Perhaps you should try some spelling variations:
thien van » thi van
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, lieu va, hieu ve
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
ma hoi » mai hoi, ma hoa, me hoi
dan va » doan va, dan ca, ban va
vi cua » vai cua, di cua

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 ((ma hoi) or (xa hoi)). ((hieu van) OR (thien van)) cac dan va hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((ma hoi) OR (xa hoi)). ((hieu van) OR (thien van)) cac dan va hanh vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ((ma hoi) or (xa hoi)). ((hieu van) OR (thien van)) cac dan va hanh vi cua vat".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((ma hoi) or (xa hoi)). ((hieu van) OR (thien van)) cac dan va hanh vi cua vat*.