Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
van hanh » van thanh, ban hanh, van anh
cau luan » cu luan, dau luan, lau luan
hanh ve » hanh vi, hanh va, hanh kem
hieu va » lieu va, hieu qua
hieu ve » hieu van
te sach » toc sach
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
ve su » va su

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 (nang ma)) hoi. ((hieu ve) OR (hieu va)) cau luan van hanh ve su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y ((nang xa) OR (nang ma)) hoi. ((hieu ve) OR (hieu va)) cau luan van hanh ve su triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y ((nang xa) or (nang ma)) hoi. ((hieu ve) OR (hieu va)) cau luan van hanh ve su triet*".