Perhaps you should try some spelling variations:
khoai lang » hoa lang, hoi lang, khoa dang
sach khoai » bach khoa, sach hoi
toc sach » hoc sach, doc sach, thuoc sach
hanh vai » hanh vi, hanh tai, hanh van
va triet » va thiet, va trien, ve triet
hieu ve » hieu va, hieu van
cac tuc » cac toc, cac tu, cac tac
lang xa » lang ha, dang xay, lang van
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach khoai lang xa hoi. hieu ve cac tuc va ((hanh vai) or (hanh va)) ((cua tre) or (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach khoai lang xa hoi. hieu ve cac tuc va ((hanh vai) OR (hanh va)) ((cua tre) OR (va triet)).
• Adding a wildcard symbol may retrieve word variants: toc sach khoai lang xa hoi. hieu ve cac tuc va ((hanh vai) or (hanh va)) ((cua tre) or (va triet))*.