Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
dan hanh » dang hanh, dan khanh, dan thanh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
ve cham » va cham, ve chat, vu cham
cua tre » cua te, cuu tre, cua triet
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: tu sach ky ((nang xa) or (nang x)) hoi. hieu ((ve cham) or (vien cac)) hoc dan hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (nang x)) hoi. hieu ((ve cham) OR (vien cac)) hoc dan hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (nang x)) hoi. hieu ((ve cham) or (vien cac)) hoc dan hanh vi cua tre*.