Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nam thuc, nham thu
cua viet » ca viet, hoa viet, cua vat
hanh vai » hanh va, hanh tai, hanh van
dang xay » dang van, van xay
thuc ban » thuoc ban, thuc dan, thu ban
hieu va » hieu qua
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
sac ky » cac ky, sai ky
tu sac » tu sach, tu cac, tu san

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky dang xay hoi. ((hieu va) or (lieu va)) nham thuc ban ((hanh vai) OR (hanh vi)) cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky dang xay hoi. ((hieu va) OR (lieu va)) nham thuc ban ((hanh vai) OR (hanh vi)) cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky dang xay hoi. ((hieu va) or (lieu va)) nham thuc ban ((hanh vai) OR (hanh vi)) cua viet".
• Adding a wildcard symbol may retrieve word variants: tu sac ky dang xay hoi. ((hieu va) or (lieu va)) nham thuc ban ((hanh vai) OR (hanh vi)) cua viet*.