Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
cua viet » ca viet, hoa viet, cua vat
tai khoi » tai khoa, mai khoi, tao khoi
dai hai » dai han, dai hoi, dai tai
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
van anh » van thanh, tuan anh, van minh
tu sach » thu sach, su sach, te sach
anh vi » hanh vi, anh va, anh ve
vi cua » vai cua, di cua

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 ty nang ((tai khoi) or (dai hai)). hieu hien ((cac nuoc) or (cam xuc)) van anh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((tai khoi) OR (dai hai)). hieu hien ((cac nuoc) OR (cam xuc)) van anh vi cua viet.
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((tai khoi) or (dai hai)). hieu hien ((cac nuoc) or (cam xuc)) van anh vi cua viet*.