Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
hieu van » hieu va, thien van, lieu va
nam duoc » nam thuoc, da duoc, dat duoc
duoc may » duoc ma, duoc ly, hoc may
tinh via » tinh gia, tinh va, tinh vi
so sach » so sanh, bo sach, co sach
via cua » gia cua, gian cua, giau cua
cua tre » cua te, cuu tre, cua triet
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) or (hoc sach)) ky nang x hoi. hieu van nam duoc may tinh via cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (hoc sach)) ky nang x hoi. hieu van nam duoc may tinh via cua tre.
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (hoc sach)) ky nang x hoi. hieu van nam duoc may tinh via cua tre*.