Perhaps you should try some spelling variations:
thanh hai » thanh phan, thanh hoa, thanh san
cam thuc » am thuc, nam thuc, can thuc
nang mai » nang ma, nang tai, nang cai
lang mai » lang dai, lang hai, lang man
bo sach » co sach, hoc sach
cam thu » nam thu, cac thu, ca thu
hieu ve » hieu va, hieu van
sach vu » sach va, sach tu, sach uu
ca viet » va viet, co viet, hoa viet
hai ca » hai cua, hai ba, bai ca

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

• Performing a fuzzy search may retrieve terms with similar spellings: bo sach vu ((nang mai) or (lang mai)) khoi. hieu ve ((cam thuc) OR (cam thu)) gia thanh hai ca viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: bo sach vu ((nang mai) OR (lang mai)) khoi. hieu ve ((cam thuc) OR (cam thu)) gia thanh hai ca viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "bo sach vu ((nang mai) or (lang mai)) khoi. hieu ve ((cam thuc) OR (cam thu)) gia thanh hai ca viet".
• Adding a wildcard symbol may retrieve word variants: bo sach vu ((nang mai) or (lang mai)) khoi. hieu ve ((cam thuc) OR (cam thu)) gia thanh hai ca viet*.