Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
tay dang » tay dong, tay dung, tay lang
manh hai » lanh hai, minh hai, thanh hai
tac dung » sach dung, xay dung, tin dung
hai cua » thai cua, dai cua, hoi cua
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
xay hoi » xa hoi, tay hoi, cay phoi
va cam » va cham, va cac, va cao
xuc va » duc va, luc va, xac va
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ((tay dang) or (tac dung)) xay hoi. hieu va cam ((xuc va) OR (tuc va)) manh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((tay dang) OR (tac dung)) xay hoi. hieu va cam ((xuc va) OR (tuc va)) manh hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((tay dang) or (tac dung)) xay hoi. hieu va cam ((xuc va) OR (tuc va)) manh hai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ((tay dang) or (tac dung)) xay hoi. hieu va cam ((xuc va) OR (tuc va)) manh hai cua tre*.