Perhaps you should try some spelling variations:
thien van » thi van
hanh dai » hanh tai, hanh dao, vanh dai
van hanh » van thanh, ban hanh, van anh
tran van » luan van
cau tran » cau tra, cau tren, chu trang
nang xa » nang x, lang xa, mang xa
van cau » van dau, van hau, van chat
nang ma » tang ma, sang ma, nang cao
sach tu » sach thu, cach tu, sach ty
sac ky » cac ky, sai ky
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: tu ((sach tu) or (sac ky)) ((nang xa) OR (nang ma)) hoi. thien van cau tran van hanh dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach tu) OR (sac ky)) ((nang xa) OR (nang ma)) hoi. thien van cau tran van hanh dai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach tu) or (sac ky)) ((nang xa) OR (nang ma)) hoi. thien van cau tran van hanh dai cua te".
• Adding a wildcard symbol may retrieve word variants: tu ((sach tu) or (sac ky)) ((nang xa) OR (nang ma)) hoi. thien van cau tran van hanh dai cua te*.