Perhaps you should try some spelling variations:
nghien huu » nghien cuu, nguyen huu, nhiem huu
tran khoa » toan khoa, san khoa, nhan khoa
sach hoc » cach hoc, mach hoc, sach duoc
sach hoi » sach doi, sach moi, cach thoi
hoc tran » hoc tan, hoc tren, boc tran
khoa hoc » hoa hoc
nhan dan » phan dau, gian dan, nhan tai
huu mot » cuu mot, huy mot, hieu mot
mot hoc » mon hoc, mo hoc, mot goc
va nhan » van nhan, ca nhan, va phan
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: hoc ((sach hoc) OR (sach hoi)) tap, nghien huu mot hoc tran khoa hoc xa hoi va nhan dan~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((sach hoc) OR (sach hoi)) tap, nghien huu mot hoc tran khoa hoc xa hoi va nhan dan".
• Adding a wildcard symbol may retrieve word variants: hoc ((sach hoc) OR (sach hoi)) tap, nghien huu mot hoc tran khoa hoc xa hoi va nhan dan*.