Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
hanh hai » thanh hai, nhanh hai, hang hai
dua ban » dia ban, cua ban, qua ban
duc ban » duc tan, duc van, duc man
so sach » so sanh, bo sach, co sach
hieu ve » hieu va, hieu van
ky dang » ky nang, ky danh
ky tang » ky nang, kho tang, ky trong
ve cam » ve cham, ve cac, va cam
hai va » hai van, thai va, hoi va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ((ky tang) or (ky dang)) xa hoi. hieu ve cam ((duc ban) OR (dua ban)) hanh hai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((ky tang) OR (ky dang)) xa hoi. hieu ve cam ((duc ban) OR (dua ban)) hanh hai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((ky tang) or (ky dang)) xa hoi. hieu ve cam ((duc ban) OR (dua ban)) hanh hai va triet".
• Adding a wildcard symbol may retrieve word variants: so sach ((ky tang) or (ky dang)) xa hoi. hieu ve cam ((duc ban) OR (dua ban)) hanh hai va triet*.