Perhaps you should try some spelling variations:
cac thoi » cac toi, cac hop, cac tro
thoi tap » toi tap, hoc tap, thoi dai
dan khoa » dang khoa, da khoa, san khoa
khoa hoc » hoa hoc
cac nhan » ca nhan, cac nha, cam nhan
nhan dan » phan dau, gian dan, nhan tai
hoc cac » hoc cao
su cac » tu cac, su cao, su can
hoc xa » hoc ma
xa hoc » xa hoi, va hoc, xa hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: su cac thoi tap, nghien ((huu tung) or (cuu mo)) hoc dan khoa hoc xa hoc cac nhan dan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su cac thoi tap, nghien ((huu tung) OR (cuu mo)) hoc dan khoa hoc xa hoc cac nhan dan.
• Adding a wildcard symbol may retrieve word variants: su cac thoi tap, nghien ((huu tung) or (cuu mo)) hoc dan khoa hoc xa hoc cac nhan dan*.