Perhaps you should try some spelling variations:
cach thuc » anh thuc, cac thu
sach tu » sach thu, cach tu, sach ty
cac tho » cac thoi, cac tro, cac thu
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
tho va » tho van, tao va, tho ca
dan vi » doan vi, don vi, dan va
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach tu) or (cach thuc)) lang xa hoi. hieu ve cac tho va ((dan vi) or (hoang thi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach tu) OR (cach thuc)) lang xa hoi. hieu ve cac tho va ((dan vi) OR (hoang thi)) cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach tu) or (cach thuc)) lang xa hoi. hieu ve cac tho va ((dan vi) or (hoang thi)) cua tre*.