Perhaps you should try some spelling variations:
vat hanh » vat thanh, van hanh, va hanh
tay lang » tai lang, tay tang, tay quang
tu xach » tu hach, tu sach
cau hoc » cau hoi, cau hoa, cao hoc
hoc vat » hoc va, hoc viet, thuc vat
hieu ke » hieu kem, chieu ke, hieu ky
lang ha » long ha
tu cach » tu cac
ke cau » ket cau
di cua » doi cua, de cua, do cua

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: ((tu xach) OR (tu cach)) tay lang ha noi. hieu ke cau hoc vat hanh ((di cua) OR (dai cua)) te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu xach) or (tu cach)) tay lang ha noi. hieu ke cau hoc vat hanh ((di cua) OR (dai cua)) te~".
• Adding a wildcard symbol may retrieve word variants: ((tu xach) or (tu cach)) tay lang ha noi. hieu ke cau hoc vat hanh ((di cua) OR (dai cua)) te*.