Perhaps you should try some spelling variations:
va thieu » va thiet, va hieu, va tieu
hanh vai » hanh vi, hanh va, hanh tai
thu sach » thuat sach, thuoc sach, thu hoach
nang mai » nang ma, nang tai, lang mai
tu sach » su sach, te sach, tu cach
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ve chat » va chat, van chat
xuc va » duc va, tuc va, xac va
luc va » duc va, tuc va, loc va
vai va » mai va, dai va, hai va

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) OR (thu sach)) ky nang mai hoi. hieu ve chat ((xuc va) or (luc va)) hanh vai va thieu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang mai hoi. hieu ve chat ((xuc va) OR (luc va)) hanh vai va thieu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) ky nang mai hoi. hieu ve chat ((xuc va) or (luc va)) hanh vai va thieu".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) ky nang mai hoi. hieu ve chat ((xuc va) or (luc va)) hanh vai va thieu*.