Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » thien van, lieu va, hieu ve
luoc van » luoc can, luoc va, luc van
toc sach » hoc sach, doc sach, thuoc sach
hieu va » lieu va, hieu qua
sach tu » sach thu, cach tu, sach ty
nang xa » nang x, lang xa, nang ma
tu nang » tru nang, tu nong, tu nano
luan va » luan van
luat va » xuat va, luat ve, suat va

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach tu nang xa hoi. ((hieu van) OR (hieu va)) tom luoc van ((luan va) or (luat va)) cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tu nang xa hoi. ((hieu van) OR (hieu va)) tom luoc van ((luan va) OR (luat va)) cua triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach tu nang xa hoi. ((hieu van) OR (hieu va)) tom luoc van ((luan va) or (luat va)) cua triet*".