Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
danh dau » lanh dao, hang dau, danh tu
dinh dau » dinh dat, dinh du, dinh dao
tham xuc » tham nuoc, tham thuc, pham duc
cua viet » ca viet, hoa viet, cua vat
tang ma » mang may, tang van
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
xuc nam » duc nam, xuc cam, cuc nam
nang ma » sang ma, nang cao, mang may
va tham » van tham, va cham, va thanh

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 ky ((nang ma) or (tang ma)) hoa. hieu va tham xuc nam ((dinh dau) OR (danh dau)) cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((nang ma) OR (tang ma)) hoa. hieu va tham xuc nam ((dinh dau) OR (danh dau)) cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky ((nang ma) or (tang ma)) hoa. hieu va tham xuc nam ((dinh dau) OR (danh dau)) cua viet".
• Adding a wildcard symbol may retrieve word variants: toc sach ky ((nang ma) or (tang ma)) hoa. hieu va tham xuc nam ((dinh dau) OR (danh dau)) cua viet*.