Perhaps you should try some spelling variations:
kham duc » pham duc, kham cuoc, pham duy
van hanh » van thanh, ban hanh, van ban
su sach » so sach, vu sach
lam cua » nam cua, lam chat
van anh » van thanh, tuan anh, van minh
vu kham » vu khanh
sach ty » sach y, sach tu, sach thu
hieu vu » hieu va, hieu ve, hieu su
mai hoi » mai khoi, dai hoi, lai hoi
may hoi » may thoi, tay hoi, may hmi
ty mang » ty xang, ty hang, tin mang
cua tre » cua te, cuu tre, cua triet

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 mang ((may hoi) OR (mai hoi)). hieu vu kham duc ((van hanh) or (van anh)) lam cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty mang ((may hoi) OR (mai hoi)). hieu vu kham duc ((van hanh) OR (van anh)) lam cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty mang ((may hoi) OR (mai hoi)). hieu vu kham duc ((van hanh) or (van anh)) lam cua tre*".