Perhaps you should try some spelling variations:
kham chua » kham pha
van kham » van tham, va kham, van khai
thu nang » thi nang, thu hang, thu bang
va thanh » gia thanh, ban thanh, va tinh
hieu van » hieu va, thien van, lieu va
sach thu » sach thue, sach thieu, sach tham
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va danh, ban hanh
so sach » so sanh, bo sach, co sach
mai hoi » mai khoi, dai hoi, lai hoi
ma hoi » xa hoi, ma hoa, me hoi
cua te » cua tu

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 thu nang ((ma hoi) OR (mai hoi)). hieu van kham chua ((va hanh) or (va thanh)) vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach thu nang ((ma hoi) OR (mai hoi)). hieu van kham chua ((va hanh) OR (va thanh)) vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach thu nang ((ma hoi) OR (mai hoi)). hieu van kham chua ((va hanh) or (va thanh)) vai cua te".
• Adding a wildcard symbol may retrieve word variants: so sach thu nang ((ma hoi) OR (mai hoi)). hieu van kham chua ((va hanh) or (va thanh)) vai cua te*.