Perhaps you should try some spelling variations:
manh tang » manh thang, manh tung, anh tang
tang tai » hang tai, dung tai, sang tao
sach hay » sach han, sach ha, sach nay
dung xay » dang xay, dung may, dung tay
duc manh » suc manh, duc anh, duc minh
sach tay » xach tay, sach nay, sach tai
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
xay hoi » xa hoi, tay hoi, cay phoi
cuc te » cua te, cuc tieu
thue » thu, thuc, thuy

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

• Performing a fuzzy search may retrieve terms with similar spellings: so ((sach tay) OR (sach hay)) dung xay hoi. hieu va cac duc manh tang tai ((cuc te) or (cuc thue))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach tay) OR (sach hay)) dung xay hoi. hieu va cac duc manh tang tai ((cuc te) OR (cuc thue)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sach tay) OR (sach hay)) dung xay hoi. hieu va cac duc manh tang tai ((cuc te) or (cuc thue))".
• Adding a wildcard symbol may retrieve word variants: so ((sach tay) OR (sach hay)) dung xay hoi. hieu va cac duc manh tang tai ((cuc te) or (cuc thue))*.