Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thu sach » tu sach, thuat sach, thu hoach
cua viet » ca viet, hoa viet, cua vat
nang xa » lang xa, nang ma, mang xa
qua cac » cua cac
cac duc » cac du, cao duc, cac dac
duc ca » duc cac, duc va, duc ha
ca dan » cac dan, ca dao
dan va » doan va, dan ca, ban va
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (thuoc sach)) y ((nang xa) or (nang x)) hoi. hieu qua cac duc ca dan va cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuoc sach)) y ((nang xa) OR (nang x)) hoi. hieu qua cac duc ca dan va cua viet.
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (thuoc sach)) y ((nang xa) or (nang x)) hoi. hieu qua cac duc ca dan va cua viet*.