The easiest way is to do it like this

WHERE Oink.[System] like @System + '%'

ANDOink.Stratigrafie like @Stratigrafie + '%'

ANDOink.Ulozeni like @Ulozeni + '%'

AND Oink.DrEvid like @DrEvid + '%'

Or you can add it to the variables before the query if it's easier for you.