Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
dinh tri » chinh tri
tri cau » tri cac, tri dau, trinh cau
va dinh » van dinh, va kinh, va tinh
nam duc » nam duoc, pham duc, nam thuc
hieu va » lieu va, hieu qua
va nam » van nam, ha nam, va nay
ma hoi » mai hoi, ma hoa, me hoi
sac ky » cac ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sai ky) OR (sac ky)) nang ((ma hoi) or (xa hoi)). hieu va nam duc va dinh tri cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sai ky) OR (sac ky)) nang ((ma hoi) OR (xa hoi)). hieu va nam duc va dinh tri cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sai ky) OR (sac ky)) nang ((ma hoi) or (xa hoi)). hieu va nam duc va dinh tri cau tren".
• Adding a wildcard symbol may retrieve word variants: te ((sai ky) OR (sac ky)) nang ((ma hoi) or (xa hoi)). hieu va nam duc va dinh tri cau tren*.