Perhaps you should try some spelling variations:
cua triet » su triet, va triet
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
hang hai » hoang hai, hang tai, thanh hai
cua viet » ca viet, hoa viet, cua vat
nang ma » tang ma, sang ma, nang cao
va pham » van pham, va phat, va phap
va hang » van hang, va nang, va lang
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa

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) or (doc sach)) y nang ma hoi. lieu va pham duc va hang hai ((cua triet) OR (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) y nang ma hoi. lieu va pham duc va hang hai ((cua triet) OR (cua viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) y nang ma hoi. lieu va pham duc va hang hai ((cua triet) OR (cua viet))".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) y nang ma hoi. lieu va pham duc va hang hai ((cua triet) OR (cua viet))*.