Perhaps you should try some spelling variations:
cau theo » cau thi, cau tao
trinh vi » trinh va, trinh ve, trinh viet
va trinh » van trinh, va tinh, lap trinh
lang ha » long ha
sach ty » sach y, sach tu, sach thu
lang xa » dang xay, lang van
su sach » so sach, vu sach
loc va » hoc va, luc va
vi cau » va cau, ve cau, di cau

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

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