Perhaps you should try some spelling variations:
voi hoat » toi hoat, doi hoat, vo hoat
van hanh » van thanh, ban hanh, van anh
xuc van » duc van, luc van, vuc van
voi hoa » voi khoa, boi hoa, voi ho
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
hieu ve » hieu van
nang ma » tang ma, sang ma, nang cao
cac xuc » cam xuc, cac nuoc, chat xuc
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y nang ma hoi. ((hieu ve) OR (hieu va)) cac xuc van hanh ((voi hoa) or (voi hoat)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang ma hoi. ((hieu ve) OR (hieu va)) cac xuc van hanh ((voi hoa) OR (voi hoat)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang ma hoi. ((hieu ve) OR (hieu va)) cac xuc van hanh ((voi hoa) or (voi hoat)) viet".
• Adding a wildcard symbol may retrieve word variants: su sach y nang ma hoi. ((hieu ve) OR (hieu va)) cac xuc van hanh ((voi hoa) or (voi hoat)) viet*.