Perhaps you should try some spelling variations:
xang cao » lang cao, quang cao, hoang cao
tu sach » thu sach, su sach, te sach
cac duc » cac du, cao duc, cac dac
sach tu » sach thu, cach tu, sach ty
hieu ve » hieu va, hieu van
cua tuc » cua duc, cua tu, cua thuoc
ve cac » va cac, vien cac
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
cua te » cua tu

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 ((xang cao) OR (nang cao)) hoa. hieu ve cac duc va dan vi ((cua te) or (cua tuc))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tu ((xang cao) OR (nang cao)) hoa. hieu ve cac duc va dan vi ((cua te) OR (cua tuc))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tu ((xang cao) OR (nang cao)) hoa. hieu ve cac duc va dan vi ((cua te) or (cua tuc))*".