Perhaps you should try some spelling variations:
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
hanh tai » thanh tai, hang tai, han tai
hanh dai » hanh dao, vanh dai, thanh dat
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
van cac » van hac, van cau, van bac
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cuu tre, cua triet
me hoi » le hoi

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 ty xang ((me hoi) or (xa hoi)). hieu van cac nuoc va ((hanh dai) OR (hanh tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty xang ((me hoi) OR (xa hoi)). hieu van cac nuoc va ((hanh dai) OR (hanh tai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty xang ((me hoi) or (xa hoi)). hieu van cac nuoc va ((hanh dai) OR (hanh tai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty xang ((me hoi) or (xa hoi)). hieu van cac nuoc va ((hanh dai) OR (hanh tai)) cua tre*.