Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
cua viet » ca viet, hoa viet, cua vat
van hanh » van thanh, ban hanh, van anh
vien cac » vien bach, vien dai, vien da
sach ky » sach y, sach ty, sach kem
xuc van » duc van, luc van, xuc ban
cac xuc » cam xuc, cac nuoc, chat xuc
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
sac ky » cac ky, sai ky
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 ky) or (sac ky)) ((nang ma) OR (tang ma)) hoi. hieu vien cac xuc van hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) ((nang ma) OR (tang ma)) hoi. hieu vien cac xuc van hanh vi cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sac ky)) ((nang ma) OR (tang ma)) hoi. hieu vien cac xuc van hanh vi cua viet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sac ky)) ((nang ma) OR (tang ma)) hoi. hieu vien cac xuc van hanh vi cua viet*.