Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
hanh tai » thanh tai, hang tai, han tai
tu cach » tu cac
su sach » so sach, vu sach
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
xe hanh » ve hanh, de thanh, den hanh
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu cach) or (su sach)) ky nang ma hoi. ((hieu van) OR (hieu va)) nam thu xe hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (su sach)) ky nang ma hoi. ((hieu van) OR (hieu va)) nam thu xe hanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu cach) or (su sach)) ky nang ma hoi. ((hieu van) OR (hieu va)) nam thu xe hanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (su sach)) ky nang ma hoi. ((hieu van) OR (hieu va)) nam thu xe hanh tai cua tre*.