Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
cam truc » cau truc, nam truc, lam truoc
truc van » truc va, thuc van, truc ban
van hanh » van thanh, ban hanh, van anh
su triet » su viet, su tien, ve triet
te sach » toc sach
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
hanh va » hang va, hanh vi

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 y ((nang xa) OR (lang xa)) hoi. ((hieu van) or (hieu va)) cam truc van hanh va su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y ((nang xa) OR (lang xa)) hoi. ((hieu van) OR (hieu va)) cam truc van hanh va su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y ((nang xa) OR (lang xa)) hoi. ((hieu van) or (hieu va)) cam truc van hanh va su triet".
• Adding a wildcard symbol may retrieve word variants: te sach y ((nang xa) OR (lang xa)) hoi. ((hieu van) or (hieu va)) cam truc van hanh va su triet*.