Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
dao nang » cao nang, dai nang, dao nung
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
da nang » cam nang, kha nang, cao nang
thuc va » thuc vat, thuc dan, thuc day
mai hoi » mai khoi, dai hoi, lai hoi
di cua » dai cua, doi cua, de cua

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 ((dao nang) OR (da nang)) ((xa hoi) or (mai hoi)). hieu van nam thuc va hanh di cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((dao nang) OR (da nang)) ((xa hoi) OR (mai hoi)). hieu van nam thuc va hanh di cua vat*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((dao nang) OR (da nang)) ((xa hoi) or (mai hoi)). hieu van nam thuc va hanh di cua vat*".