Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
hieu van » thien van, lieu va, hieu ve
hanh va » hang va, hanh vi
va hanh » van hanh, va thanh, va danh
cam luc » cam xuc, cau luc
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
sach v » sach va, sach y, sach 2
luc va » duc va, tuc va, loc va
va cua » va chua, via cua, ca cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach v ((nang xa) OR (nang ma)) hoi. ((hieu va) or (hieu van)) cam luc va hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach v ((nang xa) OR (nang ma)) hoi. ((hieu va) OR (hieu van)) cam luc va hanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach v ((nang xa) OR (nang ma)) hoi. ((hieu va) or (hieu van)) cam luc va hanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: hoc sach v ((nang xa) OR (nang ma)) hoi. ((hieu va) or (hieu van)) cam luc va hanh va cua tre*.