Perhaps you should try some spelling variations:
hieu quan » hieu qua, lieu quan, thien quan
quan nam » quang nam, xuan nam, quan am
dang xay » dang van, van xay
nam thuc » nam thuoc, am thuc, nam thu
cuu tre » cau tren, cau treo
dan vai » dan va, dan tai, dan vat
thuc va » thuc vat, thuc dan, thuc day
vu sach » vu bach, su sach, vu khach
sach ty » sach y, sach tu, sach thu
lang xa » lang ha, lang van
cua tre » cua te, cua triet, dua tren
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: vu sach ty ((lang xa) or (dang xay)) hoi. hieu quan nam thuc va dan vai ((cuu tre) OR (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ty ((lang xa) OR (dang xay)) hoi. hieu quan nam thuc va dan vai ((cuu tre) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ty ((lang xa) or (dang xay)) hoi. hieu quan nam thuc va dan vai ((cuu tre) OR (cua tre))".
• Adding a wildcard symbol may retrieve word variants: vu sach ty ((lang xa) or (dang xay)) hoi. hieu quan nam thuc va dan vai ((cuu tre) OR (cua tre))*.