Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh van » thanh san, thanh toan, thanh phan
sach hoc » cach hoc, mach hoc, sach duoc
sach hoi » sach doi, sach moi, cach thoi
cuu cong » cua cong, thu cong, cac cong
khoa hoc » hoa hoc
cong so » cong san, cong hoa
so toan » so tan, so than, bao toan
hai ban » hai bang, hai ba, tai ban
hoc xa » hoc ma
xa hai » xa thai, xua hai, xa hoi

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 hoc) OR (sach hoi)) tap, nghien cuu cong so toan khoa hoc xa hai ban thanh van~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc ((sach hoc) OR (sach hoi)) tap, nghien cuu cong so toan khoa hoc xa hai ban thanh van".
• Adding a wildcard symbol may retrieve word variants: thuoc ((sach hoc) OR (sach hoi)) tap, nghien cuu cong so toan khoa hoc xa hai ban thanh van*.