Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
tang ma » mang may, tang van
thuc va » thuc vat, thuc dan, thuc day
su sach » so sach, vu sach
va dan » ca dan, va dao, va dau
vi ve » va ve, gi ve, vi he
ve ve » de ve, va ve, ke ve

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((tang ma) OR (nang cao)) hoi. hieu van nam thuc va dan ((vi ve) OR (ve ve)) triet~.
• Adding a wildcard symbol may retrieve word variants: su sach y ((tang ma) or (nang cao)) hoi. hieu van nam thuc va dan ((vi ve) or (ve ve)) triet*.