Perhaps you should try some spelling variations:
doan manh » doan minh, hoang manh, tran manh
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
dan manh » dang manh, van manh, day manh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
so viet » hoc viet
vai so » dai so, tai so, va so
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: tu sach ky nang x hoi. hieu van nam thuc ((dan manh) OR (doan manh)) vai so viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. hieu van nam thuc ((dan manh) OR (doan manh)) vai so viet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. hieu van nam thuc ((dan manh) OR (doan manh)) vai so viet*.