Perhaps you should try some spelling variations:
tham nhung » thi nhung
sach tham » sach nha
hieu van » hieu va, thien van, lieu va
van tham » van thanh, van tuan, van chat
va triet » va trien, ve triet, cua triet
hanh lai » hanh lam, hanh tai, thanh lap
tan hanh » tan thanh, tang hanh, toan hanh
tham duc » pham duc, tham du, than duc
su sach » so sach, vu sach
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi
thiet » thieu

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 tham nhung ((x hoi) or (o hoi)). hieu van tham duc tan hanh lai ((va triet) OR (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach tham nhung ((x hoi) OR (o hoi)). hieu van tham duc tan hanh lai ((va triet) OR (va thiet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach tham nhung ((x hoi) or (o hoi)). hieu van tham duc tan hanh lai ((va triet) OR (va thiet))*".