Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
qua ban » cua ban, qua quan
vai cau » va cau, van cau, lai chau
vai cac » va cac, tai cac, voi cac
nam qua » nam quan, nam cua, nam mua
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, me hoi

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