Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh tai » thanh tai, hang tai, han tai
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet

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 xa hoi. ((((hieu ve) OR (hieu van))) or (hieu qua)) cau truc va hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang xa hoi. ((((hieu ve) OR (hieu van))) OR (hieu qua)) cau truc va hanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang xa hoi. ((((hieu ve) OR (hieu van))) or (hieu qua)) cau truc va hanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang xa hoi. ((((hieu ve) OR (hieu van))) or (hieu qua)) cau truc va hanh tai cua tre*.