Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
va triet » va thiet, va trien, ve triet
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
ma hoi » mai hoi, xa hoi, ma hoa
va nam » van nam, ha nam, va nay
cua tu » cua tuc, cua su, cua cu

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 hoi. hieu va nam thuc va hanh vi ((((cua te) or (cua tu))) or (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang ma hoi. hieu va nam thuc va hanh vi ((((cua te) OR (cua tu))) OR (va triet)).
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang ma hoi. hieu va nam thuc va hanh vi ((((cua te) or (cua tu))) or (va triet))*.