Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
nam thuc » nam thuoc, am thuc, nam thu
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
hieu ve » hieu van
thuc va » thuc vat, thuc dan, thuc day
vi cua » vai cua, di cua
cua te » cua tu
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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 (thuat sach)) ky nang o hoi. ((hieu ve) or (hieu va)) nam thuc va hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuat sach)) ky nang o hoi. ((hieu ve) OR (hieu va)) nam thuc va hanh vi cua te.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuat sach)) ky nang o hoi. ((hieu ve) or (hieu va)) nam thuc va hanh vi cua te*.