Perhaps you should try some spelling variations:
thien van » thi van
hanh dai » hanh tai, hanh dao, vanh dai
cham duc » pham duc, cham soc, pham duy
hieu van » hieu va, lieu va, hieu ve
sach thu » sach thue, sach thieu, sach tham
xang xa » lang xa, mang xa, ang xa
sach ty » sach y, sach tu, xach tay
va hanh » van hanh, va thanh, va danh
dai cuu » dai cua, dai huu
cuu tre » cua tre, cau tren, cau treo

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((sach ty) or (sach thu)) xang xa hoi. ((hieu van) or (thien van)) cham duc va hanh dai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((sach ty) OR (sach thu)) xang xa hoi. ((hieu van) OR (thien van)) cham duc va hanh dai cuu tre.
• Adding a wildcard symbol may retrieve word variants: doc ((sach ty) or (sach thu)) xang xa hoi. ((hieu van) or (thien van)) cham duc va hanh dai cuu tre*.