Perhaps you should try some spelling variations:
doc sach » hoc sach, nuoc sach, dac sac
toc sach » hoc sach, thuoc sach, nuoc sach
cua viet » ca viet, hoa viet, cua vat
hieu va » lieu va, hieu qua
va pham » van pham, va phat, va phap
va hanh » van hanh, va thanh, va danh
y nang » ky nang, ly nang, v nang
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doc sach) OR (toc sach)) y nang x ho. hieu va pham duc va hanh vi ((cua te) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc sach) OR (toc sach)) y nang x ho. hieu va pham duc va hanh vi ((cua te) OR (cua viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc sach) OR (toc sach)) y nang x ho. hieu va pham duc va hanh vi ((cua te) or (cua viet))".
• Adding a wildcard symbol may retrieve word variants: ((doc sach) OR (toc sach)) y nang x ho. hieu va pham duc va hanh vi ((cua te) or (cua viet))*.