Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
su sach » vu sach
tri cuu » tri cua, tra cuu, trinh cuu
va dinh » van dinh, va kinh, va tinh
va danh » va dan, va hanh, dia danh
cuu tre » cua tre, cau tren, cau treo
hieu ve » hieu va, hieu van
mang xa » lang xa, mang may, dang xay
ty mang » ty xang, ty hang, tin mang
so sach » so sanh, bo sach, co sach
ve cam » ve cham, ve cac, va cam

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) OR (so sach)) ty mang xa hoi. hieu ve cam thuc ((va danh) or (va dinh)) tri cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) ty mang xa hoi. hieu ve cam thuc ((va danh) OR (va dinh)) tri cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) OR (so sach)) ty mang xa hoi. hieu ve cam thuc ((va danh) or (va dinh)) tri cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) OR (so sach)) ty mang xa hoi. hieu ve cam thuc ((va danh) or (va dinh)) tri cuu tre*.