Perhaps you should try some spelling variations:
cao hoat » co hoat, cao chat, dan hoat
vien cac » vien bach, vien dai, vien da
viec cac » viec cua, viec lam, viec va
cac hoat » cac khoan, cac thuat, cac hop
va hang » van hang, va nang, va lang
su sach » so sach, vu sach
ly nang » ky nang, ly hang, ly vang
sach ly » sach y, sach lo, sach ty
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua

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 ly nang ((cao hoat) OR (cac hoat)). hieu ((viec cac) or (vien cac)) tu va hang va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly nang ((cao hoat) OR (cac hoat)). hieu ((viec cac) OR (vien cac)) tu va hang va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ly nang ((cao hoat) OR (cac hoat)). hieu ((viec cac) or (vien cac)) tu va hang va cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ly nang ((cao hoat) OR (cac hoat)). hieu ((viec cac) or (vien cac)) tu va hang va cua tre*.