Perhaps you should try some spelling variations:
va tuyen » va truyen, tac tuyen, ke tuyen
va trien » va truyen, va thiet, va tieng
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
thi van » thi lan, thi hanh, thi nang
hanh di » hanh vi, hanh de, hang di
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
van am » van nam, van lam, van dam

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang xa) OR (nang ma)) hoi. thi van am thuc dan hanh di ((va trien) OR (va tuyen))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang xa) or (nang ma)) hoi. thi van am thuc dan hanh di ((va trien) OR (va tuyen))~".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang xa) or (nang ma)) hoi. thi van am thuc dan hanh di ((va trien) OR (va tuyen))*.