Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
cau tren » cu tren, dau tren, ca tren
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, cao hoc, tao hoi
van cam » van nam, van lam, van cau
cam duc » cam xuc, cao duc, pham duc
cuu tre » cua tre, cau treo
co hoi » co hoc, co loi

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang ((cao hoi) OR (co hoi)). hieu van cam duc va thanh dai ((cuu tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((cao hoi) OR (co hoi)). hieu van cam duc va thanh dai ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((cao hoi) OR (co hoi)). hieu van cam duc va thanh dai ((cuu tre) or (cau tren))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((cao hoi) OR (co hoi)). hieu van cam duc va thanh dai ((cuu tre) or (cau tren))*.