Perhaps you should try some spelling variations:
thay nuoc » tham nuoc, tray nuoc, thoat nuoc
hieu van » hieu va, thien van, lieu va
van thay » van tham, van than, van thac
hanh lai » hanh lam, hanh tai, thanh lap
cua tre » cua te, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
te sach » toc sach
cao hoi » cau hoi, co hoi, cao hoc
ty hang » ly hang, ty xang, thi hang
ty nang » ky nang, ty xang, ly nang
cuu tre » cau tren, cau treo

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