Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
lang xa » dang xay, lang van
lang ha » long ha
qua cam » qua cham, qua cac, qua ca
cam duc » cam xuc, cao duc, pham duc
va dung » van dung, va duong, vat dung
cuc te » cua te, cuc tieu
thue » thu, thuc, thuy

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 y ((lang xa) or (lang ha)) hoi. hieu qua cam duc va dung tai ((cuc te) OR (cuc thue))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((lang xa) OR (lang ha)) hoi. hieu qua cam duc va dung tai ((cuc te) OR (cuc thue)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((lang xa) or (lang ha)) hoi. hieu qua cam duc va dung tai ((cuc te) OR (cuc thue))".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((lang xa) or (lang ha)) hoi. hieu qua cam duc va dung tai ((cuc te) OR (cuc thue))*.