Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
cau tren » cu tren, ca tren, cau treo
hanh vai » hanh vi, hanh va, hanh tai
mai khoi » mai khoa, tai khoa, cac khoi
va hanh » van hanh, va thanh, va danh
so sach » so sanh, bo sach, co sach
ky tang » ky nang, ky dang, kho tang
ky sang » ky nang, ky dang, duy sang
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam
xuc va » duc va, tuc va, luc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ((ky sang) or (ky tang)) mai khoi. hieu ve cam xuc va hanh vai ((cau tren) OR (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((ky sang) OR (ky tang)) mai khoi. hieu ve cam xuc va hanh vai ((cau tren) OR (dau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((ky sang) or (ky tang)) mai khoi. hieu ve cam xuc va hanh vai ((cau tren) OR (dau tren))".
• Adding a wildcard symbol may retrieve word variants: so sach ((ky sang) or (ky tang)) mai khoi. hieu ve cam xuc va hanh vai ((cau tren) OR (dau tren))*.