Perhaps you should try some spelling variations:
cong tac » cong ty
ban hanh » ban hang
chua tre » chua tri, cua tre, chua trieu
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ky cong » ke cong, ly cong, khu cong
tac hoi » tao hoi, tay hoi, tac hai
van cam » van lam, van cau, van dam
duc ban » duc tan, duc van, dua ban
hanh va » hang va, hanh vi
va chua » vua chua, ca chua, va chu

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 cong tac hoi. hieu ((van cam) or (van nam)) duc ban hanh va chua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky cong tac hoi. hieu ((van cam) OR (van nam)) duc ban hanh va chua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky cong tac hoi. hieu ((van cam) or (van nam)) duc ban hanh va chua tre*.