Perhaps you should try some spelling variations:
cac thuc » cach thuc, cac thu, cay thuc
kinh tai » hinh tai, dinh tai, kinh hai
can thuc » dan thuc, van thuc, cay thuc
co sach » cuon sach, hoc sach
tai cuu » tai cuc, tai buu, tai cua
va kinh » va tinh, qua kinh
cuu tre » cua tre, cau tren, cau treo
hieu ve » hieu va, hieu van
hang xa » hoang xa, hang va, hang ca
ly hang » ly quang
bo sach » hoc sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((co sach) or (bo sach)) ly hang xa hoi. hieu ve ((cac thuc) OR (can thuc)) va kinh tai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((co sach) OR (bo sach)) ly hang xa hoi. hieu ve ((cac thuc) OR (can thuc)) va kinh tai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((co sach) or (bo sach)) ly hang xa hoi. hieu ve ((cac thuc) OR (can thuc)) va kinh tai cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((co sach) or (bo sach)) ly hang xa hoi. hieu ve ((cac thuc) OR (can thuc)) va kinh tai cuu tre*.