Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
sach o » sach lo, sac o, sach y
o lang » hoa lang, hoi lang
luc va » tuc va, loc va

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

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