Perhaps you should try some spelling variations:
mai khoi » mai khoa, cac khoi, dai khoa
hanh vai » hanh vi, hanh va, hanh tai
tai khoa » da khoa, noi khoa
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
vai cuu » vai cua
va hanh » van hanh, va thanh, va danh
cam luc » cam xuc, cau luc
cuu tre » cua tre, cau tren, cau treo
sach ky » sac ky, sach y, sach ty
hieu ve » hieu van
ky sang » ky nang, ky dang, ky tang
luc va » duc va, tuc va, loc va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky sang ((mai khoi) OR (tai khoa)). ((hieu ve) or (hieu va)) cam luc va hanh vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky sang ((mai khoi) OR (tai khoa)). ((hieu ve) OR (hieu va)) cam luc va hanh vai cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky sang ((mai khoi) OR (tai khoa)). ((hieu ve) or (hieu va)) cam luc va hanh vai cuu tre*".