxname.value & "*'"
Docmd.runsql sql