Perhaps you should try some spelling variations:
cach thoi » cac thoi, cach thuc, cach noi
cach hoi » cach noi, cach hoc, sach hoi
hoc toan » hoc tan, hop toan, hoa toan
khoa hoc » hoa hoc
van nhan » van phan, van thanh, danh nhan
nhan dan » phan dau, gian dan, nhan tai
cuu mot » cua mot, cuu mo, huu mot
mot hoc » mon hoc, mo hoc, mot goc
hoi van » hoi va, hoi dan, hai van
hoc xa » hoc ma

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((cach hoi) OR (cach thoi)) dap, nghien cuu mot hoc toan khoa hoc xa hoi van nhan dan~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((cach hoi) OR (cach thoi)) dap, nghien cuu mot hoc toan khoa hoc xa hoi van nhan dan".
• Adding a wildcard symbol may retrieve word variants: su ((cach hoi) OR (cach thoi)) dap, nghien cuu mot hoc toan khoa hoc xa hoi van nhan dan*.