Perhaps you should try some spelling variations:
lang dai » lang hai, lang mai, lang chai
hanh vai » hanh vi, hanh tai, hanh van
hieu van » thien van, lieu va, hieu ve
tu sach » thu sach, su sach, te sach
cam duc » cam xuc, cao duc, pham duc
hanh va » hang va, hanh vi
cuu tre » cua tre, cau tren, cau treo
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
dai hoi » dai hoc, dai hai, dai moi
ky lang » ky nang, ky dang, ky tang

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 ky lang dai hoi. ((hieu van) OR (hieu va)) cam duc va ((hanh vai) or (hanh va)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky lang dai hoi. ((hieu van) OR (hieu va)) cam duc va ((hanh vai) OR (hanh va)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky lang dai hoi. ((hieu van) OR (hieu va)) cam duc va ((hanh vai) or (hanh va)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky lang dai hoi. ((hieu van) OR (hieu va)) cam duc va ((hanh vai) or (hanh va)) cuu tre*.