Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
hieu van » hieu va, thien van, lieu va
ve triet » su triet
sach thu » sach thue, sach thieu, sach tham
va trien » va truyen, va thiet, va tuyen
thu nang » thi nang, thu hang, thu bang
nam duc » nam duoc, pham duc, nam thuc
hang di » hang doi, hang vi, hang dien
hanh de » hanh ve, hanh kem
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat sach thu nang o hoi. hieu van nam duc va ((hanh de) or (hang di)) ((ve triet) OR (va trien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach thu nang o hoi. hieu van nam duc va ((hanh de) OR (hang di)) ((ve triet) OR (va trien))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach thu nang o hoi. hieu van nam duc va ((hanh de) or (hang di)) ((ve triet) OR (va trien))*".