Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, nam thu, nam tu
sach tay » xach tay, sach hay, sach nay
cau tren » cu tren, dau tren, ca tren
tay tang » tay lang, tay trung, tay quang
hieu va » lieu va, hieu qua
tang ma » mang may, tang van
va hanh » van hanh, va thanh, va danh
cam tuc » cam xuc, cam tu, dam thuc
ma hoi » mai hoi, xa hoi, ma hoa
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: toc sach tay tang ma hoi. hieu va ((cam tuc) or (((nam thuc) OR (am thuc)))) va hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tay tang ma hoi. hieu va ((cam tuc) OR (((nam thuc) OR (am thuc)))) va hanh vi cau tren*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach tay tang ma hoi. hieu va ((cam tuc) or (((nam thuc) OR (am thuc)))) va hanh vi cau tren*".