Perhaps you should try some spelling variations:
hanh doi » thanh doi, hanh noi, hang doi
vat hanh » vat thanh, van hanh, va hanh
su sach » so sach
doi cua » dai cua, hoi cua
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
vu sach » vu bach, vu khach
v nang » va nang, vu nang, van nang
o hoc » co hoc, mo hoc, so hoc
x hoi » xa hoi, o hoi, x ho
va am » va lam, va cam
thuc » thu

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) or (vu sach)) v nang ((x hoi) or (o hoc)). hieu va am thuc vat hanh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) v nang ((x hoi) OR (o hoc)). hieu va am thuc vat hanh doi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) v nang ((x hoi) or (o hoc)). hieu va am thuc vat hanh doi cua tre*.