Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
hieu va » hieu qua
cac tac » cac toc, cac bac, cac dac
van vat » van chat, nhan vat
vat cua » mat cua, bat cua, dat cua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa
tac va » tac da, tac xa, tuc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y nang ma hoi. ((hieu va) or (lieu va)) cac tac va van vat cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ma hoi. ((hieu va) OR (lieu va)) cac tac va van vat cua tre*.