Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
nang mai » nang ma, nang tai, lang mai
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
van hanh » van thanh, ban hanh, van anh
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
mai hoi » mai khoi, dai hoi, lai hoi
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 mai hoi. hieu hien ((cac nuoc) or (cam xuc)) van hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang mai hoi. hieu hien ((cac nuoc) OR (cam xuc)) van hanh vi cua viet.
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang mai hoi. hieu hien ((cac nuoc) or (cam xuc)) van hanh vi cua viet*.