Perhaps you should try some spelling variations:
thuoc cach » thuoc sach, thuc cach, truoc cach
ban thanh » ban hanh, ban hang
thanh van » thanh san, thanh toan, thanh phan
cach hoc » cach thuc, cach thoi, dich hoc
khoa hoc » hoa hoc
so toan » so tan, so than, bao toan
hoc xua » hoc cua, hoc xa, hoc lua
xua hai » qua hai, cua hai, xa hai
hai ban » hai bang, hai ba, tai ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc cach hoc tap, nghien ((cac cong) or (cua cong)) so toan khoa hoc xua hai ban thanh van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc cach hoc tap, nghien ((cac cong) OR (cua cong)) so toan khoa hoc xua hai ban thanh van.
• Adding a wildcard symbol may retrieve word variants: thuoc cach hoc tap, nghien ((cac cong) or (cua cong)) so toan khoa hoc xua hai ban thanh van*.