Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hai khoi » mai khoi, thai khoa, chai khoa
tai khoi » tai khoa, mai khoi, tao khoi
hanh tai » thanh tai, hang tai, han tai
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau treo
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
ky lang » ky nang, ky dang, ky tang
xuc va » duc va, tuc va, luc va
ve cam » ve cham, ve cac, va cam

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