Perhaps you should try some spelling variations:
doan manh » doan minh, hoang manh, tran manh
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
dan manh » dang manh, van manh, day manh
co viet » so viet, o viet, hoc viet
sach ky » sach y, sach ty, sach kem
sac ky » cac ky, sai ky
vai co » mai co, tai co, voi co
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) OR (sac ky)) nang x hoi. hieu van nam thuc ((dan manh) or (doan manh)) vai co viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) nang x hoi. hieu van nam thuc ((dan manh) OR (doan manh)) vai co viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sac ky)) nang x hoi. hieu van nam thuc ((dan manh) or (doan manh)) vai co viet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sac ky)) nang x hoi. hieu van nam thuc ((dan manh) or (doan manh)) vai co viet*.