Perhaps you should try some spelling variations:
thuat san » thuat toan, thuat song, thuat lanh
cham thuc » nham thuc, pham thuc, tham thuc
hang hai » hoang hai, hang tai, thanh hai
hang lai » hang tai, hang loi, hang la
thuc va » thuc vat, thuc dan, thuc day
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
so sach » so sanh, bo sach, co sach
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: ((thuat san) or (so sach)) ky tang xa hoi. hieu ve cham thuc va ((hang lai) OR (hang hai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuat san) OR (so sach)) ky tang xa hoi. hieu ve cham thuc va ((hang lai) OR (hang hai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuat san) or (so sach)) ky tang xa hoi. hieu ve cham thuc va ((hang lai) OR (hang hai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thuat san) or (so sach)) ky tang xa hoi. hieu ve cham thuc va ((hang lai) OR (hang hai)) cua tre*.