Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
lang van » dang van, tang van, hoang van
dang xay » dang van, van xay
nam thuc » nam thuoc, am thuc, nam thu
cua tre » cuu tre, cua triet, dua tren
thuc va » thuc vat, thuc dan, thuc day
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
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: su sach ty ((lang van) or (dang xay)) hoi. hieu quang nam thuc va dan vi ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((lang van) OR (dang xay)) hoi. hieu quang nam thuc va dan vi ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: su sach ty ((lang van) or (dang xay)) hoi. hieu quang nam thuc va dan vi ((cua tre) or (cua te))*.