Perhaps you should try some spelling variations:
dang xay » dang van, van xay
va thanh » gia thanh, ban thanh, va tinh
thanh de » hanh de, thanh ve, thanh do
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cac dac » cac dan, cac dai, cac bac
cua tre » cua te, cuu tre, cua triet
dac va » duc va, day va, dat va
de cua » le cua, te cua, dieu cua

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 xa) or (dang xay)) hoi. hieu va cac dac va thanh de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang xa) OR (dang xay)) hoi. hieu va cac dac va thanh de cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) or (dang xay)) hoi. hieu va cac dac va thanh de cua tre*.