Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
cac toi » cac thoi
cua tre » cua te, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
cuu tre » cau tren, cau treo
cac toc » cac nuoc, cac thoi
lang xa » lang ha, dang xay, lang van
y lang » o lang, _ lang, tay lang

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

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