Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
cau tren » cu tren, dau tren, ca tren
thanh vi » hanh vi, thanh va, thanh ve
long ha » dong ha, cong ha, dong hoa
sach ty » sach y, sach tu, sach thu
van cam » van lam, van cau, van dam
hoc ban » hoc bang, hoc dan, hoc bai
su sach » so sach, vu sach
vi cau » va cau, ve cau, di cau

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 ty ((lang ha) OR (long ha)) hoi. hieu ((van cam) or (van nam)) hoc ban thanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((lang ha) OR (long ha)) hoi. hieu ((van cam) OR (van nam)) hoc ban thanh vi cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((lang ha) OR (long ha)) hoi. hieu ((van cam) or (van nam)) hoc ban thanh vi cau tren".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((lang ha) OR (long ha)) hoi. hieu ((van cam) or (van nam)) hoc ban thanh vi cau tren*.