Perhaps you should try some spelling variations:
nganh khoa » nganh hoa, nganh khong, doanh khoa
hoc nganh » hoc nhanh
nhan dann » nhan dang, phan dang, nhac dan
sach hoc » cach hoc, sach hoi, mach hoc
cuu dong » cuu cong, cuu tong, cuu long
dong hoc » dong co, dong luc
khoa hoc » hoa hoc
nhan dan » phan dau, gian dan, nhan tai
tu sach » thu sach, su sach, te sach
hoc mai » hoc ma, hoc dai, hoc bai
mai hoi » mai khoi, dai hoi, lai hoi

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