Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
thuc day » thuc dan
sach ky » sac ky, sach y, sach ty
hanh di » hanh vi, hanh de, hang di
hieu va » lieu va, hieu qua
hieu ve » hieu van
cao hoi » cau hoi, co hoi, cao hoc
di cua » dai cua, doi cua, de cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang cao hoi. ((hieu ve) OR (hieu va)) pham ((thuc day) or (thuc vat)) hanh di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang cao hoi. ((hieu ve) OR (hieu va)) pham ((thuc day) OR (thuc vat)) hanh di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang cao hoi. ((hieu ve) OR (hieu va)) pham ((thuc day) or (thuc vat)) hanh di cua te".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang cao hoi. ((hieu ve) OR (hieu va)) pham ((thuc day) or (thuc vat)) hanh di cua te*.