Perhaps you should try some spelling variations:
nganh khong » nganh cong, nhanh chong, nganh nong
nganh khoa » nganh hoa, doanh khoa, anh khoa
sach hoc » cach hoc, sach hoi, mach hoc
cuu dong » cuu cong, cuu tong, cuu long
dong luc » nang luc
tu sach » thu sach, su sach, te sach
va pham » van pham, va phat, va phap
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 hoc tap, nghien cuu dong luc ((nganh khoa) OR (nganh khong)) hoc ma hoi va pham van~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach hoc tap, nghien cuu dong luc ((nganh khoa) OR (nganh khong)) hoc ma hoi va pham van".
• Adding a wildcard symbol may retrieve word variants: tu sach hoc tap, nghien cuu dong luc ((nganh khoa) OR (nganh khong)) hoc ma hoi va pham van*.