Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
chat duc » chat xuc, chat doc, chet duoc
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
va chat » van chat, va phat, cao chat
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
ma hoi » mai hoi, xa hoi, ma hoa
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: ((te sach) or (toc sach)) ty nang ma hoi. hieu va chat duc va hanh di ((cua te) OR (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ty nang ma hoi. hieu va chat duc va hanh di ((cua te) OR (cua tu)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ty nang ma hoi. hieu va chat duc va hanh di ((cua te) OR (cua tu))".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ty nang ma hoi. hieu va chat duc va hanh di ((cua te) OR (cua tu))*.