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
cac luc » cau luc, coc luc, cac nuoc
hanh di » hanh de, hang di, danh di
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
luc va » duc 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 _ lang xa hoi. hieu va cac luc va ((hanh di) or (hanh vi)) ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach _ lang xa hoi. hieu va cac luc va ((hanh di) OR (hanh vi)) ((cua tre) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: hoc sach _ lang xa hoi. hieu va cac luc va ((hanh di) or (hanh vi)) ((cua tre) or (cuu tre))*.