Perhaps you should try some spelling variations:
thuat thuc » thuat thuy, thuyet thuc, thuc thuc
hanh vai » hanh vi, hanh va, hanh tai
hieu van » hieu va, thien van, lieu va
te sach » toc sach
ty tang » tay tang, ty hang, ky tang
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va
vai va » mai va, dai va, hai va
ma hoi » mai hoi, xa hoi, ma hoa
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ((ty tang) OR (ty xang)) ma hoi. ((hieu ve) or (hieu van)) thuat thuc va hanh vai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((ty tang) OR (ty xang)) ma hoi. ((hieu ve) OR (hieu van)) thuat thuc va hanh vai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((ty tang) OR (ty xang)) ma hoi. ((hieu ve) or (hieu van)) thuat thuc va hanh vai va thiet".
• Adding a wildcard symbol may retrieve word variants: te sach ((ty tang) OR (ty xang)) ma hoi. ((hieu ve) or (hieu van)) thuat thuc va hanh vai va thiet*.