Perhaps you should try some spelling variations:
sach thi » sach thu, sach tai, sach thieu
thi nang » thi cong, ki nang, thi hanh
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
hanh va » hang va, hanh vi
vuc van » duc van, luc van, thuc van
cac vuc » cac nuoc, cac vung, cac cuoc
hieu ve » hieu va
cua tre » cua te, cuu tre, cua triet

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 thi nang x ho. ((hieu ve) or (hieu van)) cac vuc van ((anh viet) or (hanh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thi nang x ho. ((hieu ve) OR (hieu van)) cac vuc van ((anh viet) OR (hanh va)) cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach thi nang x ho. ((hieu ve) or (hieu van)) cac vuc van ((anh viet) or (hanh va)) cua tre*.