Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
hieu van » hieu va, thien van, lieu va
dung sai » dung tai, dung va, dung dat
danh sai » danh bat, danh dau, hanh san
cham tuc » nham thuc, pham thuc, tham thuc
van cham » van chat, van tham, va cham
hoc sach » hoc sinh, hoc cac, hoc anh
nang xa » nang x, lang xa, nang ma
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: ((toc sach) or (hoc sach)) ky nang xa hoi. hieu van cham tuc xa ((danh sai) OR (dung sai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) ky nang xa hoi. hieu van cham tuc xa ((danh sai) OR (dung sai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (hoc sach)) ky nang xa hoi. hieu van cham tuc xa ((danh sai) OR (dung sai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sach)) ky nang xa hoi. hieu van cham tuc xa ((danh sai) OR (dung sai)) cua tre*.