Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
van thang » van thanh, van khang, van than
toc sach » hoc sach, doc sach, thuoc sach
van hang » van khang, van hoang, ban hang
nang mai » nang ma, nang tai, lang mai
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ca viet » va viet, co viet, hoa viet
y nang » ky nang, ly nang, v nang
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y nang mai hoi. hieu ve cham thuc ((van hang) OR (van thang)) dau ((cua te) or (ca viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang mai hoi. hieu ve cham thuc ((van hang) OR (van thang)) dau ((cua te) OR (ca viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y nang mai hoi. hieu ve cham thuc ((van hang) OR (van thang)) dau ((cua te) or (ca viet))".
• Adding a wildcard symbol may retrieve word variants: toc sach y nang mai hoi. hieu ve cham thuc ((van hang) OR (van thang)) dau ((cua te) or (ca viet))*.