Perhaps you should try some spelling variations:
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
van hanh » van thanh, ban hanh, van anh
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
va hanh » va thanh, va danh, ban hanh
doi cua » dai cua, hoi cua
sai ky » sac ky
cua tu » cua tuc, cua su, cua cu
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: thuoc ((sai ky) or (sach ty)) nang x hoi. hieu va cac nuoc ((va hanh) OR (van hanh)) doi cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc ((sai ky) OR (sach ty)) nang x hoi. hieu va cac nuoc ((va hanh) OR (van hanh)) doi cua tu*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc ((sai ky) or (sach ty)) nang x hoi. hieu va cac nuoc ((va hanh) OR (van hanh)) doi cua tu*".