Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
nang nam » dang nam, hang nam, nang lam
thi nang » thi cong, ki nang, thi hanh
hanh di » hanh vi, hanh de, hang di
tu sach » thu sach, te sach, tu cach
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
su sach » so sach, vu sach
di va » dai va, di vao, doi va

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) OR (su sach)) y ((nang xa) OR (nang ma)) hoi. thi nang nam thuc dan hanh di va trien~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) y ((nang xa) OR (nang ma)) hoi. thi nang nam thuc dan hanh di va trien~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) y ((nang xa) OR (nang ma)) hoi. thi nang nam thuc dan hanh di va trien*.