Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, can thuc
tay lang » tai lang, tay tang, tay quang
hieu van » hieu va, thien van, lieu va
su sach » so sach
vu sach » vu bach, vu khach
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
vi cua » vai cua, di cua
cua tu » cua tuc, cua su, cua cu

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)) tay lang xa hoi. ((hieu ve) or (hieu van)) cau thuc va hanh vi cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) tay lang xa hoi. ((hieu ve) OR (hieu van)) cau thuc va hanh vi cua tu.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) tay lang xa hoi. ((hieu ve) or (hieu van)) cau thuc va hanh vi cua tu*.