Perhaps you should try some spelling variations:
te sach » toc sach
hieu su » hieu sau, tieu su, hieu so
dau cua » dai cua, day cua, cau cua
va danh » va dinh, va hanh, dia danh
cao hoi » cau hoi, co hoi, cao hoc
hieu vu » hieu va, hieu ve, dieu vu
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
va dan » ca dan, va dao, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach y nang cao hoi. ((hieu vu) OR (hieu su)) cham soc ((va danh) or (va dan)) dau cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang cao hoi. ((hieu vu) OR (hieu su)) cham soc ((va danh) OR (va dan)) dau cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y nang cao hoi. ((hieu vu) OR (hieu su)) cham soc ((va danh) or (va dan)) dau cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach y nang cao hoi. ((hieu vu) OR (hieu su)) cham soc ((va danh) or (va dan)) dau cua tre*.