Perhaps you should try some spelling variations:
thu dang » thu bang, thu dong, thu sang
thu hang » thi hang, thuc hanh, thu huong
te sach » toc sach
hanh di » hanh de, hang di, danh di
luc van » luoc van, luu van, duc van
hieu va » lieu va, hieu qua
cac luc » cau luc, coc luc, cac nuoc
xay hoi » xa hoi, tay hoi, cay phoi
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: te sach ((thu dang) OR (thu hang)) xay hoi. hieu va cac luc van ((hanh di) or (hanh vi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((thu dang) OR (thu hang)) xay hoi. hieu va cac luc van ((hanh di) OR (hanh vi)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((thu dang) OR (thu hang)) xay hoi. hieu va cac luc van ((hanh di) or (hanh vi)) cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ((thu dang) OR (thu hang)) xay hoi. hieu va cac luc van ((hanh di) or (hanh vi)) cua tre*.