Perhaps you should try some spelling variations:
nam thuoc » nam thu, nha thuoc, cay thuoc
cua viet » ca viet, hoa viet, cua vat
nam thuc » am thuc, nam thu, nam tu
thi nang » thi cong, ki nang
vat hanh » vat thanh, van hanh, va hanh
thi hanh » thi thanh
hanh ve » hanh vi, hanh va, hanh kem
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
ve cua » le cua, de cua, te cua
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((thi nang) OR (thi hanh)) x hoi. hieu va ((nam thuc) or (nam thuoc)) vat hanh ve cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((thi nang) OR (thi hanh)) x hoi. hieu va ((nam thuc) OR (nam thuoc)) vat hanh ve cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((thi nang) OR (thi hanh)) x hoi. hieu va ((nam thuc) or (nam thuoc)) vat hanh ve cua viet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((thi nang) OR (thi hanh)) x hoi. hieu va ((nam thuc) or (nam thuoc)) vat hanh ve cua viet*.