Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
ban hanh » ban hang
hieu van » hieu va, thien van, lieu va
hanh ke » hanh kem, thanh ke, hanh ky
duc ban » duc tan, duc van, dua ban
nam duc » nam duoc, pham duc, nam thuc
ky dang » ky nang, ky danh
te sach » toc sach
dang xa » dang xay, lang xa, dang ha
ke dau » ke cau, ke dan, ke dam

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((((tu cach) or (tu cac))) or (te sach)) ky dang xa hoi. hieu van nam duc ban hanh ke dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((tu cach) OR (tu cac))) OR (te sach)) ky dang xa hoi. hieu van nam duc ban hanh ke dau tren.
• Adding a wildcard symbol may retrieve word variants: ((((tu cach) or (tu cac))) or (te sach)) ky dang xa hoi. hieu van nam duc ban hanh ke dau tren*.