Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
dang xay » dang van, van xay
nam thuc » nam thuoc, am thuc, nam thu
cau tren » cu tren, dau tren, ca tren
lang xa » lang ha, lang van
sach ty » sach y, sach tu, sach thu
thuc va » thuc vat, thuc dan, thuc day
dan vai » dan va, dan tai, dan vat
cuu tre » cua tre, cau treo
su sach » so sach, vu sach
va dan » ca dan, va dao, va dau

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 quang nam thuc va dan vai ((cuu tre) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((lang xa) OR (dang xay)) hoi. hieu quang nam thuc va dan vai ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((lang xa) or (dang xay)) hoi. hieu quang nam thuc va dan vai ((cuu tre) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((lang xa) or (dang xay)) hoi. hieu quang nam thuc va dan vai ((cuu tre) OR (cau tren))*.