Perhaps you should try some spelling variations:
dieu hien » dieu khien, dieu kien, bieu hien
hieu hien » bieu hien, chieu chien, dieu khien
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
cua viet » ca viet, hoa viet, cua vat
nang mai » nang ma, nang tai, lang mai
mai hoi » mai khoi, dai hoi, lai hoi
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
van anh » van thanh, tuan anh, van minh
te sach » toc 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: te sach ty nang mai hoi. ((hieu hien) OR (dieu hien)) ((cac nuoc) or (cam xuc)) van anh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty nang mai hoi. ((hieu hien) OR (dieu hien)) ((cac nuoc) OR (cam xuc)) van anh vi cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty nang mai hoi. ((hieu hien) OR (dieu hien)) ((cac nuoc) or (cam xuc)) van anh vi cua viet".
• Adding a wildcard symbol may retrieve word variants: te sach ty nang mai hoi. ((hieu hien) OR (dieu hien)) ((cac nuoc) or (cam xuc)) van anh vi cua viet*.