Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
sach van » sach han, sach va, bach van
van nang » van quang, van ban, van dong
cam truc » cau truc, nam truc, lam truoc
cua tre » cua te, cuu tre, dua tren
hanh ve » hanh vi, hanh va, hanh kem
hanh de » hanh kem
su sach » so sach, vu sach
truc va » thuc va, thuc vat, trung va
hieu va » lieu va, hieu qua
va cam » va cham, va cac, va cao
nang o » nang co, nang ho, nang ro
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: su sach van nang o hoi. hieu va cam truc va ((hanh de) or (hanh ve)) ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach van nang o hoi. hieu va cam truc va ((hanh de) OR (hanh ve)) ((cua tre) OR (cua triet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach van nang o hoi. hieu va cam truc va ((hanh de) or (hanh ve)) ((cua tre) OR (cua triet))*".