Perhaps you should try some spelling variations:
dang xay » dang van, van xay
nam thuc » nam thuoc, am thuc, nam thu
su sach » so sach, vu sach
thuc va » thuc vat, thuc dan, thuc day
sach ty » sach y, sach tu, sach thu
qua nam » quan nam, cua nam, quang nam
lang xa » lang ha, lang van
dan vi » doan vi, don vi, gan vi
dan va » doan va, dan ca, ban 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: su sach ty ((lang xa) or (dang xay)) hoi. hieu qua nam thuc va ((dan vi) OR (dan va)) cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((lang xa) OR (dang xay)) hoi. hieu qua nam thuc va ((dan vi) OR (dan va)) cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((lang xa) or (dang xay)) hoi. hieu qua nam thuc va ((dan vi) OR (dan va)) cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((lang xa) or (dang xay)) hoi. hieu qua nam thuc va ((dan vi) OR (dan va)) cua te*.