Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
cam thuc » am thuc, nam thuc, cam thu
hoi dang » hoi dan, hoi lang, hai dang
hoi dong » hop dong, hoat dong, ha dong
hieu van » hieu va, thien van, lieu va
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
su sach » so sach, vu 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 ((hoi dang) or (hoi dong)) xa hoi. hieu van cam thuc ((va hanh) OR (va danh)) vi va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((hoi dang) OR (hoi dong)) xa hoi. hieu van cam thuc ((va hanh) OR (va danh)) vi va triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((hoi dang) or (hoi dong)) xa hoi. hieu van cam thuc ((va hanh) OR (va danh)) vi va triet*".