Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh dai » hanh tai, hanh dao, vanh dai
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
truc va » thuc va, thuc vat, trung va
cua tre » cua te, cuu tre, cua triet
loc va » hoc va, luc va

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 nang xa hoi. hieu van nam ((((duc va) or (loc va))) or (truc va)) hanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang xa hoi. hieu van nam ((((duc va) OR (loc va))) OR (truc va)) hanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang xa hoi. hieu van nam ((((duc va) or (loc va))) or (truc va)) hanh dai cua tre*.