Perhaps you should try some spelling variations:
hoc khanh » hoc nhanh, hoc thanh, hoc hanh
khanh hoa » thanh hoa, hang hoa
sach hoc » cach hoc, sach hoi, mach hoc
nhan van » nhan dan, nhan va, phan van
gian dan » gian lang
tu sach » thu sach, su sach, te sach
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 hoc tap, nghien cuu mo hoc khanh hoa hoc xa hoi va ((nhan van) or (gian dan))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach hoc tap, nghien cuu mo hoc khanh hoa hoc xa hoi va ((nhan van) OR (gian dan)).
• Adding a wildcard symbol may retrieve word variants: tu sach hoc tap, nghien cuu mo hoc khanh hoa hoc xa hoi va ((nhan van) or (gian dan))*.