Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
cao hoat » cac hoat, co hoat, cao chat
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
va hang » van hang, va nang, va lang
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
cua tu » cua tuc, cua su, cua cu
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: ((tu sach) OR (su sach)) y nang cao hoat. hieu viec cua tu va hang va cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) y nang cao hoat. hieu viec cua tu va hang va cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) y nang cao hoat. hieu viec cua tu va hang va cua tre*.