Perhaps you should try some spelling variations:
cay thuoc » cua thuoc, nam thuoc, va thuoc
van thanh » ban thanh, van tuan
thanh di » thanh doi, thanh de, thanh do
thu sach » thuat sach, thuoc sach, thu hoach
van pham » san pham, van phan, van phat
hieu van » hieu va, thien van, lieu va
duc van » duc va, duc tan, duc manh
tu sach » su sach, te sach, tu cach
dai hoi » dai hoc, dai hai, dai moi
mai hoi » mai khoi, lai hoi, mai doi
v nang » va nang, vu nang, van nang
di cay » doi cay, di cau, si cay

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) or (thu sach)) v nang ((mai hoi) or (dai hoi)). hieu van pham duc van thanh di cay thuoc~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) v nang ((mai hoi) OR (dai hoi)). hieu van pham duc van thanh di cay thuoc.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) v nang ((mai hoi) or (dai hoi)). hieu van pham duc van thanh di cay thuoc*.