Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
duc gia » quoc gia
cam duc » cam xuc, cao duc, pham duc
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
ty lang » tay lang, ty xang, ty hang
vi cau » va cau, ve cau, viet cau
di cau » da cau, diem cau
ve cam » ve cham, ve cac, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ty lang xa hoi. hieu ve cam duc gia thanh ((vi cau) OR (di cau)) treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ty lang xa hoi. hieu ve cam duc gia thanh ((vi cau) OR (di cau)) treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ty lang xa hoi. hieu ve cam duc gia thanh ((vi cau) OR (di cau)) treo".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ty lang xa hoi. hieu ve cam duc gia thanh ((vi cau) OR (di cau)) treo*.