Perhaps you should try some spelling variations:
sang mai » sang ma, sang tai, lang mai
thuc day » thuc dan, thuc vat
sach ky » sac ky, sach y, sach ty
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ky sang » ky nang, ky dang, ky tang
ve cam » ve cham, ve cac, va cam
dao va » dao van, tao va, cao va
tuc va » thuc va, truc va, tuc xa
do va » do van, so 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 mai hoi. hieu ve cam ((tuc va) or (thuc day)) hanh ((dao va) or (do va)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky sang mai hoi. hieu ve cam ((tuc va) OR (thuc day)) hanh ((dao va) OR (do va)) triet.
• Adding a wildcard symbol may retrieve word variants: su sach ky sang mai hoi. hieu ve cam ((tuc va) or (thuc day)) hanh ((dao va) or (do va)) triet*.