Perhaps you should try some spelling variations:
hieu quan » lieu quan, thien quan, lien quan
cao sang » cao dang, cao tang, cao bang
nam thuc » nam thuoc, am thuc, nam thu
cua viet » ca viet, hoa viet, cua vat
lo sang » lam sang, luc sang, lee sang
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
tu sach » thu sach, su sach, te sach
ma hoi » mai hoi, xa hoi, ma hoa
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((lo sang) or (cao sang)) ma hoi. ((hieu quan) or (hieu qua)) nam thuc va hanh di cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((lo sang) OR (cao sang)) ma hoi. ((hieu quan) OR (hieu qua)) nam thuc va hanh di cua viet.
• Adding a wildcard symbol may retrieve word variants: tu sach ((lo sang) or (cao sang)) ma hoi. ((hieu quan) or (hieu qua)) nam thuc va hanh di cua viet*.