Perhaps you should try some spelling variations:
thuc day » thuc dan, thuc vat
tai lang » tai cong, thi lan, tai san
day hanh » day nhanh, day thanh, dao hanh
hieu van » hieu va, thien van, lieu va
cam thuc » am thuc, nam thuc, cam thu
su sach » so sach
hanh vu » hanh vi, hanh va, hanh tu
vu sach » vu bach, vu khach
van cam » van nam, van lam, van cau
ha hoi » hoa hoi, ha noi, va hoi
vu va » vu van, tu va, su va
thiet* » thieu*

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