Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
doc sach » toc sach, nuoc sach, dac sac
cua tre » cua te, cua triet, dua tren
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
cac luc » cau luc, coc luc, cac nuoc
lang xa » lang ha, dang xay, lang van
cuu tre » cau tren, cau treo
luc va » duc va, tuc va, loc va
v lang » va lang, o lang, _ lang

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