Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang ma » tang ma, sang ma, nang cao
van cau » van dau, van hau, van chat
duc ban » duc tan, duc van, dua ban
hanh va » hang va
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: su sach ty nang ma hoa. hieu van cau ((duc ban) or (duc va)) ((hanh vi) or (hanh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang ma hoa. hieu van cau ((duc ban) OR (duc va)) ((hanh vi) OR (hanh va)) cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ty nang ma hoa. hieu van cau ((duc ban) or (duc va)) ((hanh vi) or (hanh va)) cua tre*.