Perhaps you should try some spelling variations:
thanh vi » hanh vi, thanh va, thanh ve
va thanh » gia thanh, ban thanh, va tinh
hieu van » hieu va, thien van, lieu va
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
cac toc » cac toi, cac nuoc, cac thoi
cac tac » cac bac, cac dac, cac tai
cua tre » cua te, cuu tre, cua triet
cac tuc » cac tu, cac nuoc, cac cuoc
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ky tang xa hoi. hieu van ((((cac tuc) OR (cac tac))) or (cac toc)) va thanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky tang xa hoi. hieu van ((((cac tuc) OR (cac tac))) OR (cac toc)) va thanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky tang xa hoi. hieu van ((((cac tuc) OR (cac tac))) or (cac toc)) va thanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: vu sach ky tang xa hoi. hieu van ((((cac tuc) OR (cac tac))) or (cac toc)) va thanh vi cua tre*.