Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
cau treo » cau theo, cau tren, cau triet
lang xa » dang xay, lang van
lang ha » long ha
sach ty » sach y, sach tu, sach thu
vu hanh » vu khanh, vu thanh, vu anh
du hanh » dieu hanh, duy khanh, luu hanh
hieu ke » hieu kem, chieu ke, hieu ky
ke cau » ket cau
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: hoc sach ty ((lang xa) OR (lang ha)) hoi. hieu ke cau truc ((vu hanh) or (du hanh)) vi cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ty ((lang xa) OR (lang ha)) hoi. hieu ke cau truc ((vu hanh) OR (du hanh)) vi cau treo*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ty ((lang xa) OR (lang ha)) hoi. hieu ke cau truc ((vu hanh) or (du hanh)) vi cau treo*".