Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
hoc viet » hoc hien
mai khoi » mai khoa, tai khoa, cac khoi
lai roi » lai hoi, loi roi
cach tu » cach thuc
tu nang » tru nang, tu nong, tu nano
cac duc » cao duc, cac dac, cac nuoc
va danh » va dinh, va dan, va hanh
danh vi » hanh vi, dinh vi, danh di
tu cach » tu cac
vi hoc » li hoc, va hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu cach tu nang ((mai khoi) or (lai roi)). hieu hien ((cac duc) or (cac du)) va danh vi hoc viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cach tu nang ((mai khoi) OR (lai roi)). hieu hien ((cac duc) OR (cac du)) va danh vi hoc viet.
• Adding a wildcard symbol may retrieve word variants: tu cach tu nang ((mai khoi) or (lai roi)). hieu hien ((cac duc) or (cac du)) va danh vi hoc viet*.