Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
thuc day » thuc dan
hanh tai » thanh tai, hang tai, han tai
va triet » va thiet, va trien, ve triet
sach ky » sac ky, sach y, sach ty
ky sang » ky nang, ky dang, ky tang
sang ma » tang ma, nang ma, sang tao
hieu vi » hieu voi, hieu va, hieu ve
ma hoi » mai hoi, xa hoi, ma hoa
tai va » thai va, mai va, tri va

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ky sang ma hoi. hieu vi pham ((thuc day) OR (thuc vat)) hanh tai va triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ky sang ma hoi. hieu vi pham ((thuc day) OR (thuc vat)) hanh tai va triet".
• Adding a wildcard symbol may retrieve word variants: doc sach ky sang ma hoi. hieu vi pham ((thuc day) OR (thuc vat)) hanh tai va triet*.