Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
nam thuc » nam thuoc, am thuc, nam thu
cau treo » cau theo, cau tren, cau triet
dau vai » dau hai, dau tai
sach ky » sac ky, sach y, sach ty
cu tren » tu tren, dua tren
thuc va » thuc vat, thuc dan, thuc day
hieu ha » hieu hoa, hieu va, hieu ca
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
dau va » dau ve, lau va

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ky lang xa hoi. hieu ha nam thuc va ((dau vai) or (dau va)) ((cau treo) or (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ky lang xa hoi. hieu ha nam thuc va ((dau vai) OR (dau va)) ((cau treo) OR (cu tren)).
• Adding a wildcard symbol may retrieve word variants: hoc sach ky lang xa hoi. hieu ha nam thuc va ((dau vai) or (dau va)) ((cau treo) or (cu tren))*.