Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang xa » nang x, lang xa, nang ma
qua cac » cua cac
cac tuc » cac toc, cac tu, cac tac
va hanh » van hanh, va thanh, va danh
tuc va » thuc va, truc va, tuc xa
vi cua » vai cua
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y ((nang xa) or (nang cao)) hoi. hieu qua cac tuc va hanh ((vi cua) OR (di cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y ((nang xa) OR (nang cao)) hoi. hieu qua cac tuc va hanh ((vi cua) OR (di cua)) te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y ((nang xa) or (nang cao)) hoi. hieu qua cac tuc va hanh ((vi cua) OR (di cua)) te*".