Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
cac toi » cac thoi
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
hieu va » hieu qua
ma hoi » mai hoi, xa hoi, ma hoa
va dan » ca dan, va dao, va dau
dan va » doan va, dan ca, ban va
va cua » va chua, via cua, ca cua
cac tu » cac thu, cach tu, cac du

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 ky nang ma hoi. ((hieu va) or (lieu va)) ((cac tu) or (cac toi)) va dan va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ma hoi. ((hieu va) OR (lieu va)) ((cac tu) OR (cac toi)) va dan va cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ma hoi. ((hieu va) or (lieu va)) ((cac tu) or (cac toi)) va dan va cua tre*.