Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
va triet » va thiet, va trien, ve triet
vu sach » vu bach, su sach, vu khach
hieu va » lieu va, hieu qua
cac tac » cac toc, cac bac, cac dac
dan vat » dang vat, van vat, dan dat
dan va » doan va, dan ca, ban va
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (vu sach)) ky nang x hoi. hieu va cac tac da ((dan vat) or (dan va)) va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (vu sach)) ky nang x hoi. hieu va cac tac da ((dan vat) OR (dan va)) va triet.
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (vu sach)) ky nang x hoi. hieu va cac tac da ((dan vat) or (dan va)) va triet*.