Perhaps you should try some spelling variations:
ban hoang » ban hang, van hoang, quan hoang
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
hoang te » hoang de, hoang tu, hoang le
nam duc » nam duoc, pham duc, nam thuc
duc ban » duc tan, duc van, dua ban
cua tre » cuu tre, cua triet, dua tren
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ((tu nano) or (truc nano)) xa hoi. hieu van nam duc ban hoang te ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((tu nano) OR (truc nano)) xa hoi. hieu van nam duc ban hoang te ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((tu nano) or (truc nano)) xa hoi. hieu van nam duc ban hoang te ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: thu sach ((tu nano) or (truc nano)) xa hoi. hieu van nam duc ban hoang te ((cua tre) OR (cua te))*.