Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hanh vai » hanh vi, hanh va, hanh tai
hieu van » hieu va, thien van, lieu va
hieu ve » hieu va
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
vai cau » va cau, van cau, vai cac
tu sach » thu sach, su sach, te sach
xuc va » tuc va, luc va, xac va
x hoi » xa hoi, o hoi, x ho

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

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