Perhaps you should try some spelling variations:
hieu sau » hieu su, hieu suat, tieu su
sau cham » cau cham, sau chan, va cham
cham xuc » cam xuc, chat xuc, cham soc
so sach » so sanh, bo sach, co sach
nang xa » lang xa, nang ma, mang xa
van han » van hanh, van phan, van nhan
va han » va phan, va hanh, va hang
thiet » thieu

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 y ((nang xa) or (nang x)) hoi. hieu sau cham xuc ((va han) OR (van han)) mai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y ((nang xa) OR (nang x)) hoi. hieu sau cham xuc ((va han) OR (van han)) mai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y ((nang xa) or (nang x)) hoi. hieu sau cham xuc ((va han) OR (van han)) mai va thiet".
• Adding a wildcard symbol may retrieve word variants: so sach y ((nang xa) or (nang x)) hoi. hieu sau cham xuc ((va han) OR (van han)) mai va thiet*.