Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang som » nang song, nang soan, nang doc
cac ban » cac dan, cac van, can ban
cuc ban » cua ban, cuu ban, duc ban
cuu tre » cua tre, cau tren, cau treo
hieu ve » hieu va, hieu van
som hoc » so hoc
su sach » so sach, vu sach
vi cuu » vi luu, vinh cuu
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) or (su sach)) ky nang som hoc. hieu ve cac ((cuc ban) or (cac ban)) hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (su sach)) ky nang som hoc. hieu ve cac ((cuc ban) OR (cac ban)) hanh vi cuu tre.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (su sach)) ky nang som hoc. hieu ve cac ((cuc ban) or (cac ban)) hanh vi cuu tre*.