Perhaps you should try some spelling variations:
manh thanh » danh thanh, minh thanh, manh thang
van cham » van chat, van tham, va cham
hoai vai » hoai cai, thoai van, hoi va
duc manh » suc manh, duc anh, duc minh
cham duc » pham duc, cham soc, pham duy
hieu van » hieu va, thien van, lieu va
hoai va » hoi va, loai va, hoa va
ty nang » ty xang, ty hang, ly nang
su sach » so sach, vu sach
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((ty nang) OR (ky nang)) o hoi. hieu van cham duc manh thanh ((hoai va) or (hoai vai)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ty nang) OR (ky nang)) o hoi. hieu van cham duc manh thanh ((hoai va) OR (hoai vai)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ty nang) OR (ky nang)) o hoi. hieu van cham duc manh thanh ((hoai va) or (hoai vai)) viet".
• Adding a wildcard symbol may retrieve word variants: su sach ((ty nang) OR (ky nang)) o hoi. hieu van cham duc manh thanh ((hoai va) or (hoai vai)) viet*.