Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
nang xa » lang xa, nang ma, mang xa
qua cam » qua cham, qua cac, qua ca
luu tre » luu tru, cuu tre, luy tre
cam tu » cam thu, nam tu, dam tu
va dan » ca dan, va dao, va dap
va dau » va dao
vi luu » vi lua

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach y ((nang xa) OR (nang x)) hoi. hieu qua cam tu ((va dan) or (va dau)) vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach y ((nang xa) OR (nang x)) hoi. hieu qua cam tu ((va dan) OR (va dau)) vi luu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach y ((nang xa) OR (nang x)) hoi. hieu qua cam tu ((va dan) or (va dau)) vi luu tre".
• Adding a wildcard symbol may retrieve word variants: hoc sach y ((nang xa) OR (nang x)) hoi. hieu qua cam tu ((va dan) or (va dau)) vi luu tre*.