Perhaps you should try some spelling variations:
duc minh » duc anh
thu nang » thi nang, thu hang, thu bang
hanh tai » thanh tai, hang tai, han tai
hanh lai » hanh lam, thanh lap, thanh loi
hieu van » hieu va, thien van, lieu va
sach thu » sach thue, sach thieu, sach tham
tu sach » thu sach, su sach, te sach
hieu ve » hieu va
nang xa » nang x, lang xa, nang ma
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 thu nang xa hoi. ((hieu ve) or (hieu van)) pham duc minh ((hanh lai) or (hanh tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu nang xa hoi. ((hieu ve) OR (hieu van)) pham duc minh ((hanh lai) OR (hanh tai)) cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach thu nang xa hoi. ((hieu ve) or (hieu van)) pham duc minh ((hanh lai) or (hanh tai)) cua tre*.