Perhaps you should try some spelling variations:
ban hanh » ban hang
vien cac » vien bach, vien dai, gian cac
cua viet » ca viet, hoa viet, cua vat
nang ma » tang ma, sang ma, nang cao
sach ky » sach y, sach ty, sach kem
vien da » vien dai, hien dai
xuc ban » duc ban, cuc ban, quoc ban
ma hoi » mai hoi, xa hoi, ma hoa
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 hoi. hieu ((vien cac) or (vien da)) xuc ban 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 hoi. hieu ((vien cac) OR (vien da)) xuc ban 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 hoi. hieu ((vien cac) or (vien da)) xuc ban hanh vi cua viet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sac ky)) nang ma hoi. hieu ((vien cac) or (vien da)) xuc ban hanh vi cua viet*.