Perhaps you should try some spelling variations:
sach tay » xach tay, sach hay, sach nay
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
va hanh » van hanh, va thanh, va danh
cau hoc » cau hoi, cau hoa, cao hoc
hieu ve » hieu va
long ha » dong ha, cong ha, dong hoa
lang xa » lang ha, dang xay, lang van
vi cua » vai cua, di cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach tay ((lang xa) or (long ha)) hoi. ((hieu ve) OR (hieu van)) cau hoc va hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tay ((lang xa) OR (long ha)) hoi. ((hieu ve) OR (hieu van)) cau hoc va hanh vi cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tay ((lang xa) or (long ha)) hoi. ((hieu ve) OR (hieu van)) cau hoc va hanh vi cua te*".