Perhaps you should try some spelling variations:
khac thuc » khac phuc, thach thuc, khau thuoc
qua khac » qua khai, qua khao, cua khach
tu sach » thu sach, su sach, te sach
van hoc » van hoa
thuc va » thuc vat, thuc dan, thuc day
va dinh » van dinh, va kinh, va tinh
dinh vi » dinh ve, dinh viet, dinh tri
y lang » o lang, tay lang, yen lang
_ lang » o lang, _ land
cua tu » cua tuc, cua su, cua cu

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) OR (_ lang)) van hoc. hieu qua khac thuc va dinh vi ((cua te) or (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y lang) OR (_ lang)) van hoc. hieu qua khac thuc va dinh vi ((cua te) OR (cua tu)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y lang) OR (_ lang)) van hoc. hieu qua khac thuc va dinh vi ((cua te) or (cua tu))".
• Adding a wildcard symbol may retrieve word variants: tu sach ((y lang) OR (_ lang)) van hoc. hieu qua khac thuc va dinh vi ((cua te) or (cua tu))*.