Perhaps you should try some spelling variations:
dau tieng » dau tien, cau tieng, day tieng
va trinh » van trinh, va tinh, lap trinh
trinh vi » trinh va, trinh ve, trinh viet
dau tren » dau tien, dat tren, dau trong
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
cam duc » cam xuc, cao duc, pham duc
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ho, nang ro
ve cam » ve cham, ve cac, va cam
o hoi » co hoi, o hoc, o hai

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang o hoi. hieu ve cam duc va trinh vi ((cua tre) OR (((dau tren) OR (dau tieng))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang o hoi. hieu ve cam duc va trinh vi ((cua tre) or (((dau tren) OR (dau tieng))))~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang o hoi. hieu ve cam duc va trinh vi ((cua tre) or (((dau tren) OR (dau tieng))))*.