Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, te sach, tu cach
tuc van » thuc van, truc van, tuc va
cac tuc » cac toc, cac tu, cac tac
van cac » van hac, van cau, van bac
ky tang » ky nang, ky dang, kho tang
ky sang » ky nang, ky dang, duy sang
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
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: ((tu sach) or (su sach)) ((ky sang) or (ky tang)) ma hoa. hieu van cac tuc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ((ky sang) OR (ky tang)) ma hoa. hieu van cac tuc van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ((ky sang) or (ky tang)) ma hoa. hieu van cac tuc van hanh vi cua tre*.