Perhaps you should try some spelling variations:
thanh ve » thanh va, thanh vien, thanh van
hieu van » hieu va, thien van, lieu va
vu sach » vu bach, su sach, vu khach
sach ty » sach y, sach tu, sach thu
hanh ve » hanh vi, hanh va, hanh kem
duc ban » duc tan, duc van, dua ban
cau duc » cao duc, cau luc, chu duc
van cau » van dau, van hau, van chat
hang ca » hang va, nang cao, hang tai
ty hang » ly hang, ty xang, thi hang
ca hoi » cau hoi, cua hoi, xa hoi
cua tu » cua tuc, cua cu, cua te
cua su » qua su

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ty hang ca hoi. hieu van cau duc ban ((thanh ve) or (hanh ve)) ((cua tu) or (cua su))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ty hang ca hoi. hieu van cau duc ban ((thanh ve) OR (hanh ve)) ((cua tu) OR (cua su)).
• Adding a wildcard symbol may retrieve word variants: vu sach ty hang ca hoi. hieu van cau duc ban ((thanh ve) or (hanh ve)) ((cua tu) or (cua su))*.