Perhaps you should try some spelling variations:
danh thai » anh thai, dang thai, dinh thai
thai cua » than cua, tai cuc, tri cua
qua cham » qua cac, va cham, qua cua
su sach » so sach, vu sach
qua hai » qua hoat
va danh » va dinh, va dan, va hanh
cua tre » cua te, cuu tre, cua triet
cai hoi » dai hoi, cai hoa, lai hoi
y nang » ky nang, ly nang, v nang
soc va » hoc va, loc va, doc va

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 nang ((cai hoi) or (cau hoi)). hieu ((qua cham) OR (qua hai)) soc va danh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang ((cai hoi) OR (cau hoi)). hieu ((qua cham) OR (qua hai)) soc va danh thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang ((cai hoi) or (cau hoi)). hieu ((qua cham) OR (qua hai)) soc va danh thai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach y nang ((cai hoi) or (cau hoi)). hieu ((qua cham) OR (qua hai)) soc va danh thai cua tre*.