Perhaps you should try some spelling variations:
hieu hien » bieu hien, chieu chien, dieu khien
dieu hien » dieu khien, dieu kien, bieu hien
van hanh » van thanh, ban hanh, van anh
nang mai » nang ma, nang tai, lang mai
cac xuc » cac nuoc, chat xuc, cac cuoc
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
mai hoi » mai khoi, dai hoi, lai hoi
ty nang » ky nang, ty xang, ty hang
ca viet » va viet, co viet, hoa viet
vi ca » vit ca, li ca, va ca

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 mai hoi. ((hieu hien) OR (dieu hien)) ((cac xuc) or (cam xuc)) van hanh vi ca viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang mai hoi. ((hieu hien) OR (dieu hien)) ((cac xuc) OR (cam xuc)) van hanh vi ca viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang mai hoi. ((hieu hien) OR (dieu hien)) ((cac xuc) or (cam xuc)) van hanh vi ca viet".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang mai hoi. ((hieu hien) OR (dieu hien)) ((cac xuc) or (cam xuc)) van hanh vi ca viet*.