Perhaps you should try some spelling variations:
dan khoa » dang khoa, da khoa, san khoa
khoa hoc » hoa hoc
tu sach » thu sach, su sach, te sach
tu hanh » du hanh, lu hanh, thuc hanh
va nhan » van nhan, ca nhan, va phan
nhan va » nhan tai, nhan dan, nhan tao
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: ((tu sach) or (tu hanh)) hoc tap, nghien cuu mo hoc dan khoa hoc xa hoi va nhan va~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (tu hanh)) hoc tap, nghien cuu mo hoc dan khoa hoc xa hoi va nhan va.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (tu hanh)) hoc tap, nghien cuu mo hoc dan khoa hoc xa hoi va nhan va*.