Perhaps you should try some spelling variations:
tham nuoc » thay nuoc, thoat nuoc, nha nuoc
hieu van » thien van, lieu va, hieu ve
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
va hanh » va thanh, va danh, ban hanh
lai cua » dai cua, hai cua, lai chau
cua tre » cua te, cuu tre, cua triet

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 ty nang cao hoi. ((hieu van) OR (hieu va)) tham nuoc ((va hanh) or (van hanh)) lai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty nang cao hoi. ((hieu van) OR (hieu va)) tham nuoc ((va hanh) OR (van hanh)) lai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty nang cao hoi. ((hieu van) OR (hieu va)) tham nuoc ((va hanh) or (van hanh)) lai cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ty nang cao hoi. ((hieu van) OR (hieu va)) tham nuoc ((va hanh) or (van hanh)) lai cua tre*.