Perhaps you should try some spelling variations:
sach tranh » canh tranh
sach tren » sach tien
cach thuc » anh thuc, cac thu
thuoc ban » thuoc tan, thuoc dang, thu ban
ban khong » ban thong, bay khong, san khong
khi phong » thi phuong, thai phong, hai phong
khi tuong » khai thuong, khoi truong, thi truong

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc ((((sach tren) or (sach tranh))) or (cach thuc)) thuoc ban khong ((khi phong) or (khi tuong))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc ((((sach tren) OR (sach tranh))) OR (cach thuc)) thuoc ban khong ((khi phong) OR (khi tuong)).
• Adding a wildcard symbol may retrieve word variants: thuoc ((((sach tren) or (sach tranh))) or (cach thuc)) thuoc ban khong ((khi phong) or (khi tuong))*.