Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
ban thanh » ban hanh, ban hang
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
nam dua » nam da, nam cua, nam mua
dua ban » dia ban, cua ban, qua ban
cuu tre » cau tren, cau treo
cua tre » cua te, cua triet, dua tren
y nang » ky nang, ly nang, v nang

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 y nang ((xa hoi) or (ma hoa)). hieu van nam dua ban thanh van ((cuu tre) OR (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y nang ((xa hoi) OR (ma hoa)). hieu van nam dua ban thanh van ((cuu tre) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y nang ((xa hoi) or (ma hoa)). hieu van nam dua ban thanh van ((cuu tre) OR (cua tre))".
• Adding a wildcard symbol may retrieve word variants: thu sach y nang ((xa hoi) or (ma hoa)). hieu van nam dua ban thanh van ((cuu tre) OR (cua tre))*.