Perhaps you should try some spelling variations:
day thanh » dao thanh, dat thanh, da thanh
va thieu » va thiet, va hieu, va tieu
va triet » va thiet, va trien, ve triet
thanh va » thanh van, hanh va, thanh ha
thuc day » thuc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
sach ly » sach y, sach lo, sach hay
nang ma » tang ma, sang ma, nang cao
sach ty » sach y, sach tu, sach thu
ma hoi » mai hoi, xa hoi, ma hoa

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 ly) OR (sach ty)) nang ma hoi. hieu van nam thuc day thanh va ((va triet) or (va thieu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ly) OR (sach ty)) nang ma hoi. hieu van nam thuc day thanh va ((va triet) OR (va thieu)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ly) OR (sach ty)) nang ma hoi. hieu van nam thuc day thanh va ((va triet) or (va thieu))".
• Adding a wildcard symbol may retrieve word variants: su ((sach ly) OR (sach ty)) nang ma hoi. hieu van nam thuc day thanh va ((va triet) or (va thieu))*.