Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
cua viet » ca viet, hoa viet, cua dieu
sach ly » sach y, sach lo, sach hay
sach ty » sach y, sach tu, sach thu
cao hoi » cau hoi, co hoi, cao hoc
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ly) or (sach ty)) nang cao hoi. hieu van nam thuc va hanh vi ((cua viet) or (cua vat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ly) OR (sach ty)) nang cao hoi. hieu van nam thuc va hanh vi ((cua viet) OR (cua vat)).
• Adding a wildcard symbol may retrieve word variants: tu ((sach ly) or (sach ty)) nang cao hoi. hieu van nam thuc va hanh vi ((cua viet) or (cua vat))*.