Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
thu nang » thi nang, thu hang, tho nang
thu bang » thu ban, thu hang, chu bang
chat soc » cham soc, chat hoc, chat doc
dinh vi » dinh ve, dinh viet, dinh tri
va dinh » van dinh, va kinh, va tinh
te sach » toc sach
hieu va » lieu va, hieu qua
cao hoi » cau hoi, co hoi, cao hoc
soc va » hoc va, loc va, doc va
vi cua » vai cua, di cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ((thu nang) or (thu bang)) cao hoi. ((hieu van) OR (hieu va)) chat soc va dinh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((thu nang) OR (thu bang)) cao hoi. ((hieu van) OR (hieu va)) chat soc va dinh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((thu nang) or (thu bang)) cao hoi. ((hieu van) OR (hieu va)) chat soc va dinh vi cua te".
• Adding a wildcard symbol may retrieve word variants: te sach ((thu nang) or (thu bang)) cao hoi. ((hieu van) OR (hieu va)) chat soc va dinh vi cua te*.