Perhaps you should try some spelling variations:
cua quoc » cua nuoc, cua thuoc
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
nam thuc » nam thuoc, am thuc, nam thu
hieu va » lieu va, hieu qua
hieu ve » hieu van
vu sach » vu bach, su sach, vu khach
y nang » ky nang, ly nang, may nang
v nang » va nang, vu nang, van nang
vi cua » vai cua, di cua
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: vu sach ((y nang) or (v nang)) o hoi. ((hieu ve) or (hieu va)) nam thuc van hanh vi cua quoc~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ((y nang) OR (v nang)) o hoi. ((hieu ve) OR (hieu va)) nam thuc van hanh vi cua quoc.
• Adding a wildcard symbol may retrieve word variants: vu sach ((y nang) or (v nang)) o hoi. ((hieu ve) or (hieu va)) nam thuc van hanh vi cua quoc*.