Perhaps you should try some spelling variations:
cam thuyet » bai thuyet, bam huyet, cac tuyet
sang tai » hang tai, sang tao, tang tai
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
va sang » van sang, vua sang, va nang
cua tre » cuu tre, cua triet, dua tren
y nang » ky nang, ly nang, v nang
va cam » va cham, va cac, va cao
cua te » cua tu
o hoi » co hoi, o hoc, o hai

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 y nang ((o hoi) or (xa hoi)). hieu va cam thuyet va sang tai ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((o hoi) OR (xa hoi)). hieu va cam thuyet va sang tai ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((o hoi) or (xa hoi)). hieu va cam thuyet va sang tai ((cua tre) or (cua te))*.