Perhaps you should try some spelling variations:
thien van » thi van
tham nuoc » thay nuoc, thoat nuoc, nha nuoc
hieu van » hieu va, lieu va, hieu ve
hanh tai » thanh tai, hang tai, han tai
te sach » toc sach
cao hoi » cau hoi, co hoi, tao hoi
cao hoc » co hoc, cho hoc, chat hoc
va hanh » van hanh, va thanh, va danh
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
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: te sach y nang ((cao hoi) OR (cao hoc)). ((hieu van) or (thien van)) tham nuoc va hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang ((cao hoi) OR (cao hoc)). ((hieu van) OR (thien van)) tham nuoc va hanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y nang ((cao hoi) OR (cao hoc)). ((hieu van) or (thien van)) tham nuoc va hanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach y nang ((cao hoi) OR (cao hoc)). ((hieu van) or (thien van)) tham nuoc va hanh tai cua tre*.