Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
cua triet » su triet, va triet
hanh vai » hanh vi, hanh va, hanh tai
cua viet » ca viet, hoa viet, cua vat
hieu va » lieu va
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
nang ma » tang ma, sang ma, nang cao
cac lo » cac lop, cac co, cac bo
ma hoi » mai hoi, xa hoi, ma hoa
lo va » lo van, lao va, ly va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach ky nang ma hoi. ((hieu va) or (hieu qua)) cac lo va hanh vai ((cua triet) OR (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ky nang ma hoi. ((hieu va) OR (hieu qua)) cac lo va hanh vai ((cua triet) OR (cua viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ky nang ma hoi. ((hieu va) or (hieu qua)) cac lo va hanh vai ((cua triet) OR (cua viet))".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ky nang ma hoi. ((hieu va) or (hieu qua)) cac lo va hanh vai ((cua triet) OR (cua viet))*.