Perhaps you should try some spelling variations:
phan trac » phan tap, phan cac, phan tan
phan truc » phan thuc, phan tu, phan duc
ban hanh » ban hang
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
van anh » van thanh, tuan anh, van minh
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa
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: su sach ky nang ma hoi. hieu van ((phan truc) or (phan trac)) ((ban hanh) or (van anh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ma hoi. hieu van ((phan truc) OR (phan trac)) ((ban hanh) OR (van anh)) vi cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ma hoi. hieu van ((phan truc) or (phan trac)) ((ban hanh) or (van anh)) vi cua tre*.