Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, te sach, tu cach
vai cuu » vai cua
tuc van » thuc van, truc van, tuc va
cam tuc » cam xuc, cam tu, nam thuc
cuu tre » cua tre, cau tren, cau treo
hieu ve » hieu va
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
su sach » so sach, vu sach

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) or (su sach)) ty nang xa hoi. ((hieu ve) or (hieu van)) cam tuc van hanh vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ty nang xa hoi. ((hieu ve) OR (hieu van)) cam tuc van hanh vai cuu tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ty nang xa hoi. ((hieu ve) or (hieu van)) cam tuc van hanh vai cuu tre*.