Perhaps you should try some spelling variations:
hieu san » hieu van, hieu sau, chieu sang
so sach » so sanh, bo sach, co sach
sach tu » sach thu, cach tu, sach ty
tu nang » tru nang, tu nong, tu nano
han tai » hang tai, nhan tai, van tai
va han » va phan, van han, va hanh
cua tu » cua tuc, cua su, cua cu
x hoi » o hoi, x ho, 5 hoi
pham » phan

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach tu nang ((x hoi) or (xa hoi)). hieu san pham duc va han tai ((cua te) or (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach tu nang ((x hoi) OR (xa hoi)). hieu san pham duc va han tai ((cua te) OR (cua tu)).
• Adding a wildcard symbol may retrieve word variants: so sach tu nang ((x hoi) or (xa hoi)). hieu san pham duc va han tai ((cua te) or (cua tu))*.