Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, va tinh
bo sach » co sach, hoc sach
sach tu » sach thu, cach tu, sach ty
va hanh » van hanh, va danh, ban hanh
cam duc » cam xuc, cao duc, pham duc
hieu va » lieu va, hieu qua
tu nano » truc nano
hieu ve » hieu van
nano x » nano 1, nano o
vi cua » vai cua, di cua
cua te » cua tu
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: bo sach tu nano x hoi. ((hieu ve) or (hieu va)) cam duc ((va hanh) OR (va thanh)) vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: bo sach tu nano x hoi. ((hieu ve) OR (hieu va)) cam duc ((va hanh) OR (va thanh)) vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "bo sach tu nano x hoi. ((hieu ve) or (hieu va)) cam duc ((va hanh) OR (va thanh)) vi cua te".
• Adding a wildcard symbol may retrieve word variants: bo sach tu nano x hoi. ((hieu ve) or (hieu va)) cam duc ((va hanh) OR (va thanh)) vi cua te*.