Perhaps you should try some spelling variations:
thien van » thi van
hieu van » hieu va, lieu va, hieu ve
sach van » sach han, sach va, bach van
van hanh » van thanh, ban hanh, van anh
dau luan » dan luan, dat luan, khau luan
hanh le » thanh le, hanh ve, hanh de
te sach » toc sach
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
cua tre » cua te, cuu tre, cua triet
le cua » ly cua

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 van ((nang xa) OR (nang ma)) hoi. ((hieu van) or (thien van)) dau luan van hanh le cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach van ((nang xa) OR (nang ma)) hoi. ((hieu van) OR (thien van)) dau luan van hanh le cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach van ((nang xa) OR (nang ma)) hoi. ((hieu van) or (thien van)) dau luan van hanh le cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach van ((nang xa) OR (nang ma)) hoi. ((hieu van) or (thien van)) dau luan van hanh le cua tre*.