Perhaps you should try some spelling variations:
mai khoi » mai khoa, tai khoa, dai khoa
hanh tai » thanh tai, hang tai, han tai
cac khoi » cac thoi, cac khoan, cach thoi
su sach » so sach, vu sach
tai cuu » tai cuc, tai buu, tai cua
hieu ve » hieu va, hieu van
ky lang » ky nang, ky dang, ky tang
sach ky » sac ky, sach y, sach ty
cuu tre » cua tre, cau tren, cau treo
ve cam » ve cham, ve cac, va cam
xuc va » duc va, luc va, xac va
tuc va » thuc va, truc va, tuc xa

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 lang ((mai khoi) or (cac khoi)). hieu ve cam ((xuc va) OR (tuc va)) hanh tai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky lang ((mai khoi) OR (cac khoi)). hieu ve cam ((xuc va) OR (tuc va)) hanh tai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky lang ((mai khoi) or (cac khoi)). hieu ve cam ((xuc va) OR (tuc va)) hanh tai cuu tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky lang ((mai khoi) or (cac khoi)). hieu ve cam ((xuc va) OR (tuc va)) hanh tai cuu tre*.