Perhaps you should try some spelling variations:
thuc day » thuc dan, thuc vat
hieu van » hieu va, thien van, lieu va
lam thuc » lam thuoc, am thuc, nam thuc
cau tren » cu tren, dau tren, ca tren
lang xa » lang ha, dang xay, lang van
van lam » van nam
sach ty » sach tu, sach thu, xach tay
day dan » day danh, dao dan, cay dan
dan vai » dan va, dan tai, dan vat
cuu tre » cua tre, cau treo

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc ((sach ty) or (sach y)) lang xa hoi. hieu van lam thuc day dan vai ((cuu tre) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sach ty) OR (sach y)) lang xa hoi. hieu van lam thuc day dan vai ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((sach ty) or (sach y)) lang xa hoi. hieu van lam thuc day dan vai ((cuu tre) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: toc ((sach ty) or (sach y)) lang xa hoi. hieu van lam thuc day dan vai ((cuu tre) OR (cau tren))*.