Perhaps you should try some spelling variations:
khac thuc » khac phuc, thach thuc, khau thuoc
qua khac » qua khai, qua khao, cua khach
thu sach » thuat sach, thuoc sach, thu hoach
lang van » dang van, tang van, hoang van
dinh vi » dinh ve, dinh viet, dinh tri
va dinh » van dinh, va kinh, va tinh
thuc va » thuc vat, thuc dan, thuc day
tu sach » su sach, te sach, tu cach
van hoc » van hoa
y lang » o lang, _ lang, tay lang
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) OR (thu sach)) y 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) OR (thu sach)) y 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) OR (thu sach)) y 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) OR (thu sach)) y lang van hoc. hieu qua khac thuc va dinh vi ((cua te) or (cua tu))*.