Perhaps you should try some spelling variations:
hoc viet » hoc hien
cam thuc » am thuc, nam thuc, can thuc
va hanh » van hanh, va thanh, va danh
cam thu » nam thu, cac thu, ca thu
sanh ky » hanh ky, sang ky, nganh ky
so sanh » do sanh
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
hieu ve » hieu va, hieu van
vi hoc » li hoc, va hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sanh ky ((nang ma) or (tang ma)) hoi. hieu ve ((cam thuc) or (cam thu)) va hanh vi hoc viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sanh ky ((nang ma) OR (tang ma)) hoi. hieu ve ((cam thuc) OR (cam thu)) va hanh vi hoc viet.
• Adding a wildcard symbol may retrieve word variants: so sanh ky ((nang ma) or (tang ma)) hoi. hieu ve ((cam thuc) or (cam thu)) va hanh vi hoc viet*.