Perhaps you should try some spelling variations:
cach thoi » cac thoi, cach thuc, cach noi
phan phoi » phan thi
thoi tap » toi tap, hoc tap, thoi dai
hoc phan » hoc dan, hoc pho
phoi hoc » hoi hoc, phoi thuoc, hoa hoc
tap toan » tap doan, tap quan, bai toan
su cach » su sach, tu cach, su cac
va toan » van toan, bai toan, va thanh
mo hoc » mon hoc, co hoc
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 thoi tap, nghien cuu mo hoc phan phoi hoc xa hoi ((va toan) or (tap toan)) tai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su cach thoi tap, nghien cuu mo hoc phan phoi hoc xa hoi ((va toan) OR (tap toan)) tai.
• Adding a wildcard symbol may retrieve word variants: su cach thoi tap, nghien cuu mo hoc phan phoi hoc xa hoi ((va toan) or (tap toan)) tai*.