Perhaps you should try some spelling variations:
hanh thai » nhanh thai, hinh thai, hanh tai
thai cua » than cua, tai cuc, tri cua
nhan luc » nang luc
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
sach ty » sach y, sach tu, sach thu
va hanh » van hanh, va thanh, va danh
hac luc » than luc
mang xa » lang xa, mang may, dang xay
xang xa » lang xa, ang xa, dang xay
cua tre » cua te, cuu tre, cua triet

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 ty ((xang xa) or (mang xa)) hoi. hieu van ((hac luc) OR (nhan luc)) va hanh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty ((xang xa) OR (mang xa)) hoi. hieu van ((hac luc) OR (nhan luc)) va hanh thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty ((xang xa) or (mang xa)) hoi. hieu van ((hac luc) OR (nhan luc)) va hanh thai cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ty ((xang xa) or (mang xa)) hoi. hieu van ((hac luc) OR (nhan luc)) va hanh thai cua tre*.