Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cuu tre, cua triet
tuc va » truc va, tuc xa, duc va
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu bach) or (toc sach)) ky nang xa hoi. hieu ve cham ((tuc va) OR (thuc va)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu bach) OR (toc sach)) ky nang xa hoi. hieu ve cham ((tuc va) OR (thuc va)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu bach) or (toc sach)) ky nang xa hoi. hieu ve cham ((tuc va) OR (thuc va)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((vu bach) or (toc sach)) ky nang xa hoi. hieu ve cham ((tuc va) OR (thuc va)) hanh vi cua tre*.