Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
cua viet » hoa viet, cua vat, cua dieu
nang cai » nang cao, nang tai, nang cap
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
hanh di » hanh vi, hanh de, hang di
ca viet » va viet, co viet, hoa viet
sach ty » sach y, sach tu, sach thu
cac xuc » cac nuoc, chat xuc, cac cuoc
cai hoi » cau hoi, dai hoi, cai hoa
ty nang » ky nang, ty xang, ty hang

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 cai hoi. hieu hien ((cac xuc) or (cam xuc)) van hanh di ((cua viet) or (ca viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang cai hoi. hieu hien ((cac xuc) OR (cam xuc)) van hanh di ((cua viet) OR (ca viet)).
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang cai hoi. hieu hien ((cac xuc) or (cam xuc)) van hanh di ((cua viet) or (ca viet))*.