Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
hanh dai » hanh tai, hanh dao, vanh dai
thuc dan » thuc hanh, hoc dan, thuc vat
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
ky sang » ky dang, ky tang, duy sang
ve cam » ve cham, ve cac, va cam
ma hoi » mai hoi, xa hoi, ma hoa
tuc va » thuc va, truc va, tuc xa
dai va » mai va

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 sang) or (ky nang)) ma hoi. hieu ve cam ((tuc va) or (thuc dan)) hanh dai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky sang) OR (ky nang)) ma hoi. hieu ve cam ((tuc va) OR (thuc dan)) hanh dai va triet.
• Adding a wildcard symbol may retrieve word variants: su sach ((ky sang) or (ky nang)) ma hoi. hieu ve cam ((tuc va) or (thuc dan)) hanh dai va triet*.