Perhaps you should try some spelling variations:
cham viet » pham viet, chat viet, chuan viet
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
cham duc » pham duc, cham soc, pham duy
van hanh » van thanh, ban hanh, van anh
hanh tai » thanh tai, hang tai, han tai
cam viet » ca viet, cao viet, nam viet
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
duc van » duc va, duc tan, duc manh
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 x hoi. hieu van cham duc van hanh tai ((cam viet) or (cham viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang x hoi. hieu van cham duc van hanh tai ((cam viet) OR (cham viet)).
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang x hoi. hieu van cham duc van hanh tai ((cam viet) or (cham viet))*.