Perhaps you should try some spelling variations:
sach doi » sach hoi, sach moi, sach dao
vu sach » vu bach, su sach, vu khach
danh vi » hanh vi, dinh vi, danh di
vu cham » va cham, vu kham, tu cham
hieu vu » hieu va, hieu ve, hieu su
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
soc va » loc va, doc va, goc va
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: vu sach doi ((nang x) or (nang ma)) hoi. hieu vu cham ((soc va) or (hoc va)) danh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach doi ((nang x) OR (nang ma)) hoi. hieu vu cham ((soc va) OR (hoc va)) danh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: vu sach doi ((nang x) or (nang ma)) hoi. hieu vu cham ((soc va) or (hoc va)) danh vi cua tre*.