Perhaps you should try some spelling variations:
quan cau » quang cao, toan cau, quan ha
cau tren » cu tren, dau tren, ca tren
sach ky » sac ky, sach ty, sach kem
lang xa » lang ha, dang xay, lang van
qua cau » qua cac, qua ca, qua cai
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
va cau » van cau, va cac, va dau

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 ky) OR (sach y)) lang xa hoi. hieu ((qua cau) or (quan cau)) truc va hanh va cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach y)) lang xa hoi. hieu ((qua cau) OR (quan cau)) truc va hanh va cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) OR (sach y)) lang xa hoi. hieu ((qua cau) or (quan cau)) truc va hanh va cau tren".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) OR (sach y)) lang xa hoi. hieu ((qua cau) or (quan cau)) truc va hanh va cau tren*.