Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
nam thuc » nam thuoc, am thuc, nam thu
tu sach » thu sach, su sach, te sach
lo nang » ho nang, ly nang, loai nang
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
vi cua » vai cua, di 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) or (thu hoach)) lo nang xa hoi. ((hieu van) or (hieu va)) nam thuc va hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu hoach)) lo nang xa hoi. ((hieu van) OR (hieu va)) nam thuc va hanh vi cua vat.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu hoach)) lo nang xa hoi. ((hieu van) or (hieu va)) nam thuc va hanh vi cua vat*.