Perhaps you should try some spelling variations:
thien van » thi van
hieu van » hieu va, lieu va, hieu ve
ban hanh » ban hang
toc sach » hoc sach, doc sach, thuoc sach
dang xay » dang van, van xay
cham cuu » cap cuu, chat cua
cuu ban » cuu van, cua ban, cuu san
xay hoi » xa hoi, tay hoi, cay phoi
cua tre » cua te, cuu tre, cua triet
y dang » ky dang, 2 dang, _ dang
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: ((te sach) OR (toc sach)) y dang xay hoi. ((hieu van) or (thien van)) cham cuu ban hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) y dang xay hoi. ((hieu van) OR (thien van)) cham cuu ban hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) y dang xay hoi. ((hieu van) or (thien van)) cham cuu ban hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) y dang xay hoi. ((hieu van) or (thien van)) cham cuu ban hanh vi cua tre*.