Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh vi » hanh vi, thanh va, thanh ve
vu sach » vu bach, su sach, vu khach
cua tuc » cua duc, cua tu, cua thuoc
duc ban » duc tan, duc van, dua ban
cam duc » cam xuc, cao duc, pham duc
qua cam » qua cham, qua cac, qua ca
hang ca » hang va, nang cao, hang tai
ty hang » ly hang, ty xang, thi hang
so sach » so sanh, bo sach, co sach
ca hoi » cau hoi, cua hoi, xa hoi
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) or (so sach)) ty hang ca hoi. hieu qua cam duc ban thanh vi ((cua tuc) or (cua su))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (so sach)) ty hang ca hoi. hieu qua cam duc ban thanh vi ((cua tuc) OR (cua su)).
• Adding a wildcard symbol may retrieve word variants: ((vu sach) or (so sach)) ty hang ca hoi. hieu qua cam duc ban thanh vi ((cua tuc) or (cua su))*.