Perhaps you should try some spelling variations:
tru nang » tri nang, truc nano, thi nang
tra nang » thi nang, kha nang, da nang
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
hanh de » hanh ve, hanh kem
hanh di » hanh vi, hang di, danh di
van cam » van nam, van lam, van cau
cam cua » ca cua, nam cua, cau cua
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 ((tru nang) or (tra nang)) xa hoi. hieu van cam cua ban ((hanh di) OR (hanh de)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((tru nang) OR (tra nang)) xa hoi. hieu van cam cua ban ((hanh di) OR (hanh de)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((tru nang) or (tra nang)) xa hoi. hieu van cam cua ban ((hanh di) OR (hanh de)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((tru nang) or (tra nang)) xa hoi. hieu van cam cua ban ((hanh di) OR (hanh de)) cua tre*.