Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
cam thuc » am thuc, nam thuc, cam thu
va thanh » gia thanh, ban thanh, va tinh
hoi lang » hoa lang, hoi dan
hieu van » hieu va, thien van, lieu va
va hanh » van hanh, va danh, ban hanh
su sach » vu sach
lang xa » lang ha, dang xay, lang van
so sach » so sanh, bo sach, co sach
van cam » van nam, van lam, van cau
vi va » vi van, vai va, vu va

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)) hoi lang xa hoi. hieu van cam thuc ((va hanh) OR (va thanh)) vi va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) hoi lang xa hoi. hieu van cam thuc ((va hanh) OR (va thanh)) vi va triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) hoi lang xa hoi. hieu van cam thuc ((va hanh) OR (va thanh)) vi va triet*".