Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
hanh di » hanh vi, hanh de, hang di
dat van » dao van, dat va, dam van
cac dat » cac dan, cai dat, cac dai
hieu va » lieu va, hieu qua
hieu ve » hieu van
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
ma hoi » mai hoi, xa hoi, me hoi
di cua » dai cua, doi cua, de 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 ty nang ((ma hoi) OR (ma hoa)). ((hieu ve) or (hieu va)) cac dat van hanh di cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang ((ma hoi) OR (ma hoa)). ((hieu ve) OR (hieu va)) cac dat van hanh di cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty nang ((ma hoi) OR (ma hoa)). ((hieu ve) or (hieu va)) cac dat van hanh di cua vat".
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang ((ma hoi) OR (ma hoa)). ((hieu ve) or (hieu va)) cac dat van hanh di cua vat*.