Perhaps you should try some spelling variations:
cham viet » pham viet, chat viet, chuan viet
cam viet » ca viet, cao viet, nam viet
hanh lai » hanh lam, hanh tai, thanh lap
van hanh » van thanh, ban hanh, van anh
cham duc » pham duc, cham soc, pham duy
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
ty hang » ly hang, ty xang, thi hang
duc van » duc va, duc tan, duc manh
ty nang » ky nang, ty xang, ly nang
tu sach » thu sach, su sach, te sach
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 ((ty nang) OR (ty hang)) x hoi. hieu van cham duc van hanh lai ((cam viet) or (cham viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty nang) OR (ty hang)) x hoi. hieu van cham duc van hanh lai ((cam viet) OR (cham viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty nang) OR (ty hang)) x hoi. hieu van cham duc van hanh lai ((cam viet) or (cham viet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty nang) OR (ty hang)) x hoi. hieu van cham duc van hanh lai ((cam viet) or (cham viet))*.