Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
van hanh » ban hanh, van anh, van ban
cac thoi » cac toi, cac hop, cac tro
hieu va » lieu va, hieu qua
sach tu » sach thu, cach tu, sach uu
may hoi » may thoi, tay hoi, mai hoi
sach ty » sach y, sach thu, xach tay
vi cua » vai cua, di cua
cua te » cua tu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sach tu) OR (sach ty)) mang may hoi. hieu va cac thoi ((van hanh) OR (van thanh)) vi cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((sach tu) OR (sach ty)) mang may hoi. hieu va cac thoi ((van hanh) or (van thanh)) vi cua te~".
• Adding a wildcard symbol may retrieve word variants: toc ((sach tu) OR (sach ty)) mang may hoi. hieu va cac thoi ((van hanh) or (van thanh)) vi cua te*.