Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
cham hoc » cham soc, chat hoc, cham hoi
nang tai » tang tai, sang tai, nang cao
hang tai » hang va, dung tai
su sach » so sach, vu sach
bai cua » ban cua, bai ca, hai cua
hoc ban » hoc bang, hoc dan, hoc bai
hieu va » lieu va, hieu qua
va cham » va chat, va tham
sach ky » sac ky, sach y, sach ty

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 tai) or (hang tai)) roi. hieu va cham hoc ban thanh ((bai cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang tai) OR (hang tai)) roi. hieu va cham hoc ban thanh ((bai cua) OR (dai cua)) tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang tai) or (hang tai)) roi. hieu va cham hoc ban thanh ((bai cua) or (dai cua)) tre*.