Perhaps you should try some spelling variations:
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
vai cuu » vai cua
cuu tre » cua tre, cau tren, cau treo
hieu ve » hieu va
nang ma » tang ma, sang ma, nang cao
cam tu » cam thu, nam tu, dam tu
tu van » tu 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 ty ((nang ma) or (nang x)) hoi. ((hieu ve) OR (hieu van)) cam tu van hanh vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((nang ma) OR (nang x)) hoi. ((hieu ve) OR (hieu van)) cam tu van hanh vai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((nang ma) or (nang x)) hoi. ((hieu ve) OR (hieu van)) cam tu van hanh vai cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((nang ma) or (nang x)) hoi. ((hieu ve) OR (hieu van)) cam tu van hanh vai cuu tre*.