Perhaps you should try some spelling variations:
hoc sach » hoc cac, hoc anh
hieu van » hieu va, thien van, lieu va
thanh ve » hanh ve, thanh va, thanh vien
thanh vi » hanh vi, thanh va, nhanh vi
cau luc » cau truc, cau phuc
van cau » van dau, van hau, van chat
nang ma » tang ma, sang ma, nang cao
cuu tre » cua tre, cau tren, cau treo
luc va » duc va, tuc va, loc va
ma hoi » mai hoi, xa hoi, ma hoa

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) or (hoc sinh)) ky nang ma hoi. hieu van cau luc va ((thanh vi) OR (thanh ve)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (hoc sinh)) ky nang ma hoi. hieu van cau luc va ((thanh vi) OR (thanh ve)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc sach) or (hoc sinh)) ky nang ma hoi. hieu van cau luc va ((thanh vi) OR (thanh ve)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) or (hoc sinh)) ky nang ma hoi. hieu van cau luc va ((thanh vi) OR (thanh ve)) cuu tre*.