Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
gian cua » gian xu, ban cua
so sach » so sanh, bo sach, co sach
ky sang » ky dang, ky tang, duy sang
hieu va » lieu va, hieu qua
via cua » gia cua, giau cua, rija cua
va bao » va bai
bao bo » bac bo, ban bo, nao bo
bo van » vo van, so van, do van

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 ((ky sang) or (ky nang)) xa hoi. hieu va bao bo van hanh ((via cua) or (gian cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((ky sang) OR (ky nang)) xa hoi. hieu va bao bo van hanh ((via cua) OR (gian cua)) triet.
• Adding a wildcard symbol may retrieve word variants: so sach ((ky sang) or (ky nang)) xa hoi. hieu va bao bo van hanh ((via cua) or (gian cua)) triet*.