Perhaps you should try some spelling variations:
nganh khong » nganh cong, nhanh chong, nganh nong
nganh khoa » nganh hoa, doanh khoa, anh khoa
sach doi » sach hoi, sach moi, sach dao
nhan dan » phan dau, gian dan, nhan tai
tu sach » thu sach, su sach, te sach
doi tap » doi tac, doi dap, doi tai
cuu mot » cua mot, cuu mo, huu mot
mot hoc » mon hoc, mo hoc, mot goc
va nhan » van nhan, ca nhan, va phan
ma hoi » mai hoi, xa hoi, ma hoa

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 doi tap, nghien cuu mot hoc ((nganh khoa) or (nganh khong)) hoc ma hoi va nhan dan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach doi tap, nghien cuu mot hoc ((nganh khoa) OR (nganh khong)) hoc ma hoi va nhan dan.
• Adding a wildcard symbol may retrieve word variants: tu sach doi tap, nghien cuu mot hoc ((nganh khoa) or (nganh khong)) hoc ma hoi va nhan dan*.