Perhaps you should try some spelling variations:
dua tren » dung tren
va thanh » gia thanh, ban thanh, va tinh
va hanh » van hanh, va danh, ban hanh
cu tren » tu tren
sach ky » sac ky, sach y, sach ty
su sach » so sach, vu sach
hieu te » hieu ve, hien te, hieu he
ban co » ban do, san co
te ban » te bao

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang x ho. hieu te ban co ((va hanh) or (va thanh)) vi ((cu tren) OR (dua tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang x ho. hieu te ban co ((va hanh) OR (va thanh)) vi ((cu tren) OR (dua tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang x ho. hieu te ban co ((va hanh) or (va thanh)) vi ((cu tren) OR (dua tren))".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang x ho. hieu te ban co ((va hanh) or (va thanh)) vi ((cu tren) OR (dua tren))*.