Perhaps you should try some spelling variations:
voi hoat » toi hoat, doi hoat, vo hoat
nang mai » nang ma, nang tai, lang mai
van hanh » van thanh, ban hanh, van anh
cac xuc » cam xuc, cac nuoc, chat xuc
voi hoa » voi khoa, boi hoa, voi ho
xuc van » duc van, luc van, vuc van
su sach » so sach
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
vu sach » vu bach, vu khach
y nang » ky nang, ly nang, v nang
ve cac » va cac, vien cac

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) OR (vu sach)) y nang mai hoi. hieu ve 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) OR (vu sach)) y nang mai hoi. hieu ve 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) OR (vu sach)) y nang mai hoi. hieu ve cac xuc van hanh ((voi hoa) or (voi hoat)) viet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) OR (vu sach)) y nang mai hoi. hieu ve cac xuc van hanh ((voi hoa) or (voi hoat)) viet*.